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  • Review
  • Open Access

Coping with drought: stress and adaptive mechanisms, and management through cultural and molecular alternatives in cotton as vital constituents for plant stress resilience and fitness

  • 1, 2,
  • 1,
  • 3, 4,
  • 4,
  • 5, 6, 7,
  • 8 and
  • 1Email author
Contributed equally
Biological Research201851:47

https://doi.org/10.1186/s40659-018-0198-z

  • Received: 17 August 2018
  • Accepted: 7 November 2018
  • Published:

Abstract

Increased levels of greenhouse gases in the atmosphere and associated climatic variability is primarily responsible for inducing heat waves, flooding and drought stress. Among these, water scarcity is a major limitation to crop productivity. Water stress can severely reduce crop yield and both the severity and duration of the stress are critical. Water availability is a key driver for sustainable cotton production and its limitations can adversely affect physiological and biochemical processes of plants, leading towards lint yield reduction. Adaptation of crop husbandry techniques suitable for cotton crop requires a sound understanding of environmental factors, influencing cotton lint yield and fiber quality. Various defense mechanisms e.g. maintenance of membrane stability, carbon fixation rate, hormone regulation, generation of antioxidants and induction of stress proteins have been found play a vital role in plant survival under moisture stress. Plant molecular breeding plays a functional role to ascertain superior genes for important traits and can offer breeder ready markers for developing ideotypes. This review highlights drought-induced damage to cotton plants at structural, physiological and molecular levels. It also discusses the opportunities for increasing drought tolerance in cotton either through modern gene editing technology like clustered regularly interspaced short palindromic repeat (CRISPR/Cas9), zinc finger nuclease, molecular breeding as well as through crop management, such as use of appropriate fertilization, growth regulator application and soil amendments.

Keywords

  • Drought
  • Leaf physiology
  • Antioxidant
  • CRISPR/Cas9
  • miRNAs
  • Climate change
  • Phytohormones
  • Zinc finger nuclease

Introduction

Recent climate change investigation has reported that global escalation of storms, flooding and other severe weather episodes with growing temperatures may ultimately disrupt crop production [1]. Global circulation models projected an increase of 4–5.8 °C in the surface air temperatures over the next few decades. From 1979 to 2003, an increase of 0.35 and 1.13 °C have already documented in the annual mean maximum and minimum temperatures respectively, at the International Rice Research Institute, Manila, Philippines [26]. These temperature increases have likely exposed crops globally to drought induced stress [715]. Tackled with shortage of water reserves, drought is the single most serious risk to world food safety. Drought severity is unpredictable as it depends on several factors, for instance rainfall amount and distribution, evaporative demands and moisture storing ability of soils [1619]. Uncertainties in weather conditions can result in decreased rainfall coupled with increased evapotranspiration. These occurrences can lead to drought and substantial reductions in cotton yield. Over the las 50 years, drought stress alone was responsible for approximately 67% of the cotton lint yield losses in USA, one of the top cotton producing countries in the world [20].

Cotton crop is very sensitive to cold, soil salinity, heat and drought stress [21]. For instance, episodic drought events can cause severe lint yield penalty and may become a significant challenge for sustainable crop production [22]. On the contrary, even a small but adequately timed irrigation can significantly improve water-stressed crop [23, 24]. Drought-induced lint yield penalties in cotton may vary from 50 to 73% [25]. In dry the regions, accounting that 30–60% of total irrigation water supplied to the soil is lost through evaporation which may cause drought [26]. Crops producing areas are already facing a continuous decline of irrigation water [27], and hence, there is a need to establish and design policies to protect crops from extreme weather events [28]. One of the most commonly used strategy, is breeding of stress-tolerant crop for any water-scarce based calamity.

Yield improvement and yield stability under both normal and moisture stress environment is essential for cotton crops. Tolerance to drought stress in cotton is a complex trait that depends on various environmental and physiological factors. Therefore, a sound understanding of the plant morpho-physiological, molecular and biochemical mechanisms, responses to water deficit may provide a means to identify and confer tolerance in terms of agronomic, molecular, and genetic aspects. The adaptive strategies used by drought tolerant plants are of major importance for improving performance of cotton crop under erratic water deficit conditions.

For instance, improvements in production systems and breeding programs have substantially increased cotton lint yield. These published literature will enable the development of crop plants better able to tolerate and thrive under future climatic conditions and so maintain production potential. To our knowledge, no such comprehensive and accumulative data are available to elucidate biochemical, morphological, physiological and molecular adaptive mechanisms of cotton to harsh environment, particularly drought.

Structural and physiological responses to drought

Drought results in a wide range of variations at the developmental and functional level of cotton plants. For example, drought severely impedes various physiological processes, which regulate lint production and fiber quality [29].

Drought resistance mechanisms in plants are composed of four categories: recovery, avoidance, tolerance and drought escape [30]. Water stress avoidance is the sustaining of important physiological processes such as stomatal regulation, when exposed to mild drought. Drought tolerance is the ability of flora to endure severe dehydration via osmotic adjustment and osmo-protectants [31]. Plants are evolved to regulate growth period to avoid moisture stress; termed as drought escape [32]. Drought recovery is the ability of plants to continue growth after drought injury. In cotton, biochemical, physiological and molecular strategies against drought stress are reviewed in the proceeding sections.

Root growth

Plant roots are crucial for sensing and responding to various external environmental stimuli due to direct contact with soil water and nutrients. Due to difficulty in collecting root structural configuration from dry soils, limited data are available on modification in root systems under drought and most of the studies are conducted on cereal crops. Plant roots respond to the variation in surface soil moisture e.g. water deficit in the upper soil profile leads to deeper root penetration, while excess water in the upper layer reduces root penetration [33], i.e. up to 3 m.

Root growth rates are commonly employed for estimating crop yield losses in cotton crop. Insufficient soil moisture restricts root growth and development and consequently impairs functioning of the aerial parts [33]. Water deficit in the upper soil profile leads to deeper root penetration for greater exploration of moisture and nutrients, while excess of water in the upper layer causes reduced root penetration [33]. Drought reduces above-ground biomass accumulation by decreasing root volume density, root mass density and root length density [34]. These root traits are crucial in the process of tolerance to drought; however, traits such as hydraulic conductance and plant allometry are of great interest to scientists. Rooting system with large number of short and slender lateral roots permits a larger root surface sorption zone than the scattered-type root system in acquiring oxygen and nutrients from soil [22]. Fine root system drives soil processes like carbon cycling and sequestration, nutrient fluxes, structural stabilization and the activity of soil microorganisms [35]. In soil, higher root length, and proliferation in the soil are desirable traits for drought adaptation. However, plant root growth and penetration depend on external oxygen partial pressure in the root zone [36]. Mild drought stress during the initial stage may enhance root elongation but root morphological and physiological activities are seriously hampered under long term water stress hampers [37]. In conclusion, deeper root penetration allows the plant to get greater exploration of deeper soil for water and nutrients. Therefore, it is essential to enhance vertical root distribution to enhance crop growth and development under drought stress.

Cotton lint yield

Lint yield in cotton crops is a complex integration of the various physiological processes; most of which are adversely impacted by water stress. Due to indeterminate growth habit, production of new nodes in a cotton plant depends on water availability. The adverse effects of moisture stress on the yield are associated with the duration and severity of the stress and plant growth stage. Terminal drought substantially limits cotton yield production by inhibiting carbon assimilation, and biomass accumulation [38]. Inhibited carbohydrate production coupled with depletion of stored reserves (i.e. starch) due to continuous respiration [39] reduce translocation of assimilates to reproductive organs [40]. This consequently induces abscission of reproductive structures and boll size reduction [41]. Accelerated abscission of fruits and leaves in drought-stressed cotton crop could be associated with final yield reduction [42]. In brief, cotton yield reduction is directly associated with plant morphological and physiological processes under drought stress.

Fiber quality

Fiber quality is a main aim of cotton breeders both because fiber traits directly affect lint yield and improvement in spinning technology has an increased demand for high-grade fiber [43]. Fiber quality is the combination of fiber length, fiber fineness (cell wall thickness), fiber strength, fiber elasticity, neps (small nodules on the fiber), short fiber index, uniformity index, spinning consistency (suitability of fibers for yarn-spinning), color grade, and reflectance (brightness of fibers) [44]. Fiber quality traits are quantitative and controlled by multiple genes with major and minor phenotypic effects [45]. Water supply during fiber cell development has a direct impact on lint quality [46]. As drought tolerance in plants is a complex phenomenon, associated with a variety of morphological and physiological traits [47], breeding for improved fiber quality traits under moisture stress is cumbersome [48]. Hence, the identification of stable quantitative trait loci (QTL) for irrigated and water deficit environment could facilitate molecular breeding of cotton genotypes with both improved fiber quality and yield attributes. QTL, genetic diversity and structure analysis, require the availability of abundant DNA markers which are continually being developed for the cotton genome [49]. In upland cotton, several QTL analyses have focused on lint yield traits [50, 51], but less attention have been paid to identify QTLs for fiber quality under drought [52]. Saranga et al. [53], used inter-specific F2 and F3 cotton plants derived from a cross between inbred lines of G. hirsutum cv Siv’on and G. barbadense cv F-177. QTLs (13 and 33) under well-watered and water deficit conditions and reported for 16 QTL trait including plant productivity, physiology and fiber quality. Paterson et al. [54] identified 79 QTLs allied with fiber quality traits in F2 and F3 generations derived from G. hirsutum cv Siv’on and G. barbadense cv F-177 under irrigated and deficit water conditions. Seventeen of the identified 79 QTLs were specific to moisture stress conditions, whereas only two were specific to well-watered conditions. Saeed et al. [52] mapped physiological, yield and plant structure traits in an F2 population generated from a cross between G. hirsutum cv. FH-901 (drought sensitive) and G. hirsutum cv. RH-510 (drought tolerant). A total of seven QTLs were detected of which three and two QTLs were specific to water-limited and well-watered conditions, respectively. Such QTL analysis of germplasm panels, which contain G. hirsutum lines with diverse genetic information have the capacity to detect a broader array of useful alleles. In the present study, 177 simple sequence repeat (SSR) markers were used to detect significant quantitative trait loci (QTLs) linked to 11 fiber quality and plant structural traits in a panel of 99 upland cotton genotypes. In another study, fiber quality and plant structural traits were tested under well-watered and water deficit conditions. Analysis of GLM showed that a total of 74 and 70 QTLs under well-watered and limited water conditions were identified, respectively. MLM identified 7 and 23 QTLs under well-water and water deficit, respectively [44].

For instance, for traits of important interest in cotton fibre, efforts have been made to detect the specific fiber associated gene and their functions for improved fiber quality i.e. E6 [55], GhExp1 [56], GhSusA1 [57], PIP2s [58] and GA20ox [59]. Cotton functional genomics promise to enhance the understanding of fundamental plant biology to systematically exploit genetic resources for improvement of cotton fiber quality. However, determining the functions of cotton genes is cumbersome, which has not been fully assessed a rapid pace [60]. Actin cytoskeleton [61], polysaccharide biosynthesis, signal transduction and protein translocation [62] associated genes are expressed in different fiber developmental pathways. Among these genes, few are predominantly expressed during fiber formation [63], secondary cell wall biosynthesis [64], and fiber elongation [65]. Currently, a cotton protodermal factor 1 gene (GbPDF1) was expressed at fiber initiation stage through HDZIP2ATATHB2 core cis-element [66]. While, alpha-expansins (GhExp1) gene had been expressed in developing fibers and encodes a cell wall protein and controls cell wall loosening [56]. Ruan et al. [67] showed that antisense suppression of a sucrose synthase (SuSy) gene interrupted the fiber elongation and signified the contribution of SuSy in osmosis regulation. Conversely, proline-rich proteins coding gene (GhPRP5) performed as a negative regulator during fiber development [68]. Cellulose synthesis is a central event in fiber cells development during the secondary cell wall biosynthesis. Many studies have been done to investigate that how cotton fiber regulates and supports the strong irreversible carbon sink characterized by secondary wall cellulose synthesis [64]. Subsequently, a new Sus isoform (SusC) was discovered, which was up-regulated during secondary wall cellulose formation in the fiber [64]. At fiber maturity, most of the expressed genes were linked to cellular respiration [69]. Many genes encoding transcription factors i.e. MYB, C2H2, bHLH, WRKY and HD-ZIP families have also been expressed during the fiber developmental stage. Past studies indicated that MYB-related genes showed high expression during fiber development in upland cotton [70]. Expression studies of six MYB-associated genes revealed that GhMYB6 has high expression in fiber [71], while R2R3 MYB-like transcription factor encoding gene “GhMYB109” was expressed during fiber elongation and initiation [72]. In the cotton ovule, at fiber initiation the RAD-like GbRL1 is highly expressed [73].

Identification of markers connected to loci for fiber quality under moisture stress can have useful effects in genetic adaptability required to generate necessary fiber under limited water conditions. Numerous gene expression investigations had been performed to understand on cotton fiber development which present some issues. Firstly, majority of differentially expressed genes known by the comparative analysis are linked to difference between species instead of allied with fiber characteristics. Secondly, the application of the protein coding gene sequences from G. raimondii and G. arboreum may not be accurate enough for gene annotation in tetraploid cotton. Thirdly, it is unfamiliar if any of the expressed genes identified from earlier studies had sequence changes between a cotton fiber mutant and its wild-type. Herein, only the differentially expressed genes having sequence variations and co-localization with target fiber characteristics are potential candidates for innovative cotton research.

Photosynthesis

Photosynthesis is the main driver for crop productivity, which is negatively influenced by water deficit conditions. Stomata closing in response to moisture stress results in a reduction in leaf photosynthetic capacity resulting in chloroplast dehydration and decreased CO2 diffusion into the leaf (Fig. 1). For instance, mild moisture stress stimulates stomata closure to reduce water loss by regulating transpiration. This reduces stomatal conductance and limits intercellular CO2 concentration [74]. Under severe drought, reduced stomatal conductance and metabolic (non-stomatal) damage like limited carboxylation becomes major limitations to photosynthesis [75]. Similarly, stomatal conductance is not constantly allied with photosynthesis, although it needs to be investigated [76, 77]. Drought can reduce photosynthesis as well as severely affect transpiration rate and the process depends on the intensity of drought and plant developmental stage [78]. Up to 66% reduction in photosynthesis was noted in mature cotton leaves compared with younger leaves under water deficit conditions [79].
Fig. 1
Fig. 1

Changes in stomatal conductance (gs) and net photosynthetic rate (Pn) of cotton leaves in response to drought stress and recovery. The periods are full squaring to flowering (S1), first flowering to full flowering (S2), full flowering to full boll setting (S3) and full boll setting to boll opening stage (S4), respectively. The water treatments were mild stress or 50–55% of maximum soil water (V1), moderate stressor 40–45% of maximum soil water (V2), and a well-watered check

Stomata regulation

In plants, the main role of stomata is to regulate water loss through transpiration. Under moisture stress, internal moisture preservation and quick stomatal closure are vital for plant withstand to water deficit conditions. Water loss from cotton leaves is a key phenomenon under water deficit conditions but plants use morphological adaptation to survive under drought stress i.e. leaves wilting and rolling leading to less radiation interception, and ultimately decreased water loss [30]. Plants usually show numerous xeromorphic traits and structures that induce drought resistance, i.e. a thick cuticle epidermis, thicker and tiny leaves, smaller and denser stomata, palisade tissues more epidermal trichomes, and a well-structured vascular bundle sheath [80]. Stomatal regulation plays an imperative role in leaf gas exchange between the intracellular cavity of the leaf and external environment. Plant leaves dissipate heat energy through three means. These mechanisms are re-radiation, sensible heat loss (conduction and convection) and transpiration. Of these, transpiration is the most important mechanism that sanctions plants to harvest energy and sustain cellular functions. As 90% of water loss from plants occurs though stomata openings via transpiration [81], stomatal regulation plays a key role in maintaining water and nutrient supplies for essential physiological process. Under high transpiration, stomata closure is the initial step to decrease water loss under drought conditions in cotton crop. Ray and Sinclair [82] reported that among the eight corn (Zea mays L.) hybrids there were statistical differences in the fraction of transpirable soil water at which the stomata began to close during a drying cycle. Hence, stomatal conductance would be a possible indicator for inducing drought tolerance, although a negative correlation is associated between drought resistance and stomata conductance in cotton.

Osmotic adjustment

Osmotic adjustment is an acclimation strategy to sustain higher cellular turgor potential and water retention against moisture stress. In other crop species, osmotic adjustment of leaf is strongly correlated with drought resistance. In response to water stress, osmotic adjustment take place in plant cells via increased of compatible solutes in the cytosol. This reduces the osmotic potential of the cell to sustain cell turgor and development. Compatible solutes like proline, sorbitol, and glycinebetaine, and are more soluble and do not interfere with cell metabolism even at higher concentration [83]. In plants, proline is a common compatible solute under drought stress [83]. However, proline accumulation in droughted plants vary and depends on cultivar and growth stage, (e.g., in cotton ovaries proline accumulation was higher than in the leaf) (Fig. 2). Pilon et al. [84] indicated that osmotic adjustment in cotton during reproductive stages may be higher than during vegetative stages and possibly tissue dependent.
Fig. 2
Fig. 2

Proline concentration (μmol g−1 DM) in the leaves and ovaries of two cotton cultivars. The water treatments were water stress (black bars) and well–watered (gray bars). Different letters indicate significant differences (P ≤ 0.05) [84]

Compatible solutes protect proteins and membranes from the injury occasioned by elevated concentrations of inorganic ions and oxidative damage under water deficit [85] and salinity [86]. Foliar applied proline and glycinebetaine could be an effective strategy for inducing drought tolerance in cotton crops [87]. In cotton plants more glycinebetaine accumulation exhibited more drought tolerance. Thus, promoting physiological process e.g. leaf photosynthetic capacity, relative water content, enhanced osmotic adjustment and low lipid stability through transgenic or non-transgenic techniques may improve crop performance under drought [88]. For example, constitutive expression of a mustard annexin gene, AnnBj, increased proline and sucrose content in cotton resulted in greater drought tolerance [89]. Furthermore, overexpression of GhAnn1, annexin genein cotton, induced drought and salt tolerance by improving superoxide dismutase, activity raised proline concentration and increased soluble sugars [90]. Further studies are needed on osmotic adjustment in reproductive organs to fully understand this mechanism in cotton plants under drought.

Biochemical and molecular mechanisms of drought tolerance

Plants avoid a range of external stresses through morphological adaptation. The mechanism of drought tolerance is linked to several biochemical, morpho-physiological, and molecular processes. These processes are intensely regulated by the hormonal interplay within the plant body.

Abscisic acid (ABA)

Abscisic acid (ABA) is a natural plant stress hormone and controls; stress responses, growth, and reproduction in crop plants. Osmotic stress in plants is related with a degree of drought and low water availability [91], which induces ABA synthesis, and adaptive mechanisms [92]. After stress signals reception by the plasma membrane, abscisic acid synthesis is initiated and occurs in the plastids with the exclusion of xanthoxin transformation to ABA. This occurs in the cytoplasm [93]. ABA is generally synthesized in roots and transported to upper parts of the plant via vascular tissues [94]. In cotton, perception and signal transduction of ABA are facilitated either by ABA-dependent or ABA-independent passageway, where the former is key player in the expression of stress-responsive gene during numerous stresses, particularly under osmotic stress. Numerous receptors have been recognized in plasma membrane, cytosol, chloroplast envelope and nucleus. Under non-stress environment, plants show low ABA content and sucrose non-fermenting 1-linked protein kinase 2 (SnRK2) proteins action is subdued via protein phosphatase 2C (PP2C), which results in dephosphorylation. In cotton plants, ABA improves drought tolerance by regulation of stress-associated gene. Overexpression of ABA-induced cotton gene GhCBF3 in Arabidopsis led to drought resistance in transgenic lines through maintaining higher relative water levels, chlorophyll and proline content than wild type [95]. Compared with wild type transgenic line, AREB1 and AREB2 show higher expression levels, while lower stomatal aperture upon treated with ABA. Suggesting that, GhCBF3 can improve drought resistance through ABA signaling pathway.

Jasmonic acid (JA)

Jasmonic acid (JA) is regarded plant phytohormone and its active derivatives termed jasmonates. It plays a key role in combating several biotic and abiotic stresses. Furthermore, better root structure, tendril coiling, pollen production and fruit ripening are associated with JA [96]. Studies reported that exogenously applied jasmonates increases plant performance under arid environments [97] and regulate stomatal dynamics [98]. Jasmonic acid signaling pathway and biosynthesis have been widely studied [99]. The jasmonate-zim domain (JAZ) repressor protein plays significant roles in the JA signaling pathway which perform as a switch for JA signaling. Under non-stress environment and absence of JA, jasmonate-insensitive/jasmonate-zim (JAI3/JAZ) proteins link to numerous transcription aspects including myelocytomatosis (MYC2) and suppress their activity. Nevertheless, under deficit water, when JA and its derivatives are present, degradation of JAZ proteins happens as depicted above, causing active transcription factors i.e. MYC2, that up-regulate genes associated with stress tolerance [100]. Usually, plant hormones do not perform in single pathways, but somewhat depended on each other at various phases to regulate ambient and developmental pathways. In plants, signal transduction arises and can organize numerous developments to respond to harsh environment in a complicated way [98].

Reactive oxygen species (ROS)

Fractional reduction of atmospheric O2 causes the generation of reactive oxygen species (ROS) also called active reactive oxygen intermediates (ROI). Cellular ROS is composed of four categories i.e. the hydroxyl radical (HO·), superoxide anion radical (O2), hydrogen peroxide (H2O2), and singlet oxygen (1O2). HO· and 1O2 are relatively more reactive and can oxidize DNA, and RNA, lipids and proteins, ultimately causes cell death [101]. Sub-cellular sites, i.e. cell wall, chloroplast, nucleus, mitochondria and plasma membrane, induces ROS production [102]. Production of these ROS raises under drought e.g. a reduction in CO2 fixation results in diminished NADP+ redevelopment during the Calvin cycle. This decreases photosynthetic electron transport chain the activity. Furthermore, too much electrons leakage to O2 by the Mehler reaction in drought-treated cells can also improve ROS production during photosynthesis [103]. The Mehler reaction lessens O2 to O2− by donation of an electron in photosystem I. O2− can be transformed to hydrogen peroxide by superoxide dismutase which can be further transformed to water by ascorbate peroxidase [104]. Nevertheless, it is hard to assess the levels of ROS generated during the Mehler reaction relative to those produced via photorespiration. Moisture stress also increases the photorespiratory pathway, principally when RuBP oxygenation is high owing to partial CO2 fixation. Approximately 70% of the total H2O2 production under moisture stress takes place via photorespiration [105].

Plants have complex scavenging mechanisms and controlling pathways to screen ROS redox homeostasis to avoid additional ROS in cells. In cotton plants, changes in antioxidant enzyme metabolism can affect drought resistance. The antioxidant systems have been developed by plants to continue their growth. This system is composed of enzymatic and non-enzymatic complements. These enzymes are superoxide dismutase, ascorbate peroxidase, guaiacol peroxidas, monodehydroascorbate reductase, catalas, dehydroascorbate reductase and glutathione reductase. Reduced ascorbic acid (AA), flavonoids, carotenoids, proline, glutathione and (GSH), α-tocopherol are the non-enzymatic constituents. These two constituents act together to scavenge ROS [106, 107]. Ascorbate peroxidase, combine with NADH MDAR, and GR, detoxify H2O2 through the Halliwell–Asada pathway [107]. Ascorbate reduces MDHA to MDHAR. Nevertheless, 2 molecules of MDHA can be non-enzymatically transformed to MDHA and dehydroascorbate, which is further reduced to ascorbate through the NADH and GR cycle [108]. Glutathione (GSH) is reduced by GR oxidation at the presence of NADPH. Glutathione reductase activity increases under moisture stress to retain oxidized and reduced glutathione ratios at certain levels [109]. The equilibrium between antioxidative enzyme activities and ROS production decides, if oxidative signaling and/or loss occur [110]. The antioxidative ability of different cotton cultivars regulates the resistance potential to dry conditions. In cotton, moisture stress induces ROS production, but in contrast, the APX and GR activities can also improve and sustain the ROS scavenging process [111]. Nutrient (Zn) application have been found to minimize polyethylene glycol (PEG)-induced oxidative damages in cotton. This increases CAT, APX, SOD, activities and non-enzymatic antioxidants content [112]. Zhang et al. [111] found in a drought-tolerant (CCRI-60) cotton line has led to increased GR activity and improved proline level. Compared with the sensitive (CCRI-27) CCRI-60 had potential to scavenge free radicals and protect the plants from harsh conditions. As a result, indicating improved growth and induced tolerance in response to drought stress. Down-regulation of GbMYB5 in G. barbadense led to reduced antioxidant enzyme activities include CAT, peroxidase (POD), SOD, and glutathione S-transferase (GST), and enhanced oxidative stress when exposed to moisture stress [113]. However, further investigations are needed to identify genes involved in the antioxidant enzyme-related pathways in drought resistant cotton cultivars. Additionally, application of Zn and K supplies can also improve the antioxidant system of cotton plants [107114].

Strategies to improve drought tolerance

Globally, numerous management strategies are implemented for better crop production under stressful environments. The combined application of various management options is critical due to agricultural, financial, social and ecological limitations. Among these, nutrients management is regarded a quick and more effective better strategy to tackle abiotic stresses. Incremental transformations in cotton productivity are important, particularly in arid regions due to limited soil water availability. In this context, cotton crop that demand a lesser amount of water but produce optimal yields and good quality fiber will be more necessary. Despite the traditional breeding programs, improvement in biotechnology can harvest desirable cotton crops that produces optimal yields in the current and future harsh environmental conditions. Exogenous use of growth regulators, soil amendments, specific osmoprotectants, and essential nutrients can enhance drought resistance in vulnerable plants.

Exogenous application of substances

Application of hydrogels

Hydrogels are super absorbent polymers and possess the potential to retain substantial quantity of water. Utilization of these substances in many industrial and environmental zone may be possible [115]. In agriculture, water retention capacity of soil can be enhanced by the addition of hydrogels. Cellulose, pectin, chitin and carboxymethyl cellulose (CMC), are the natural macro-molecules having high potential to absorb water to form hydrogels. They swell quickly and hold enormous amount of water in three-dimensional structure, when placed in water [116]. In controlled release systems, the utilization of hydrogels since the availability of suitable nutrients in soil is an aspect for crops productivity [117]. Furthermore, existence of hydrogels in the soil increases water availability and decreases nutrients loss by percolation and leaching. Enhancement of soil aeration and drainage, and a faster rate of plant root and shoot growths [107]. In conclusions, use of hydrogels enhances soil water retention capacity and water uptake. Hydrogels can improve plants performance by enhancing soil permeability, infiltration rates, reducing irrigation frequency, decreasing soil erosion and lessen water loss.

Appropriate and adequate fertilization

Maintenance of adequate potassium (K) nutrition to plants has been found critical to mitigate drought stress. Potassium is the most important plant macro-nutrient with regard to cotton water relations, and it influences plant biochemical and physiological processes regulating to development and metabolism [118]. Compared to control conditions, K fertilization can significantly improve cotton yield and yield contributors under stress (Table 1).
Table 1

Effect of short-duration drought stress and recovery after re-watering at flowering stage on seed cotton yield (SCY) and its components in two different cotton cultivars under different K rates

Cultivar

Water regime

K level

Number of bolls/plant

Boll weight (g)

SCY/plant (g)

Siza 3

Control

0

14.6c

4.9c

71.41c

  

150

16.8b

5.5a

93.20b

  

300

18.2a

5.7a

103.15a

 

Stress

0

7.6f

4.5d

35.94e

  

150

11.3e

5.2b

58.68d

  

300

12.9d

5.5a

67.98c

Simian 3

Control

0

16.1b

4.6cd

74.25c

  

150

17.6a

4.9b

86.22b

  

300

18.6a

5.2a

95.86a

 

Stress

0

8.8e

4.2e

38.09f

  

150

11.4d

4.5d

50.34e

  

300

13.0c

4.7c

58.55d

For each cultivar, values followed by a different letter within the same column are significantly different at P ≤ 0.05 probability level. Each value represents the mean of three replications [114]

ROS generation in drought stressed crops may further be increased when combined with K deficiency [119]. CO2 fixation in K-stressed plants greatly restricted by impairment in stomata regulation when subjected to drought. Under drought, in plant cells increasing extra-chloro-plastic K+ concentrations with surplus application of K+ could prevent photosynthesis inhibition under moisture stress [120]. An adaptive K demand for drought subjected plants may be associated to the role of K in enhancing photosynthetic CO2 fixation and transport of photosynthates to sink. By this way inhibiting the transfer of photosynthetic electrons to O2 resulting in low ROS production [119]. A recent study demonstrated that K fertilizer application induced drought tolerance in cotton plant by improving leaf photosynthetic capacity, biomass accumulation and enhanced down-stream carbohydrate metabolism [120]. In summary, an adequate K supply can increase cell membrane stability, leaf area, root growth, and final biomass for drought stressed plants and also improves water uptake. This indicate that, appropriated K nutrition is important for plant osmotic adjustment and alleviating ROS impairment. The potential roles of K in plants exposed to drought stress are presented in (Fig. 3).
Fig. 3
Fig. 3

The relationship between potassium supply and morpho-physiological characteristics in response to water deficit conditions in cotton crops

Growth regulators

Both, natural and synthetic plant growth regulators can reduce the adverse effects of deteriorated environmental conditions on plant development. Foliar application of growth regulators and osmoprotectants can also improve drought resistance in cotton. Exogenous application of osmoprotectants and plant hormones such as salicylic acid (SA), proline, ABA, glycinebetaine, polyamines and gibberellic acid (GA3) have been found to induce moisture stress tolerance. In plants, these hormones, elevated osmotic adjustment to increase turgor pressure and enhance addition of antioxidants to detoxify ROS; sustaining the integrity of membrane structures and macromolecules under moisture stress environment [121]. Glycine betaine and proline have been reported effective in minimizing the negative impacts of water stress on cotton. Similarly, exogenous GA use can enhance leaf photosynthetic capacity, stomata conductance and transpiration rate of cotton crop [122].

Molecular basis of drought tolerance

Tolerance to water stress is a quantitatively controlled trait in plants. Drought changes the expression of genes, regulating water transport, oxidative damage, osmotic balance and damage repair mechanism. Recently developed molecular tools e.g. RNA-Seq and bio-informatic have accelerated the discovery of stress responsive genes in many plant species. For example, 33 QTLs have been identified in F3 plants originated from a cross between G. barbadense and G. hirsutum for water deficit conditions, including 5, 11 and 17 QTLs for physiological traits, plant productivity and fiber quality, respectively [123]. Most of the identified QTLs for drought tolerance were located on c2, 6 and 14 chromosomes [53]. Levi et al. [124] used marker-assisted selection for generating near-isogenic lines with greater drought tolerance and yield potential from the G. barbadense and G. hirsutum hybrids. Further, the G. hirsutum plants displayed greater levels of metabolites and more stable photosynthesis compared with G. barbadense under drought and well water conditions [124]. Similarly, QTLs related to osmotic potential (on chromosome c1, c2, 6 and 25), chlorophyll (on c2 and c14) and leaf morphology have been identified in drought tolerant cotton genotypes. In addition, 15 markers were found related to drought tolerance in 323 G. hirsutum genotypes with the help of microsatellite markers. Out of these, 12 markers showed negative and the remaining showed positive allele effects for drought tolerance [125]. Likewise, Zheng et al. [123] identified 11 physiological and morphological marker traits linked with drought tolerance in the field-grown cotton crop, while 67 and 35 QTLs were expressed under water drought and non-drought environment, respectively. These QTLs were mainly located on chromosome c16, c9 and c2.

Role of miRNAs in drought stress alleviation

MicroRNAs (miRNAs), a class of endogenous non-coding small RNAs molecules, play an imperative role in response to several abiotic stresses [126]. For instance, hormone mediated signaling cross talk in crops was involved in combating drought stress, i.e. abscisic, ethylene and salicylic acid [127]. In plant, gene expression and hormonal regulation is an effective strategy to combat drought [128] which are in turn are controlled by miRNAs. Drought stress responsive miRNAs are shown to participate in various crops species like Arabidopsis [129], rice [130], cotton [131] and Brassica napus [132]. The role of miRNAs under drought stress have been presented (Fig. 4). In the current agricultural systems, scientists are paying more attention to improve lint yield and quality and the mechanisms of fiber development and adaptation of drought [133]. Exposure to long term water deficit conditions can cause in serious metabolic disorders in cotton plants leading to tissue dehydration, ionic toxicity and nutritional imbalance [134]. In cotton over-expression of GhCIPK6 gene improved drought resistance. This indicates that it could be a helpful to combat moisture stress in cotton [135]. Transgenic tobacco overexpression of the C mitogen-activated protein kinase gene (GhMPK2) in cotton group resulted in lower water with greater resistance to drought. This indicates that GhMPK2 might be positively adjusts drought resistance in cotton [136]. A sequence of cotton miRNAs is associated with genes, such as miR172, miR6158, miR396, miR164, ghr-n56, ghr-n59, ghr-n24 and miR1520. Interestingly, 163 cotton miRNAs were explored to target 210 genes associated with fiber development [131]. In brief, miRNAs are novel tool to improve plant performance under harsh environmental conditions. More studies on the function and expression of these miRNAs will be needed to explain their regulatory role in inducing tolerance to harsh environments.
Fig. 4
Fig. 4

Different cellular processes in association with miRNAs for drought tolerance in plants

Transgenic approach

At molecular level, plants respond to abiotic stresses by altering expression of genes that in turn regulate protein synthesis and biological functions [137]. Regulation of these genes imparted stress response is an essential factor in plants that enhance plants growth and development under abiotic stresses. Various pathways associated with drought tolerance have been identified in transgenic cotton cultivars under controlled and field (Table 2). Out of thousands of identified genes, only fewer genes were associated with drought tolerance. Various genes, regulating response of Pima cotton (G. barbadense) to stressed environments e.g. drought, salt, heat, cold, and phosphorus deficiency have been identified using normalized cDNA libraries [138]. These desired traits may be transferred to upland cotton (G. hirsutism) through intraspecific breeding or genetic engineering techniques [139]. For example, transfer of genes from Thellungiella halophile overexpressing TsVP, an H+-PPase into cotton genotypes enhanced shoot and root growth than wild type. This improved performance of transgenic lines was the result of higher leaf chlorophyll level; photosynthesis efficiency, water content and cellular thermos-stability. Improved root structure and lower solute potential of transgenic plants enabled transgenic cotton to produce 51% more seed cotton than the wild type cotton [140]. Transfer of ScALDH21 gene from Syntrichia carninervis induced drought tolerance in cultivated cotton [141]. At natural environment, transgenic lines produced greater biomass, bigger bolls and fiber yield relative to the wild type under drought stress. This superior performance of transgenic cotton was achieved through improved physiological traits e.g. higher proline and soluble sugars, photosynthesis and lower lipid peroxidation. These discoveries have encouraged scientists to engineer water deficit resistance crops (cotton) through genetic engineering technology. As a result, various desired genes have been transferred into cotton plants. However, field validation of these transgenic plants is still needed as most of these experiments have been performed under controlled environments and did not produce significant results in the field.
Table 2

Successful stories of GM plants against drought stress

Environmental condition

Stress type

Beneficial features for drought tolerance

Yield

References

Greenhouse and field

Drought

Improved water use efficiency (WUE), photosynthesis, root system and osmotic adjustment and scavenging ROS

NA

[142]

Laboratory and green house

Drought and heat

Enhanced protection of photosynthesis, seedlings and leaf viability

NA

[137]

Laboratory, greenhouse and field

Drought and salt

Increased proton pump activity of the vacuolar pyrophosphatase, auxin polar transport stimulation lead to root development

Increased 20%

[143]

Laboratory and greenhouse

 

High chlorophyll content, improved photosynthesis, higher relative water content and less cell membrane damage

Increased 40%

[140]

Laboratory, greenhouse and field

Drought

Increased production of ABA and proline content

NA

[144]

Green house

 

Enhanced proline content and root development, while transpiration rate decreased

131% more bolls

[145]

Green house and field

Drought and salt

Enhanced sequestration of ions and sugars into vacuole, reduced water potential, and enhanced root biomass

20% increased

[146]

Greenhouse

Drought

Higher relative water content and proline level while reduced H2O2, lipid peroxidation and electrolyte leakage

57.6%, more bolls

[147]

Greenhouse

Drought

Improved photosynthesis, roots and shoots, higher relative water content and less cell membrane damage

51% higher

[88]

Greenhouse

Drought

Increased photosynthesis, higher relative water content, better osmotic adjustment, less ion leakage and lipid membrane peroxidation

3–12% more

[148]

Greenhouse

Drought

Higher photosynthesis, delayed leaf senescence

NA

[149]

Greenhouse

Drought and salt

Longer roots, higher chlorophyll and proline content, higher germination rate and soluble sugar, lower lipid peroxidation

NA

[150]

Greenhouse

Drought

Higher soluble sugar and proline content, enhanced superoxide dismutase and peroxidase, improved cell membrane integrity, increased net photosynthesis, stomatal conductance, transpiration rate and root length

NA

[150]

Laboratory green house and field

Drought and salt

Increased proline and soluble sugar content, well developed roots, reduced leaf stomatal density, increase ROS scavenging enzymes

43% higher

[144]

Green house and field

Drought

Proline content and sugar increased, higher peroxidase activity, reduced loss of net photosynthetic rate, reduced lipid peroxidation, greater plant height, larger bolls

Yield increased

[141]

CRISPR/Cas9 technology

In recent years, zinc finger nuclease (ZFN) and clustered regularly interspaced short palindromic repeat (CRISPR) has become a popular genome editing technology. This technology is highly important for creating genetically engineered plants as well as functional genomic study. These systems are associated with (Cas) 9 proteins and guide RNA (gRNA) is a rapidly developing genome editing technology which is effectively employed in many plants [151] such as rice [152], Arabidopsis [153], potato [154], watermelon [155], maize [156], tomato [157] and soybean [158]. Cas9 is composed of two nuclease domains in which the largely used one is resulted in from streptococcus pyogenes. The gRNA: is a synthetic 100 nucleotide (nt) RNA molecule. The first about 20 nt are the targeting site and the 3′end forms a hairpin structure that interacts with Cas9 protein [159]. A distinctive feature of CRISPR/Cas9 is that DNA cleavage sites are recognized through Watson–Crick base pairing [160] by three components: Cas9 protein, CRISPR-RNA (crRNA) and trans-activating crRNA (trancrRNA) [161]. The utilization of CRISPR/Cas9 system as a genome engineering tool came out when it was revealed that the target DNA sequence could be simply re-programmed by altering 20 nucleotides in the CRISPR-RNA [159]. In cotton, the application of CRISPR/Cas9 is still at its infancy. Most recently, multiple sites genome editing through CRISPR/Cas9 system in allotetraploid cotton by targeting arginase (GhARG), discosoma red fluorescent protein2 (DsRed2) and chloroplast development (GhCLA1) genes suggests that it is highly reliable and effective for cotton genome editing [162]. The ZFN is a laborious method because of complications in protein design, synthesis, and validation [163]. These issues were resolved with the exploration of CRISPR/Cas9 system, which saves time and cost, and is highly efficient [158]. The CRISPR/Cas9 system functions as an endonuclease and it induces double-strand breaks (DSB) at specific genome sites. In eukaryotic cells, such breaks are preferentially restored by the error-prone NHEJ (non-homologous 98 ends joining) pathway and often causes bases insertion, deletion resulting in gene function loss [164]. In plants, DSBs could be employed to knock-out genes [165], modify expression of gene by insert transgenes at a certain location via homologous recombination [166] or disrupting promoter sequences [167]. Considering the reported data about CRISPR technology; it will be a simple, time saving, cost effective and highly effective tool for plant gene expression, repression and genome editing. Thus, encouraging the application of genome editing tool to yield new alleles and engineer plants possessing required quality, agronomic traits and good drought tolerance. It is predictable that the possible applications of CRISPR/Cas9 in cotton genome editing are certain to be further established over time. In the future, advancements will continue to enhance their use from mutant generation to precise gene regulation at noncoding enhancer regions in cotton.

Conclusions and future research directions

Sustainable crop production is a key goals of the current agricultural production systems. Drought is a major abiotic stress, limiting crop productivity in many parts of the world. Restricted water supply to cotton plants can impair normal physiological functioning through reduced nutrient supply and cellular toxicity. Therefore, improving crop performance under harsh environments has become an increasingly important issue. Despite major advances in genetic approaches, challenges to crop production in terms of genetic and environmental interactions for cotton lint production are still not fully understood. To date, limited data is available regarding the role of CRISPR/Cas9 technology, ascorbic acid, calcium, hydrogel application and the miRNAs under drought stress in cotton crops. There are still issues with the transgenic crops produced for inducing drought tolerance. Further, many transgenic plants have not been verified under natural conditions. Therefore, the performance under natural environment is still a question mark. Up to date information regarding drought-associated genes and their functions is poorly understood in cotton crops. Further research is inevitable to study these genes in response to drought stress under natural conditions as well as drought associated cotton protein kinases. Further research is needed for enhancing crop productivity under drought stress through interference (RNAi) technology. Cas9 will develop novel alleles, desirable agronomic and quality traits through engineer plants and will produce tolerance in crops plants against drought stress and or harsh environmental conditions.

Notes

Abbreviations

CRISPR/Cas9: 

clustered regularly interspaced short palindromic repeat

Pn

photosynthetic rate

Pro: 

proline

ABA: 

abscisic acid

SnRK2: 

sucrose non-fermenting 1-linked protein kinase 2

PP2C: 

protein phosphatase 2C

JA: 

jasmonic acid

JAZ: 

jasmonate-zim domain

JAI3/JAZ: 

jasmonate-insensitive/jasmonate-zim

MYC2: 

myelocytomatosis

MYC2: 

myelocytomatosis

ROI: 

active reactive oxygen intermediates

HO·: 

hydroxyl radical

O2

superoxide anion radical

H2O2

hydrogen peroxide

1O2

singlet oxygen

AA: 

ascorbic acid

GSH: 

glutathione

GSH: 

glutathione

PEG: 

polyethylene glycol

CAT: 

catalyse

SOD: 

super oxide dismutase

POD: 

peroxidase

GST: 

glutathione S-transferase

CMC: 

carboxymethyl cellulose

SA: 

salicylic acid

GA3

gibberellic acid

miRNAs: 

microRNAs

ZFN: 

finger nuclease

gRNA: 

guide RNA

Declarations

Authors’ contributions

AK, XP, and LH conceived the idea of the review and prepared the initial outline and wrote the first draft. AK and XP had major and equal contribution in overall preparation of manuscript. UN, DKYT, SF, and RZ revised the manuscript. All authors read and approved the final manuscript.

Acknowledgements

This work was supported by the National Natural Science Foundation of China (31760355).

Competing interests

The authors declare that they have no competing interests.

Availability of supporting data

Not applicable.

Consent for publication

Not applicable.

Ethics approval and consent to participate

Not applicable.

Funding

We are thankful the National Natural Foundation of China for their financial support.

Publisher’s Note

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Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

Authors’ Affiliations

(1)
The Key Laboratory of Oasis Eco-agriculture, Xinjiang Production and Construction Group, Shihezi University, Shihezi, 832003, People’s Republic of China
(2)
Key Laboratory of Plant Genetic and Breeding, College of Agriculture, Guangxi University, Nanning, 530005, People’s Republic of China
(3)
Queensland Alliance for Agriculture and Food Innovation, Centre for Plant Science, The University of Queensland, Toowoomba, QLD, 4350, Australia
(4)
Plant Breeding Institute, Sydney Institute of Agriculture, School of Life and Environmental Faculty of Science, The University of Sydney, Sydney, NSW, 2006, Australia
(5)
Department of Plant Sciences and Technology, Huazhong Agriculture University, Wuhan, 430000, People’s Republic of China
(6)
Department of Agronomy, The University of Swabi, Swabi, Pakistan
(7)
College of Life Science, Linyi University, Linyi, 276000, Shandong, China
(8)
Key Laboratory of Crop Growth Regulation, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, 210095, People’s Republic of China

References

  1. Fahad S, Bano A. Effect of salicylic acid on physiological and biochemical characterization of maize grown in saline area. Pak J Bot. 2012;44:1433–8.Google Scholar
  2. Peng S, Huang J, Sheehy JE, Laza RC, Visperas RM, Zhong X, Cassman KG. Rice yields decline with higher night temperature from global warming. Proc Natl Acad Sci. 2004;101(27):9971–5.View ArticleGoogle Scholar
  3. Fahad S, Hussain S, Saud S, Hassan S, Chauhan BS, Khan F, Ihsan MZ, Ullah A, Wu C, Bajwa AA, Alharby H, Amanullah, Nasim W, Shahzad B, Tanveer M, Huang J. Responses of rapid viscoanalyzer profile and other rice grain qualities to exogenously applied plant growth regulators under high day and high night temperatures. PLoS ONE. 2016;11(7):e0159590. https://doi.org/10.1371/journal.pone.0159590.View ArticlePubMedPubMed CentralGoogle Scholar
  4. Fahad S, Hussain S, Saud S, Khan F, Hassan S Jr, Nasim W, Arif M, Wang F, Huang J. Exogenously applied plant growth regulators affect heat-stressed rice pollens. J Agron Crop Sci. 2016;202:139–50.View ArticleGoogle Scholar
  5. Fahad S, Hussain S, Saud S, Hassan S, Ihsan Z, Shah AN, Wu C, Yousaf M, Nasim W, Alharby H, Alghabari F, Huang J. Exogenously applied plant growth regulators enhance the morphophysiological growth and yield of rice under high temperature. Front Plant Sci. 2016;7:1250. https://doi.org/10.3389/fpls.2016.01250.View ArticlePubMedPubMed CentralGoogle Scholar
  6. Fahad S, Hussain S, Saud S, Hassan S, Tanveer M, Ihsan MZ, Shah AN, Ullah A, Nasrullah KF, Ullah S, AlharbyH NW, Wu C, Huang J. A combined application of biochar and phosphorus alleviates heat-induced adversities on physiological, agronomical andquality attributes of rice. Plant Physiol Bioch. 2016;103:191–8.View ArticleGoogle Scholar
  7. Fahad S, Chen Y, Saud S, Wang K, Xiong D, Chen C, Wu C, Shah F, Nie L, Huang J. Ultraviolet radiation effect on photosynthetic pigments, biochemical attributes, antioxidant enzyme activity and hormonal contents of wheat. J Food Agric Environ. 2013;11(3&4):1635–41.Google Scholar
  8. Fahad S, Hussain S, Bano A, Saud S, Hassan S, Shan D, Khan FA, Khan F, Chen Y, Wu C, Tabassum MA, Chun MX, Afzal M, Jan A, Jan MT, Huang J. Potential role of phytohormones and plant growth-promoting rhizobacteria in abiotic stresses: consequences for changing environment. Environ Sci Pollut Res. 2015;22(7):4907–21.View ArticleGoogle Scholar
  9. Fahad S, Hussain S, Matloob A, Khan FA, Khaliq A, Saud S, Hassan S, Shan D, Khan F, Ullah N, Faiq M, Khan MR, Tareen AK, Khan A, Ullah A, Ullah N, Huang J. Phytohormones and plant responses to salinity stress: a review. Plant Growth Regul. 2015;75(2):391–404. https://doi.org/10.1007/s10725-014-0013-y.View ArticleGoogle Scholar
  10. Fahad S, Hussain S, Saud S, Tanveer M, Bajwa AA, Hassan S, Shah AN, Ullah A, Wu C, Khan FA, Shah F, Ullah S, Chen Y, Huang J. A biochar application protects rice pollen from high-temperature stress. Plant Physiol Biochem. 2015;96:281–7.View ArticleGoogle Scholar
  11. Fahad S, Nie L, Chen Y, Wu C, Xiong D, Saud S, Hongyan L, Cui K, Huang J. Crop plant hormones and environmental stress. Sustain Agric Rev. 2015;15:371–400.View ArticleGoogle Scholar
  12. Fahad S, Bajwa AA, Nazir U, Anjum SA, Farooq A, Zohaib A, Sadia S, Nasim W, Adkins S, Saud S, Ihsan MZ, Alharby H, Wu C, Wang D, Huang J. Crop production under drought and heat stress: plant responses and management options. Front Plant Sci. 2017;8:1147. https://doi.org/10.3389/fpls.2017.01147.View ArticlePubMedPubMed CentralGoogle Scholar
  13. Fahad S, Muhammad ZI, Abdul K, Ihsanullah D, Saud S, Saleh A, Nasim W, Muhammad A, Imtiaz AK, Chao W, Depeng W, Huang J. Consequences of high temperature under changing climate optima for rice pollen characteristics-concepts and perspectives. Arch Agron Soil Sci. 2018. https://doi.org/10.1080/03650340.2018.1443213.View ArticleGoogle Scholar
  14. Wu C, Cui K, Wang W, Li Q, Fahad S, Hu Q, Huang J, Nie L, Mohapatra PK, Peng S. Heat-induced cytokinin transportation and degradation are associated with reduced panicle cytokinin expression and fewer spikelets per panicle in rice. Front Plant Sci. 2017;8:371. https://doi.org/10.3389/fpls.2017.00371.View ArticlePubMedPubMed CentralGoogle Scholar
  15. Naeem M, Muhammad SN, Rashid A, Muhammad ZI, Muhammad YA, Yasir H, Fahad S. Foliar calcium spray confers drought stress tolerance in maize via modulation of plant growth, water relations, proline content and hydrogen peroxide activity. Arch Agron Soil Sci. 2017;1:1. https://doi.org/10.1080/03650340.2017.1327713.View ArticleGoogle Scholar
  16. Saud S, Fahad S, Yajun C, Ihsan MZ, Hammad HM, Nasim W, Jr Amanullah, Arif M, Alharby H. Effects of nitrogen supply on water stress and recovery mechanisms in Kentucky bluegrass plants. Front Plant Sci. 2017;8:983. https://doi.org/10.3389/fpls.2017.00983.View ArticlePubMedPubMed CentralGoogle Scholar
  17. Saud S, Chen Y, Long B, Fahad S, Sadiq A. The different impact on the growth of cool season turf grass under the various conditions on salinity and draught stress. Int J Agric Sci Res. 2013;3:77–84.Google Scholar
  18. Saud S, Li X, Chen Y, Zhang L, Fahad S, Hussain S, Sadiq A, Chen Y. Silicon application increases drought tolerance of Kentucky bluegrass by improving plant water relations and morphophysiological functions. Sci World J. 2014. https://doi.org/10.1155/2014/368694.View ArticleGoogle Scholar
  19. Saud S, Chen Y, Fahad S, Hussain S, Na L, Xin L, Alhussien SAAFE. Silicate application increases the photosynthesis and its associated metabolic activities in Kentucky bluegrass under drought stress and post-drought recovery. Environ Sci Pollut Res. 2016;23(17):17647–55. https://doi.org/10.1007/s11356-016-6957-x.View ArticleGoogle Scholar
  20. Comas LH, Becker SR, Cruz VMV, Byrne PF, Dierig DA. Root traits contributing to plant productivity under drought. Front Plant Sci. 2013;4:442. https://doi.org/10.3389/fpls.2013.00442.View ArticlePubMedPubMed CentralGoogle Scholar
  21. Khan A, Tan DKY, Afridi MZ, Luo H, Tung SA, Ajab M, Fahad S. Nitrogen fertility and abiotic stresses management in cotton crop: a review. Environ Sci Pollut Res. 2017;24:14551–66. https://doi.org/10.1007/s11356-017-8920-x.View ArticleGoogle Scholar
  22. Wang R, Gao M, Ji S, Wang S, Men Y, Zhou Z. Carbon allocation, osmotic adjustment, antioxidant capacity and growth in cotton under long-term soil drought during flowering and boll-forming period. Plant Physiol. Biochem. 2016;107:137.View ArticleGoogle Scholar
  23. Zahoor R, Dong H, Abid M, Zhao W, Wang Y, Zhou Z. Potassium fertilizer improves drought stress alleviation potential in cotton by enhancing photosynthesis and carbohydrate metabolism. Environ Exp Bot. 2017;137:73–83. https://doi.org/10.1016/j.envexpbot.2017.02.002.View ArticleGoogle Scholar
  24. Broughton KJ, Bange MP, Duursma RA, Payton P, Smith RA. The effect of elevated atmospheric [CO2] and increased temperatures on an older and modern cotton cultivar. Funct Plant Biol. 2017;44:22. https://doi.org/10.1071/fp17165.View ArticleGoogle Scholar
  25. Berry P, Ramirezvillegas J, Bramley H, Mgonja MA, Mohanty S. Regional impacts of climate change on agriculture and the role of adaptation. Int J Gynecol Obstet. 2013;119(Suppl 3):S579.Google Scholar
  26. Ashraf M. Inducing drought tolerance in plants: recent advances. Biotchnol Adv. 2010;28:169–83. https://doi.org/10.1016/j.biotechadv.2009.11.005.View ArticleGoogle Scholar
  27. Cai X, Molden D, Mainuddin M, Sharma B, Mohyddin A, Karini P. Producing more food with less water in the changing world: assessment of water productivity in 10 major river basins. Water Intl. 2013;36:421–62. https://doi.org/10.1080/02508060.2011.542403.View ArticleGoogle Scholar
  28. Khan A, Wang L, Ali S, Tung SA, Hafeez A, Yang G. Optimal planting density and sowing date can improve cotton yield by maintaining reproductive organ biomass and enhancing potassium uptake. Field Crop Res. 2017;214:164–74. https://doi.org/10.1016/j.fcr.2017.09.016.View ArticleGoogle Scholar
  29. Loka DM, Derrick M, Oosterhuis, Ritchie GL. Water-deficit stress in cotton. In: Oosterhuis DM, eds. Stress physiology in cotton. Number Seven The Cotton Foundation Book Series. 2011. p. 37–72.Google Scholar
  30. Fang Y, Liao K, Du H, Xu Y, Song H, Li X, Xiong L. A stress-responsive NAC transcription factor SNAC3 confers heat and drought tolerance through modulation of reactive oxygen species in rice. J Exp Bot. 2015;66:6803–17. https://doi.org/10.1093/jxb/erv386.View ArticlePubMedPubMed CentralGoogle Scholar
  31. Luo LJ. Breeding for water-saving and drought-resistance rice (WDR) in China. J Exp Bot. 2010;61:3509–17. https://doi.org/10.2307/24038852.View ArticlePubMedGoogle Scholar
  32. Manavalan LP, Guttikonda SK, Tran LSP, Nguyen HT. Physiological and molecular approaches to improve drought resistance in soybean. Plant Cell Physiol. 2009;50:1260–76. https://doi.org/10.1093/pcp/pcp082.View ArticlePubMedGoogle Scholar
  33. Zhang H, Khan A, Tan DKY, Luo H. Rational water and nitrogen management improves root growth, increases yield and maintains water use efficiency of cotton under mulch drip irrigation. Front Plant Sci. 2017;8:912. https://doi.org/10.3389/fpls.2017.00912.View ArticlePubMedPubMed CentralGoogle Scholar
  34. Luo HH, Tao XP, Hu YY, Zhang YL, Zhang WF. Response of cotton root growth and yield to root restriction under various water and nitrogen regimes. J Plant Nutr Soil Sci. 2015;178:384–92. https://doi.org/10.1002/jpln.201400264.View ArticleGoogle Scholar
  35. Hulugalle NR, Broughton KJ, Tan DKY. Fine root production and mortality in irrigated cotton, maize and sorghum sown in vertisols of northern New South Wales, Australia. Soil Till Res. 2015;146:313–22. https://doi.org/10.1016/j.still.2014.10.004.View ArticleGoogle Scholar
  36. Gibbs J, Review Greenway H. Mechanisms of anoxia tolerance in plants. I. Growth, survival and anaerobic catabolism. Funct Plant Biol. 2003;30:1–47. https://doi.org/10.1071/pp98095.View ArticleGoogle Scholar
  37. Luo HH, Zhang YL, Zhang WF. Effects of water stress and rewatering on photosynthesis, root activity, and yield of cotton with drip irrigation under mulch. Photosynthetica. 2016;54:65–73. https://doi.org/10.1007/s11099-015-0165-7.View ArticleGoogle Scholar
  38. Ahoor R, Zhao W, Abid M, Dong H, Zhou Z. Potassium application regulates nitrogen metabolism and osmotic adjustment in cotton (Gossypium hirsutum L.) functional leaf under drought stress. J Plant Physiol. 2017;215:30–8. https://doi.org/10.1016/j.jplph.2017.05.001.View ArticleGoogle Scholar
  39. Galmés J, Flexas J, Savé R, Medrano H. Water relations and stomatal characteristics of Mediterranean plants with different growth forms and leaf habits: responses to water stress and recovery. Plant Soil. 2007;290:139–55. https://doi.org/10.1007/s11104-006-9148-6.View ArticleGoogle Scholar
  40. Abid M, Tian Z, Ataulkarim ST, Cui Y, Liu Y. Nitrogen nutrition improves the potential of wheat (Triticum aestivum L.) to alleviate the effects of drought stress during vegetative growth periods. Front Plant Sci. 2016;7:1. https://doi.org/10.3389/fpls.2016.00981.View ArticleGoogle Scholar
  41. Hearn AB. Water relationships in cotton. Outlook Agric. 1980;15:1–8. https://doi.org/10.1016/j.bbrc.2013.04.080.View ArticleGoogle Scholar
  42. Pettigrew WT. Physiological consequences of moisture deficit stress in cotton. Crop Sci. 2004;44:1265–72. https://doi.org/10.2135/cropsci2004.1265.View ArticleGoogle Scholar
  43. Wendel JF, Cronn RC. Polyploidy and the evolutionary history of cotton. Adv Agron. 2002;78:139–86.View ArticleGoogle Scholar
  44. Baytar AA, Peynircioğlu C, Sezener V, Basal H, Frary A, Frary A, Doğanlar S. Identification of stable QTLs for fiber quality and plant structure in Upland cotton (G. hirsutum L.) under drought stress. Ind Crop Prod. 2018;124:776–86.View ArticleGoogle Scholar
  45. Shen X, Guo T, Zhu W, Zhang X. Mapping fiber and yield QTLs with main epistatic and QTL environment interaction effects in recombinant inbred lines of upland cotton. Crop Sci. 2006;46:61–6.View ArticleGoogle Scholar
  46. Girma K, Teal RK, Freeman KW, Boman RK, Raun WR. Cotton lint yield and quality as affected by applications of N, P, and K fertilizers. J Cotton Sci. 2007;11:12–9.Google Scholar
  47. Singh P. Cotton Breeding. Cuttack: Kalyani Publishers, Ludhiana New Delhi Noida (U.P.); 2004. p. 295.Google Scholar
  48. Shakoor MS, Malik TA, Azhar FM, Saleem MF. Genetics of agronomic and fiber traits in upland cotton under drought stress. Int J Agric Biol. 2010;12:495–500.Google Scholar
  49. Parekh MJ, Kumar S, Zala HN, Fougat RS, Patel CB, Bosamia TC, Kulkarni KS, Parihar A. Development and validation of novel fiber relevant dbEST–SSR markers and their utility in revealing genetic diversity in diploid cotton (Gossypium herbaceum and G. arboreum). Ind. J Crop Prod Process. 2016;83:620–9.View ArticleGoogle Scholar
  50. Jamshed M, Jia F, Gong J, Palanga KK, Shi Y, Li J, Shang H, Liu A, Chen T, Zhang Z, Cai J, Ge Q, Liu Z, Lu Q, Deng X, Tan Y, Or Rashid H, Sarfraz Z, Hassan M, Gong W, Yuan Y. Identification of stable quantitative trait loci (QTLs) for fiber quality traits across multiple environments in Gossypium hirsutum recombinant inbred line population. BMC Genomics. 2016;17:197.View ArticleGoogle Scholar
  51. Shang L, Wang Y, Wang X, Liu F, Abduweli A, Cai S. Genetic analysis and QTL detection on fiber traits using two recombinant inbred lines and their backcross populations in upland cotton. Genes Genom Genet. 2016;6(9):2717–24.Google Scholar
  52. Saeed M, Guo W, Ullah I, Tabbasam N, Zafar Y, UR.Rahman M, Zhang T. QTL mappin for physiology, yield and plant architecture traits in cotton (Gossypium hirsutum L.) grown under well-watered versus water-stress conditions. Electron J Biotechnol. 2011;14:1–13.Google Scholar
  53. Saranga Y, Menz M, Jiang CX, Wright RJ, Yakir D, Paterson AH. Genomic dissection of genotype × environment interactions conferring adaptation of cotton to arid conditions. Genome Res. 2001;11:1988–95. https://doi.org/10.1101/gr.157201.View ArticlePubMedGoogle Scholar
  54. Paterson AH, Saranga Y, Menz M, Jiang CX, Wright RJ. QTL analysis of genotype × environment interactions affecting cotton fiber quality. Theor Appl Genet. 2003;106:384–96.View ArticleGoogle Scholar
  55. John ME, Crow LJ. Gene expression in cotton (Gossypium hirsutum L.) fiber: cloning of the mRNAs. Proc Natl Acad Sci USA. 1992;89:5769–73.View ArticleGoogle Scholar
  56. Harmer S, Orford S, Timmis J. Characterisation of six a-expansin genes in Gossypium hirsutum (upland cotton). Mol Genet Genomics. 2002;268:1–9.View ArticleGoogle Scholar
  57. Jiang Y, Guo W, Zhu H, Ruan YL, Zhang T. Overexpression of GhSusA1 increases plant biomass and improves cotton fiber yield and quality. Plant Biotechnol J. 2012;10:301–12.View ArticleGoogle Scholar
  58. Li DD, Ruan XM, Zhang J, Wu YJ, Wang XL, Li XB. Cotton plasma membrane intrinsic protein 2s (PIP2s) selectively interact to regulate their water channel activities and are required for fibre development. New Phytol. 2013;199:695–770.View ArticleGoogle Scholar
  59. Bai WQ, Xiao YH, Zhao J, Song SQ, Hu L, Zeng JY, Li XB, Hou L, Luo M, Li DM, Pei Y. Gibberellin overproduction promotes sucrose synthase expression and secondary cell wall deposition in cotton fibers. PLoS ONE. 2014;9:e96537.View ArticleGoogle Scholar
  60. Ashraf J, Zuo D, Wang Q, Malik W, Zhang Y, Abid MA, Song G, et al. Recent insights into cotton functional genomics: progress and future perspectives. Plant Biotechnol J. 2018;16(3):699–713.View ArticleGoogle Scholar
  61. Li XB, Fan XP, Wang XL, Cai L, Yang WC. The cotton ACTIN1 gene is functionally expressed in fibers and participates in fiber elongation. Plant Cell. 2005;17:859–75.View ArticleGoogle Scholar
  62. Sun Z, Wang X, Liu Z, Gu Q, Zhang Y, Li Z, Ke H, Yang J, Wu J, Wu L. Genome-wide association study discovered genetic variation and candidate genes of fibre quality traits in Gossypium hirsutum L. Plant Biotechnol J. 2017;15:982–96.View ArticleGoogle Scholar
  63. Hu H, He X, Tu L, Zhu L, Zhu S, Ge Z, Zhang X. GhJAZ2 negatively regulates cotton fiber initiation by interacting with the R2R3-MYB transcription factor GhMYB25-like. Plant J. 2016;88:921–35.View ArticleGoogle Scholar
  64. Brill E, van Thournout M, White RG, Llewellyn D, Campbell PM, Engelen S, Ruan YL, Arioli T, Furbank RT. A novel isoform of sucrose synthase is targeted to the cell wall during secondary cell wall synthesis in cotton fiber. Plant Physiol. 2011;157:40–54.View ArticleGoogle Scholar
  65. Yang Z, Zhang C, Yang X, Liu K, Wu Z, Zhang X, Zheng W, Xun Q, Liu C, Lu L, Yang Z, Qian Y, Xu Z, Li C, Li J, Li F. PAG1, a cotton brassinosteroid catabolism gene, modulates fiber elongation. New Phytol. 2014;203:437–48.View ArticleGoogle Scholar
  66. Deng F, Tu L, Tan J, Li Y, Nie Y, Zhang X. GbPDF1 is involved in cotton fiber initiation via the core cis-element HDZIP2ATATHB2. Plant Physiol. 2012;158:890–904.View ArticleGoogle Scholar
  67. Ruan YL, Llewellyn DJ, Furbank RT. Suppression of sucrose synthase gene expression represses cotton fiber cell initiation, elongation, and seed development. Plant Cell. 2003;15:952–64.View ArticleGoogle Scholar
  68. Xu WL, Zhang DJ, Wu YF, Qin LX, Huang GQ, Li J, Li L, Li XB. Cotton PRP5 gene encoding a proline-rich protein is involved in fiber development. Plant Mol Biol. 2013;82:353–65.View ArticleGoogle Scholar
  69. Kim HJ, Tang Y, Moon HS, Delhom CD, Fang DD. Functional analyses of cotton (Gossypium hirsutum L.) immature fiber (im) mutant infer that fiber cell wall development is associated with stress responses. BMC Genomics. 2013;14:889.View ArticleGoogle Scholar
  70. Machado A, Wu Y, Yang Y, Llewellyn DJ, Dennis ES. The MYB transcription factor GhMYB25 regulates early fibre and trichome development. Plant J. 2009;59:52–62.View ArticleGoogle Scholar
  71. Loguercio LL, Zhang JQ, Wilkins TA. Differential regulation of six novel MYB-domain genes defines two distinct expression patterns in allotetraploid cotton (Gossypium hirsutum L.). Mol Gen Genet. 1999;261:660–71.View ArticleGoogle Scholar
  72. Suo J, Liang X, Pu L, Zhang Y, Xue Y. Identification of GhMYB109 encoding a R2R3 MYB transcription factor that expressed specifically in fiber initials and elongating fibers of cotton (Gossypium hirsutum L.). Biochim Biophys Acta. 2003;1630:25–34.View ArticleGoogle Scholar
  73. Zhang F, Liu X, Zuo K, Zhang J, Sun X, Tang K. Molecular cloning and characterization of a novel Gossypium barbadense L. RAD-like gene. Plant Mol Biol Rep. 2011;29:324–33.View ArticleGoogle Scholar
  74. Zhang H, Li D, Zhou Z, Zahoor R, Chen B, Meng Y. Soil water and salt affect cotton (Gossypium hirsutum L.) photosynthesis, yield and fiber quality in coastal saline soil. Agric Water Manage. 2017;187:112–21. https://doi.org/10.1016/j.agwat.2017.03.019.View ArticleGoogle Scholar
  75. Abid M, Tian Z, Ataulkarim ST, Wang F, Liu Y. Adaptation to and recovery from drought stress at vegetative stages in wheat (Triticum aestivum) cultivars. Funct Plant Biol. 2016. https://doi.org/10.1071/fp16150.View ArticleGoogle Scholar
  76. Von CS, Lawson T, Oxborough K, Baker NR, Andrews TJ, Raines CA. Stomatal conductance does not correlate with photosynthetic capacity in transgenic tobacco with reduced amounts of Rubisco. J Exp Bot. 2004;55:1157–66. https://doi.org/10.1093/jxb/erh128.View ArticleGoogle Scholar
  77. Xu Z, Zhou G, Shimizu H. Plant responses to drought and rewatering. Plant Signal Behav. 2010;5:649–54. https://doi.org/10.1046/j.1365-3040.2002.00782.x.View ArticlePubMedPubMed CentralGoogle Scholar
  78. Li Y, Zhang L, Wang X, Zhang W, Hao L, Chu X, Guo X. Cotton GhMPK6a negatively regulates osmotic tolerance and bacterial infection in transgenic Nicotiana benthamiana, and plays a pivotal role in development. FEBS J. 2013;280:5128–44. https://doi.org/10.1111/febs.12488.View ArticlePubMedGoogle Scholar
  79. Chastain DR, Snider JL, Choinski JS, Collins GD, Perry CD. Leaf ontogeny strongly influences photosynthetic tolerance to drought and high temperature in Gossypium hirsutum. J Plant Physiol. 2016;199:8–28. https://doi.org/10.1016/j.jplph.2016.05.003.View ArticleGoogle Scholar
  80. Iqbal M, Khan MA, Naeem M, Aziz U, Afzal J, Latif M. Inducing drought tolerance in upland cotton (Gossypium hirsutum L.), accomplishments and future prospects. World Appl Sci J. 2013;21:1062–9. https://doi.org/10.5829/idosi.wasj.2013.21.7.222.View ArticleGoogle Scholar
  81. Wan J, Rebecca G, Ying J, Peter MC, Huang Y. Development of drought-tolerant canola (Brassica napus L.) through genetic modulation of ABA-mediated stomatal responses. Crop Sci. 2009;49:1539–54. https://doi.org/10.2135/cropsci2008.09.0568.View ArticleGoogle Scholar
  82. Ray JD, Sinclair TR. Stomatal closure of maize hybrids in response to drying soil. Crop Sci. 1997;37:803–7. https://doi.org/10.2135/cropsci1997.0011183X003700030018x.View ArticleGoogle Scholar
  83. Bray EA, Bailey-Serres J, Weretilnyk E. Responsestoabiotic stresses. In: Buchanan BB, Gruissem W, Jones RL, editors. Biochemistry and molecular biology of plants. American Society of Plant Physiologists: Rockville; 2002. p. 1158–203.Google Scholar
  84. Pilon C, Oosterhuis DM, Ritchie G, de Paiva Oliveira EA. Effect of drought in the osmotic adjustment of cotton plants. Summaries of Arkansas Cotton Research. 2013; p. 60.Google Scholar
  85. Chen THH, Murata N. Glycinebetaine protects plants against abiotic stress: mechanisms and biotechnological applications. Plant Cell Environ. 2011;34:1–20. https://doi.org/10.1111/j.1365-3040.2010.02232.x.View ArticlePubMedGoogle Scholar
  86. Khan MS, Ahmad D, Khan MA. Utilization of genes encoding osmoprotectants in transgenic plants for enhanced abiotic stress tolerance. Elect J Biotechnol. 2015;18:257–66. https://doi.org/10.1016/j.ejbt.2015.04.002.View ArticleGoogle Scholar
  87. Noreen S, Athar HUR, Ashraf M. Interactive effects of watering regimes and exogenously applied osmoprotectants on earliness indices and leaf area index in cotton (Gossypium hirsutum L.) crop. Pak J Bot. 2013;45:1873–81.Google Scholar
  88. Lv S, Yang A, Zhang K, Wang L, Zhang J. Increase of glycinebetaine synthesis improves drought tolerance in cotton. Mol Breed. 2007;20:233–48. https://doi.org/10.1007/s11032-007-9086-x.View ArticleGoogle Scholar
  89. Divya K, Jami SK, Kirti PB. Constitutive expression of mustard annexin, AnnBj1 enhances abiotic stress tolerance and fiber quality in cotton under stress. Plant Mol Biol. 2010;73:293–308. https://doi.org/10.1007/s11103-010-9615-6.View ArticlePubMedGoogle Scholar
  90. Zhang F, Li S, Yang S, Wang L, Guo W. Overexpression of a cotton annexin gene, GhAnn1, enhances drought and salt stress tolerance in transgenic cotton. Plant Mol Biol. 2015;87:47–67. https://doi.org/10.1007/s11103-014-0260-3.View ArticlePubMedGoogle Scholar
  91. Boudsocq M, Laurière C. Osmotic signaling in plants. Multiple pathways mediated by emerging kinase families. Plant Physiol. 2005;138:1185. https://doi.org/10.1104/pp.105.061275.View ArticlePubMedPubMed CentralGoogle Scholar
  92. Yamaguchishinozaki K, Shinozaki K. Transcriptional regulatory networks in cellular responses and tolerance to dehydration and cold stresses. Annu Rev Plant Biol. 2006;57:781–803. https://doi.org/10.4161/psb.5.6.11398.View ArticleGoogle Scholar
  93. Seo M, Koshiba T. Complex regulation of ABA biosynthesis in plants. Trends Plant Sci. 2002;7:41–8. https://doi.org/10.1016/S1360-1385(01)02187-2.View ArticlePubMedGoogle Scholar
  94. Kuromori T, Koornneef M. ABC transporter AtABCG25 is involved in abscisic acid transport and responses. Proc Natl Acad Sci USA. 2010;107:2361–6. https://doi.org/10.1073/pnas.0912516107.View ArticlePubMedGoogle Scholar
  95. Ma LF, Li Y, Chen Y, Li XB. Improved drought and salt tolerance of Arabidopsis thaliana by ectopic expression of a cotton (Gossypium hirsutum) CBF gene. Plant Cell Tiss Organ Cult. 2016;124:583–98. https://doi.org/10.1007/s11240-015-0917-x.View ArticleGoogle Scholar
  96. Tan J, Tu L, Deng F, Wu R, Zhang X. Exogenous jasmonic acid inhibits cotton fiber elongation. J Plant Growth Regul. 2012;31:599–605. https://doi.org/10.1007/s00344-012-9260-1.View ArticleGoogle Scholar
  97. Bandurska H, Stroiński A, Kubiś J. The effect of jasmonic acid on the accumulation of ABA, proline and spermidine and its influence on membrane injury under water deficit in two barley genotypes. Acta Physiol Plant. 2003;25(3):279–85.View ArticleGoogle Scholar
  98. Riemann M, Dhakarey R, Hazman M, Miro B, Kohli A, Nick P. Exploring jasmonates in the hormonal network of drought and salinity responses. Front Plant Sci. 2015;6:1077. https://doi.org/10.3389/fpls.2015.01077.View ArticlePubMedPubMed CentralGoogle Scholar
  99. Ahmad P, Rasool S, Gul A, Akram NA, Ashraf M, Gucel S. Jasmonates: multifunctional roles in stress tolerance. Front Plant Sci. 2016;7:813. https://doi.org/10.3389/fpls.2016.00813.View ArticlePubMedPubMed CentralGoogle Scholar
  100. Chini A. The JAZ family of repressors is the missing link in jasmonate signalling. Nature. 2007;448:666–71. https://doi.org/10.1371/journal.pone.0143022.View ArticlePubMedGoogle Scholar
  101. Fang Y, Xiong L. General mechanisms of drought response and their application in drought resistance improvement in plants. Cell Mol Life Sci. 2015;72:673–89. https://doi.org/10.1007/s00018-014-1767-0.View ArticlePubMedGoogle Scholar
  102. Gill SS, Tuteja N. Reactive oxygen species and antioxidant machinery in abiotic stress tolerance in crop plants. Plant Physiol Biochem. 2010;48:909–30. https://doi.org/10.1016/j.plaphy.2010.08.016.View ArticlePubMedGoogle Scholar
  103. Carvalho MHCD. Drought stress and reactive oxygen species. Plant Signal Behav. 2008;3:156–65. https://doi.org/10.4161/psb.3.3.5536.View ArticleGoogle Scholar
  104. Heber U. Irrungen, Wirrungen? The Mehler reaction in relation to cyclic electron transport in C3 plants. Photosyn Res. 2002;73:223–31. https://doi.org/10.1023/A:1020459416987.View ArticlePubMedGoogle Scholar
  105. Noctor G, Veljovic-Jovanovic S, Driscoll S, Novitskaya L, Foyer CH. Drought and oxidative load in the leaves of C3 plants: a predominant role for photorespiration? Ann Bot. 2002;89:841–50. https://doi.org/10.1093/aob/mcf096.View ArticlePubMedPubMed CentralGoogle Scholar
  106. Das K, Roychoudhury A. Reactive oxygen species (ROS) and response of antioxidants as ROS-scavengers during environmental stress in plants. Front Environ Sci. 2014;2:53. https://doi.org/10.3389/fenvs.2014.00053.View ArticleGoogle Scholar
  107. Wu S, Hu C, Tan Q, Lu L, Shi K, Zheng Y, Sun X. Drought stress tolerance mediated by zinc-induced antioxidative defense and osmotic adjustment in cotton (Gossypium hirsutum). Acta Physiol Plant. 2015;37:167. https://doi.org/10.1007/s11738-015-1919-3.View ArticleGoogle Scholar
  108. Uzilday B, Turkan I, Sekmen AH, Ozgur R, Karakaya HC. Comparison of ROS formation and antioxidant enzymes in Cleome gynandra (C4) and Cleome spinosa (C4) under drought stress. Plant Sci. 2012;182:59. https://doi.org/10.1016/j.plantsci.2011.03.015.View ArticlePubMedGoogle Scholar
  109. Szalai G, Kellős T, Galiba G, Kocsy G. Glutathione as an antioxidant and regulatory molecule in plants under abiotic stress conditions. J Plant Growth Regul. 2009;28:66–80. https://doi.org/10.1007/s00344-008-9075-2.View ArticleGoogle Scholar
  110. Chan KX, Wirtz M, Phua SY, Estavillo GM, Pogson BJ. Balancing metabolites in drought: the sulfur assimilation conundrum. Trends Plant Sci. 2013;18:18–29. https://doi.org/10.1016/j.tplants.2012.07.005.View ArticlePubMedGoogle Scholar
  111. Zhang X, Wang L, Xu X, Cai C, Guo W. Genome-wide identification of mitogen-activated protein kinase gene family in Gossypium raimondii and the function of their corresponding orthologs in tetraploid cultivated cotton. BMC Plant Biol. 2014;14:345. https://doi.org/10.1186/s12870-014-0345-9.View ArticlePubMedPubMed CentralGoogle Scholar
  112. Ratnayaka HH, Molin WT, Sterling TM. Physiological and antioxidant responses of cotton and spurred anoda under interference and mild drought. J Exp Bot. 2003;54:2293–305. https://doi.org/10.1093/jxb/erg251.View ArticlePubMedGoogle Scholar
  113. Chen T, Li W, Hu X, Guo J, Liu A, Zhang B. A cotton MYB transcription factor, GbMYB5, is positively involved in plant adaptive response to drought stress. Plant Cell Physiol. 2015;56:917–29. https://doi.org/10.1093/pcp/pcv019.View ArticlePubMedGoogle Scholar
  114. Zahoor R, Zhao W, Dong H, Snider JL, Abid M, Zhou Z. Potassium improves photosynthetic tolerance to and recovery from episodic drought stress in functional leaves of cotton (Gossypium hirsutum L.). Plant Physiol Biol. 2017;119:21–32. https://doi.org/10.1016/j.plaphy.2017.08.011.View ArticleGoogle Scholar
  115. Ahmed EM. Hydrogel: preparation, characterization, and applications: a review. J Adv Res. 2015;6:105–21. https://doi.org/10.1016/j.jare.2013.07.006.View ArticlePubMedGoogle Scholar
  116. Dai YN, Li P, Zhang JP, Wang AQ, Wei Q. Swelling characteristics and drug delivery properties of nifedipine-loaded pH sensitive alginate-chitosan hydrogel beads. J Applied Biomaterials. 2010;86:493–500. https://doi.org/10.1002/jbm.b.31046.View ArticleGoogle Scholar
  117. Wu L, Liu M. Preparation and properties of chitosan-coated NPK compound fertilizer with controlled-release and water-retention. J Carbohydrate Polymers. 2008;72:240–7. https://doi.org/10.1016/j.carbpol.2007.08.020.View ArticleGoogle Scholar
  118. Wang M, Zheng Q, Shen Q, Guo S. The critical role of potassium in plant stress response. Int J Mol Sci. 2013;14:7370–90. https://doi.org/10.3390/ijms14047370.View ArticlePubMedPubMed CentralGoogle Scholar
  119. Cakmak I. The role of potassium in alleviating detrimental effects of abiotic stresses in plants. J Plant Nutr Soil Sci. 2005;168:521–30. https://doi.org/10.1002/jpln.200420485.View ArticleGoogle Scholar
  120. Egilla JN, Davies FT, Boutton TW. Drought stress influences leaf water content, photosynthesis, and water-use efficiency of Hibiscus rosa-sinensis at three potassium concentrations. Photosynthetica. 2005;43:135–40. https://doi.org/10.1007/s11099-005-5140-2.View ArticleGoogle Scholar
  121. Anjum SA, Wang C, Farooq M, Hussain M, Xue L. Brassinolide application improves the drought tolerance in maize through modulation of enzymatic antioxidants and leaf gas exchange. J Agron Crop Sci. 2011;197:177–85. https://doi.org/10.1111/j.1439-037X.2010.00459.x.View ArticleGoogle Scholar
  122. Lichtfouse E, Navarrete M, Debaeke P, Souchère V, Alberola C, Ménassieu J. Agronomy for sustainable agriculture. a review. Agron Sustain Dev. 2009;29:1–6. https://doi.org/10.1051/agro:2008054.View ArticleGoogle Scholar
  123. Zheng JY, Oluoch G, Khan R, Wang XX, Cai XY, Zhou ZL, Wang CY, Wang YH, Li XY, Liu F, Wang KB. Mapping QTLs for drought tolerance in an F2:3 population from an inter-specific cross between Gossypium tomentosum and Gossypium hirsutum. Genet Mol Res. 2016;15:15038477. https://doi.org/10.4238/gmr.15038477.View ArticleGoogle Scholar
  124. Lv SL, Zhang JR. Overexpression of Thellungiella halophila H+-PPase (TsVP) in cotton enhances drought stress resistance of plants. Planta. 2008;229:899–910. https://doi.org/10.1007/s00425-008-0880-4.View ArticleGoogle Scholar
  125. Jia YH, Sun JL, Wang XW, Zhou ZL, Pan ZE, He S, Pang B, Wang L, Du X. Molecular diversity and association analysis of drought and salt tolerance in Gossypium hirsutum L. Germplasm J Integr Agric. 2014;13:1845–53. https://doi.org/10.1016/S2095-3119(13)60668-1.View ArticleGoogle Scholar
  126. Ding Y, Ma Y, Liu N, Xu J, Hu Q, Li Y, Wu Y, Xie S, Zhu L, Min L, Zhang XL. MicroRNAs involved in auxin signalling modulate male sterility under high-temperature stress in cotton (Gossypium hirsutum). Plant J. 2017;91:977. https://doi.org/10.1111/tpj.13620.View ArticlePubMedGoogle Scholar
  127. Huang QS, Wang HY, Gao P, Wang GY, Xia GX. Cloning and characterization of a calcium dependent protein kinase gene associated with cotton fiber development. Plant Cell Rep. 2008;27:1869–75. https://doi.org/10.1007/s00299-008-0603-0.View ArticlePubMedGoogle Scholar
  128. Chaves MM, Flexas J, Pinheiro C. Photosynthesis under drought and salt stress: regulation mechanisms from whole plant to cell. Ann Bot. 2009;103:551–60. https://doi.org/10.1093/aob/mcn125.View ArticlePubMedGoogle Scholar
  129. Li L, Yu D, Zhao F, Pang C, Song M, Wei H, Fan S, Yu S. Genome-wide analysis of the calcium-dependent protein kinase gene family in Gossypium raimondii. J Integr Agric. 2015;14:29–41. https://doi.org/10.1016/S2095-3119(14)60780-2.View ArticleGoogle Scholar
  130. Guo M, Liu JH, Ma X, Luo DX, Gong ZH, Lu MH. The plant heat stress transcription factors (HSFs): structure, regulation, and function in response to abiotic stresses. Front Plant Sci. 2016;7:114. https://doi.org/10.3389/fpls.2016.00114.View ArticlePubMedPubMed CentralGoogle Scholar
  131. Xie F, Wang Q, Sun R, Zhang B. Deep sequencing reveals important roles of microRNAs in response to drought and salinity stress in cotton. J Exp Bot. 2015;66:789–804. https://doi.org/10.1093/jxb/eru437.View ArticlePubMedGoogle Scholar
  132. Zhao J, Gao Y, Zhang Z, Chen T, Guo W, Zhang T. A receptor-like kinase gene (GbRLK) from Gossypium barbadense enhances salinity and drought-stress tolerance in Arabidopsis. BMC Plant Biol. 2013;13:110. https://doi.org/10.1186/1471-2229-13-110.View ArticlePubMedPubMed CentralGoogle Scholar
  133. Lu W, Chu X, Li Y, Wang C, Guo X. Cotton GhMKK1 induces the tolerance of salt and drought stress, and mediates defence responses to pathogen infection in transgenic Nicotiana benthamiana. PLoS ONE. 2013;8:e68503. https://doi.org/10.1371/journal.pone.0068503.View ArticlePubMedPubMed CentralGoogle Scholar
  134. Dong T, Park Y, Hwang I. Abscisic acid: biosynthesis, inactivation, homoeostasis and signalling. Essays Biochem. 2015;58:29–48. https://doi.org/10.1042/bse0580029.View ArticlePubMedGoogle Scholar
  135. He L, Yang X, Wang L, Zhu L, Zhou T, Deng J, Zhang X. Molecular cloning and functional characterize abiotic stress tolerance in transgenic plants. Biochem Biophys Res Commun. 2013;435:209–15. https://doi.org/10.1016/j.bbrc.2013.04.080.View ArticlePubMedGoogle Scholar
  136. Zhang H, Shen G, Kuppu S, Gaxiola R, Payton P. Creating drought- and salt-tolerant cotton by overexpressing a vacuolar pyrophosphatase gene. Plant Signal Behav. 2011;6:861–3. https://doi.org/10.4161/psb.6.6.15223.View ArticlePubMedPubMed CentralGoogle Scholar
  137. Hozain MD, Abdelmageed H, Lee J, Kang M, Fokar M, Allen RD, Holaday AS. Expression of AtSAP5 in cotton up-regulates putative stress-responsive genes and improves the tolerance to rapidly developing water deficit and moderate heat stress. J Plant Physiol. 2012;169:1261–70. https://doi.org/10.1016/j.jplph.2012.04.007.View ArticlePubMedGoogle Scholar
  138. Zhou B, Zhang L, Ullah A, Jin X, Yang X, Zhang X. Identification of multiple stress responsive genes by sequencing a normalized cDNA library from sea-land cotton (Gossypium barbadense L.). PLoS ONE. 2016;11:e0152927. https://doi.org/10.1371/journal.pone.0152927.View ArticlePubMedPubMed CentralGoogle Scholar
  139. Herd RW. Biotechnology in agriculture. Annu Rev Environ Resour. 2006;31:265–95. https://doi.org/10.1146/annurev.energy.31.031405.091314.View ArticleGoogle Scholar
  140. Levi A, Ovnat L, Paterson AH, Saranga Y. Photosynthesis of cotton near-isogenic lines introgressed with QTLs for productivity and drought related traits. Mol Breed. 2009;23:179–95. https://doi.org/10.1016/j.plantsci.2009.04.001.View ArticleGoogle Scholar
  141. Yang H, Zhang D, Li X, Li H, Zhang D, Lan H, Wood AJ, Wang L. Overexpression of ScALDH21 gene in cotton improves drought tolerance and growth in greenhouse and field conditions. Mol Breed. 2016;36:1–13. https://doi.org/10.1007/s11032-015-0422-2.View ArticleGoogle Scholar
  142. Mehrotra R, Bhalothia P, Bansal P, Basantani MK, Bharti V, Mehrotraa S. Abscisic acid and abiotic stress tolerance-different tiers of regulation. J Plant Physiol. 2014;171:486–96. https://doi.org/10.1016/j.jplph.2013.12.007.View ArticlePubMedGoogle Scholar
  143. Zhang Y, Zhang F, Li X, Baller JA, Qi Y, Starker CG, Bogdanove AJ, Voytas DF. Transcription activator-like effector nucleases enable efficient plant genome engineering. Plant Physiol. 2013;161:20–7. https://doi.org/10.1104/pp.112.205179.View ArticlePubMedGoogle Scholar
  144. Yu LH, Wu SJ, Peng YS, Liu RN, Chen X, Zhao P, Xu P, Zhu JB, Jiao GL, Pei Y, Xiang CB. Arabidopsis EDT1/HDG11 improves drought and salt tolerance in cotton and poplar and increases cotton yield in the field. Plant Biotechnol J. 2015;14:72–84. https://doi.org/10.1111/pbi.12358.View ArticlePubMedGoogle Scholar
  145. Liu G, Li X, Jin S, Liu X, Zhu L, Nie Y, Zhang X. Overexpression of rice NAC gene SNAC1 improves drought and salt tolerance by enhancing root development and reducing transpiration rate in transgenic cotton. PLoS ONE. 2014;9:e86895. https://doi.org/10.1111/mpp.12067.View ArticlePubMedPubMed CentralGoogle Scholar
  146. Popescu SC, Popescu GV, Bachan S, Zhang Z, Gerstein M, Snyder M, Dinesh-Kumar SP. MAPK target networks in Arabidopsis thaliana revealed using functional protein microarrays. Genes Dev. 2009;23:80–92. https://doi.org/10.1101/gad.1740009.View ArticlePubMedPubMed CentralGoogle Scholar
  147. Parkhi V, Kumar V, Sunilkumar G, LaM Campbell, Singh NK, Rathore KS. Expression of apoplastically secreted tobacco osmotin in cotton confers drought tolerance. Mol Breed. 2009;23:625–39. https://doi.org/10.1007/s11032-009-9261-3.View ArticleGoogle Scholar
  148. Levi A, Paterson AH, Cakmak I, Saranga Y. Metabolite and mineral analyses of cotton near-isogenic lines introgressed with QTLs for productivity and drought-related traits. Physiol Plant. 2011;141:265–75. https://doi.org/10.1111/j.1399-3054.2010.01438.x.View ArticlePubMedGoogle Scholar
  149. Yan H, Jia H, Chen X, Hao L, An H, Guo X. The cotton WRKY transcription factor GhWRKY17 functions in drought and salt stress in transgenic nicotiana benthamiana through ABA signalling and the modulation of reactive oxygen species production. Plant Cell Physiol. 2014;55:2060–76. https://doi.org/10.1093/pcp/pcu133.View ArticlePubMedGoogle Scholar
  150. Zhang J, Zou D, Li Y, Sun X, Wang NN, Guo SY, Zheng Y, Bao L. GhMPK17, a cotton mitogen-activated protein kinase, is involved in plant response to high salinity and osmotic stresses and ABA signaling. PLoS ONE. 2014;9:e95642. https://doi.org/10.1371/journal.pone.0095642.View ArticlePubMedPubMed CentralGoogle Scholar
  151. Petolino JF. Genome editing in plants via designed zinc finger nucleases. Vitro Cell Dev Biol Plant. 2015;51:1–8.View ArticleGoogle Scholar
  152. Wang F, Wang C, Liu P, Lei C, Hao W, Guo Y, Liu Y, Zhao K. Enhanced rice blast resistance by CRISPR/Cas9-targeted mutagenesis of the ERF transcription factor gene OsERF922. PLoS ONE. 2016;11:e0154027. https://doi.org/10.1371/journal.pone.0154027.View ArticlePubMedPubMed CentralGoogle Scholar
  153. Feng Z, Mao Y, Xu N, Zhang B, Wei P, Yang DL, Wang Z, Zhang Z, Zheng R, Yang L, Zeng L, Liu X, Zhu J. Multigeneration analysis reveals the inheritance, specificity, and patterns of CRISPR/Cas-induced gene modifications in Arabidopsis. Proc Natl Acad Sci USA. 2014;111:4632. https://doi.org/10.1073/pnas.1400822111.View ArticlePubMedGoogle Scholar
  154. Zhou X, Zha M, Huang J, Li L, Imran M, Zhang C. StMYB44 negatively regulates phosphate transport by suppressing expression ofPHOSPHATE1 in potato. J Exp Bot. 2017;68:1265–81. https://doi.org/10.1093/jxb/erx026.View ArticlePubMedPubMed CentralGoogle Scholar
  155. Tian S, Jiang L, Gao Q, Zhang J, Zong M, Zhang H, Ren L, Guo S, Gong G, Liu F, Xu Y. Efficient CRISPR/Cas9-based gene knockout in watermelon. Plant Cell Rep. 2017;36:399–406. https://doi.org/10.1007/s00299-016-2089-5.View ArticlePubMedGoogle Scholar
  156. Liang Z, Zhang K, Chen K, Gao C. Targeted mutagenesis in zea mays using TALENs and the CRISPR/Cas system. J Genetics Genomics. 2014;41:63–8. https://doi.org/10.1016/j.jgg.2013.12.001.View ArticleGoogle Scholar
  157. Ito Y, Nishizawayokoi A, Endo M, Mikami M, Toki S. CRISPR/Cas9-mediated mutagenesis of the RIN locus that regulates tomato fruit ripening. Biochem Biophys Res Commun. 2015;467:76–82. https://doi.org/10.1016/j.bbrc.2015.09.117.View ArticlePubMedGoogle Scholar
  158. Jacobs TB, Lafayette PR, Schmitz RJ, Parrott WA. Targeted genome modifications in soybean with CRISPR/Cas9. BMC Biotechol. 2015;15:1–10. https://doi.org/10.1186/s12896-015-0131-2.View ArticleGoogle Scholar
  159. Jinek M, Chylinski K, Fonfara I, Hauer M, Doudna JA, Charpentier E. A programmable dual-RNA–guided DNA endonuclease in adaptive bacterial immunity. Science. 2012;337:816–21.View ArticleGoogle Scholar
  160. Lowder LG, Zhang D, Baltes NJ, Paul JW, Tang X, Zheng X, Voytas DF, Hsieh TF, Zhang Y, Qi Y. A CRISPR/Cas9 toolbox for multiplexed plant genome editing and transcriptional regulation. Plant Physiol. 2015;169:971–85.View ArticleGoogle Scholar
  161. Mei Y, Wang Y, Chen H, Sun ZS, Ju XD. Recent progress in CRISPR/Cas9 technology. J Genet Genomics. 2016;43:63–75.View ArticleGoogle Scholar
  162. Wang M, Tu L, Lin M, Lin Z, Wang P, Yang Q, Ye Z, Shen C, Li J, Zhang L, Zhou X, Nie X, Li Z, Guo K, Ma Y, Huang C, Jin S, Zhu L, Yang X, Min L, Yuan D, Zhang Q, Lindsey K, Zhang X. Asymmetric subgenome selection and cis-regulatory divergence during cotton domestication. Nat Genet. 2017;49:579–87.View ArticleGoogle Scholar
  163. Doudna JA, Charpentier E. Genome editing. The new frontier of genome engineering with CRISPR–Cas9. Science. 2014;346:1258096. https://doi.org/10.1126/science.1258096.View ArticlePubMedGoogle Scholar
  164. Ma X, Zhang Q, Zhu Q, Liu W, Chen Y. A robust CRISPR/Cas9 system for convenient, high-efficiency multiplex genome editing in monocot and dicot plants. Mol Plant. 2015;8:1274–84. https://doi.org/10.1016/j.molp.2015.04.007.View ArticlePubMedGoogle Scholar
  165. Curtin SJ, Zhang F, Sander JD, Haun WJ, Starker C, Baltes N, Reyon D, Dahlborg E, Goodwin MJ, Coffman AP, Dobbs D, Joung JK, Voytas DF, Stupar RM. Targeted mutagenesis of duplicated genes in soybean with zinc-finger nucleases. Plant Physiol. 2011;156:466–73. https://doi.org/10.1104/pp.111.172981.View ArticlePubMedPubMed CentralGoogle Scholar
  166. Zhang L, Li Y, Lu W, Meng F, Wu CA, Guo X. Cotton GhMKK5 affects disease resistance, induces HR-like cell death, and reduces the tolerance to salt and drought stress in transgenic Nicotiana benthamiana. J Exp Bot. 2012;63:3935. https://doi.org/10.1093/jxb/ers086.View ArticlePubMedPubMed CentralGoogle Scholar
  167. Li DX, Li CD, Sun HC, Liu LT, Zhang YJ. Photosynthetic and chlorophyll fluorescence regulation of upland cotton (Gossiypium hirsutum L.) under drought conditions. Plant Omics J. 2012;5:432–7.Google Scholar

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