Morphophysiological and molecular effects of drought stress in rice

Drought is a major abiotic stress that adversely affects the rice growth, mostly in the rainfed ecosystem that ultimately affects the biomass production and yield. Rice needs to adapt a series of physiological mechanisms with complicated regulatory network to fight and cope up with the unfavourable conditions due to drought stress. Morphological and physiological response in rice include inhibition of seed germination, slower growth rate, low root and shoot length, lower chlorophyll content, stomatal closure, lower rate of photosynthesis, yield reduction etc. Stress condition further results in development of response at the molecular level by the generation of reactive oxygen species (ROS) such as O2*-, H2O2, 1O2, OH* etc. which incites oxidative stress in the plants. Oxidative stress is overcome by the inherent capacity of plants to produce antioxidant species which may be enzymatic or non-enzymatic in nature. If however antioxidant defence mechanism cannot overpower the ROS generated, they cause oxidative damage to the plant tissues such as lipid peroxidation, protein oxidation, DNA damage, etc. resulting in cell death. Unlike other stresses, drought affects the physiology and biochemistry of the rice which adversely affects in the morphology and consequently delimits the yield of the plant. Therefore, understanding the morphological, biochemical and molecular mechanisms involved in rice against drought is utmost necessary for rice breeders to improve the rice for drought tolerant/resistance varieties for future green revolution. In this review, an attempt has been made to highlight the complex regulatory network involved in rice against drought with special emphasis on morphological, physiological and molecular mechanisms and to discuss the prospective and challenges for future plant breeders.

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Penconazole and calcium ameliorate drought stress in canola by upregulating the antioxidative enzymes

Functional Plant Biology ◽

10.1071/fp19341 ◽

2020 ◽

Vol 47 (9) ◽

pp. 825 ◽

Cited By ~ 1

Author(s):

Maryam Rezayian ◽

Vahid Niknam ◽

Hassan Ebrahimzadeh

Keyword(s):

Oxidative Stress ◽

Lipid Peroxidation ◽

Drought Stress ◽

Drought Tolerance ◽

Antioxidative Enzymes ◽

Proline Content ◽

Fresh Weight ◽

Negative Effects ◽

Mda Content ◽

Effects Of Drought

The aim of this research was to gauge the alternations in the lipid peroxidation and antioxidative enzyme activity in two cultivars (cv. RGS003 and cv. Sarigol) of canola under drought stress and drought tolerance amelioration by penconazole (PEN) and calcium (Ca). Plants were treated with different polyethylene glycol (PEG) concentrations (0, 5, 10 and 15%) without or with PEN (15 mg L–1) and Ca (15 mM). The Ca treatment prevented the negative effects of drought on fresh weight (FW) in RGS003 and Sarigol at 5 and 15% PEG respectively. Ca and PEN/Ca treatments caused significant induction in the proline content in Sarigol at 15% PEG; the latter treatment was accompanied by higher glycine betaine (GB), lower malondialdehyde (MDA) and growth recovery. Hydrogen peroxide (HO2) content in Sarigol was proportional to the severity of drought stress and all PEN, Ca and PEN/Ca treatments significantly reduced the H2O2 content. PEN and PEN/Ca caused alleviation of the drought-induced oxidative stress in RGS003. RGS003 cultivar exhibited significantly higher antioxidative enzymes activity at most levels of drought, which could lead to its drought tolerance and lower MDA content. In contrast to that of Sarigol, the activity of catalase and superoxide dismutase (SOD) increased with Ca and PEN/Ca treatments in RGS003 under low stress. The application of PEN and Ca induced significantly P5CS and SOD expression in RGS003 under drought stress after 24 h. Overall, these data demonstrated that PEN and Ca have the ability to enhance the tolerance against the drought stress in canola plants.

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Arabidopsis MADS-box factor AGL16 negatively regulates drought resistance via stomatal density and stomatal movement

Journal of Experimental Botany ◽

10.1093/jxb/eraa303 ◽

2020 ◽

Vol 71 (19) ◽

pp. 6092-6106 ◽

Cited By ~ 3

Author(s):

Ping-Xia Zhao ◽

Zi-Qing Miao ◽

Jing Zhang ◽

Si-Yan Chen ◽

Qian-Qian Liu ◽

...

Keyword(s):

Drought Stress ◽

Drought Resistance ◽

Molecular Mechanisms ◽

Stomatal Density ◽

Stomatal Closure ◽

Negative Regulator ◽

Stomatal Development ◽

Mads Box ◽

Mobility Shift ◽

Aba Metabolism

Abstract Drought is one of the most important environmental factors limiting plant growth and productivity. The molecular mechanisms underlying plant drought resistance are complex and not yet fully understood. Here, we show that the Arabidopsis MADS-box transcription factor AGL16 acts as a negative regulator in drought resistance by regulating stomatal density and movement. Loss-of-AGL16 mutants were more resistant to drought stress and had higher relative water content, which was attributed to lower leaf stomatal density and more sensitive stomatal closure due to higher leaf ABA levels compared with the wild type. AGL16-overexpressing lines displayed the opposite phenotypes. AGL16 is preferentially expressed in guard cells and down-regulated in response to drought stress. The expression of CYP707A3 and AAO3 in ABA metabolism and SDD1 in stomatal development was altered in agl16 and overexpression lines, making them potential targets of AGL16. Using chromatin immunoprecipitation, transient transactivation, yeast one-hybrid, and electrophoretic mobility shift assays, we demonstrated that AGL16 was able to bind the CArG motifs in the promoters of the CYP707A3, AAO3, and SDD1 and regulate their transcription, leading to altered leaf stomatal density and ABA levels. Taking our findings together, AGL16 acts as a negative regulator of drought resistance by modulating leaf stomatal density and ABA accumulation.

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MADS-box factor AGL16 negatively regulates drought resistance via stomatal density and stomatal movement

10.1101/723106 ◽

2019 ◽

Author(s):

Ping-Xia Zhao ◽

Zi-Qing Miao ◽

Jing Zhang ◽

Qian-Qian Liu ◽

Cheng-Bin Xiang

Keyword(s):

Drought Stress ◽

Drought Resistance ◽

Molecular Mechanisms ◽

Stomatal Density ◽

Stomatal Closure ◽

Negative Regulator ◽

Stomatal Development ◽

Mads Box ◽

Loss Of Function ◽

Research Attention

ABSTRACTDrought is one of the most severe environmental factors limiting plant growth and productivity. Plants respond to drought by closing stomata to reduce water loss. The molecular mechanisms underlying plant drought resistance are very complex and yet to be fully understood. While much research attention has been focused on the positive regulation of stomatal closure, less is known about its negative regulation, equally important in this reversible process. Here we show that the MADS-box transcriptional factor AGL16 acts as a negative regulator in drought resistance by regulating both stomatal density and movement. Loss-of-function mutantagl16was more resistant to drought stress with higher relative water content, which was attributed to a reduced leaf stomatal density and more sensitive stomatal closure due to a higher leaf ABA level compared with wild type, whileAGL16overexpression lines displayed the opposite phenotypes.AGL16is preferentially expressed in guard cells and down regulated in response to drought stress. The expression ofCYP707A3andAAO3in ABA metabolism andSDD1in stomatal development was altered by AGL16 as shown inagl16and overexpression lines. Chromatin immunoprecipitation, transient transactivation, and yeast-one-hybrid assays demonstrated that AGL16 bound the CArG motif in the promoter of theCYP707A3,AAO3, andSDD1to regulate their transcription, and therefore alter leaf stomatal density and ABA level. Taken together, AGL16 acts as a negative regulator of drought resistance by modulating leaf stomatal density and ABA accumulation.

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Nanomaterials. Effective tools for field and horticultural crops to cope with drought stress: A review

Spanish Journal of Agricultural Research ◽

10.5424/sjar/2020182-16181 ◽

2020 ◽

Vol 18 (2) ◽

pp. e08R01

Author(s):

Hanafey F. Maswada ◽

Yasser S. A. Mazrou ◽

Abdelnaser A. Elzaawely ◽

Shamel M. Alam-Eldein

Keyword(s):

Oxidative Stress ◽

Drought Stress ◽

Water Status ◽

Stomatal Closure ◽

Regulation Of Gene Expression ◽

Crop Plants ◽

Stress Factors ◽

Enzymatic Antioxidants ◽

Growth Physiology ◽

Stress Damage

Drought is the most serious environmental challenge that limits plant growth and causes more severe yield losses than other abiotic stress factors resulting in a serious food shortage. Nanomaterials (NMs) are considered as vital tools to overcome contemporary and future challenges in agricultural production. Recently, NMs have been applied for enhancing seed germination, growth, physiology, productivity and quality attributes of various crops under normal or stress conditions. Up to date, there is no comprehensive review about the potential role of NMs in attenuating the drought-induced adverse effects in crop plants. Thus, this review will highlight this issue. Generally, NMs minimize drought-induced osmotic stress by accumulation of osmolytes that result in osmotic adjustment and improved plant water status. In addition, NMs play a key role to improve root growth, conductive tissue elements and aquaporin proteins facilitating uptake and translocation of water and nutrients. Furthermore, NMs reduce water loss by stomatal closure due to abscisic acid signaling. However, this leads to reduced photosynthesis and oxidative stress damage. At the same time, NMs increase the content of light-harvesting pigments, enzymatic and non-enzymatic antioxidants leading to enhancing photosynthesis with reducing oxidative stress damage. Overall, NMs can ameliorate the deleterious effects of drought stress in crop plants by regulation of gene expression and alternation of various physiological and biochemical processes.

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Drought Stresses on Seed Germination and Early Growth of Maize and Sorghum

Journal of Agricultural Science ◽

10.5539/jas.v11n2p310 ◽

2019 ◽

Vol 11 (2) ◽

pp. 310 ◽

Cited By ~ 3

Author(s):

Mariana S. Queiroz ◽

Carlos E. S. Oliveira ◽

Fábio Steiner ◽

Alan M. Zuffo ◽

Tiago Zoz ◽

...

Keyword(s):

Drought Stress ◽

Seed Germination ◽

Osmotic Potential ◽

Germination Rate ◽

Early Growth ◽

Root Shoot Ratio ◽

Randomized Design ◽

Root And Shoot Length ◽

Early Seedling ◽

Effects Of Drought

Seeds of maize (Zea mays L.) and sorghum [Sorghum bicolor (L.) Moench.] were submitted to different osmotic potential levels induced by polyethylene glycol (PEG) with the objective of evaluating the effects of drought stress on seed germination and early seedling growth. Seeds were arranged in paper rolls and soaked in PEG solutions prepared with osmotic potentials 0.0 (control), -0.2, -0.4, and -0.8 MPa and kept into a seed germinator, at 25 °C for 18 days. A completely randomized design in a 2 × 4 factorial scheme with four replications of 50 seeds each was used. The results showed that by increasing of the osmotic potential level, germinated seed number, germination rate index, root and shoot length, shoot and root dry matter, and seedling vigor index (SVI) decreased, while mean germination time (MGT) and root: shoot ratio (RSR) increased in both crops. Additionally, the maize was more susceptible than sorghum to drought stress, with germination response declining more rapidly with decreasing osmotic potential. Sorghum crop tolerates water stress of up to -0.2 MPa, without reducing germination of the seeds; however, the growth of shoots and roots are inhibited. Drought stress limits the process of seed germination and early growth of maize seedlings.

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Melatonin Mediated Regulation of Drought Stress: Physiological and Molecular Aspects

Plants ◽

10.3390/plants8070190 ◽

2019 ◽

Vol 8 (7) ◽

pp. 190 ◽

Cited By ~ 28

Author(s):

Sharma ◽

Zheng

Keyword(s):

Oxidative Stress ◽

Drought Stress ◽

Photosynthetic Apparatus ◽

Severe Drought ◽

Defense System ◽

Ros Scavenging ◽

Effects Of Drought ◽

Molecular Aspects ◽

Underlying Mechanisms ◽

Scavenging Efficiency

Drought stress adversely effects physiological and biochemical processes of plants, leading to a reduction in plant productivity. Plants try to protect themselves via activation of their internal defense system, but severe drought causes dysfunction of this defense system. The imbalance between generation and scavenging of reactive oxygen species (ROS) leads to oxidative stress. Melatonin, a multifunctional molecule, has the potential to protect plants from the adverse effects of drought stress by enhancing the ROS scavenging efficiency. It helps in protection of photosynthetic apparatus and reduction of drought induced oxidative stress. Melatonin regulates plant processes at a molecular level, which results in providing better resistance against drought stress. In this review, the authors have discussed various physiological and molecular aspects regulated by melatonin in plants under drought conditions, along with their underlying mechanisms.

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ABF3 enhances drought tolerance via promoting ABA-induced stomatal closure by directly regulating ADF5 in Populus euphratica

Journal of Experimental Botany ◽

10.1093/jxb/eraa383 ◽

2020 ◽

Vol 71 (22) ◽

pp. 7270-7285 ◽

Cited By ~ 1

Author(s):

Yanli Yang ◽

Hui-Guang Li ◽

Jie Wang ◽

Hou-Ling Wang ◽

Fang He ◽

...

Keyword(s):

Drought Stress ◽

Drought Tolerance ◽

Molecular Mechanisms ◽

Stomatal Closure ◽

Membrane Integrity ◽

Populus Euphratica ◽

Populus Tomentosa ◽

Limiting Factor ◽

Mobility Shift ◽

Cell Membrane Integrity

Abstract Water availability is a main limiting factor for plant growth, development, and distribution throughout the world. Stomatal movement mediated by abscisic acid (ABA) is particularly important for drought adaptation, but the molecular mechanisms in trees are largely unclear. Here, we isolated an ABA-responsive element binding factor, PeABF3, in Populus euphratica. PeABF3 was preferentially expressed in the xylem and young leaves, and was induced by dehydration and ABA treatments. PeABF3 showed transactivation activity and was located in the nucleus. To study its functional mechanism in poplar responsive to drought stress, transgenic triploid white poplars (Populus tomentosa ‘YiXianCiZhu B385’) overexpressing PeABF3 were generated. PeABF3 overexpression significantly enhanced stomatal sensitivity to exogenous ABA. When subjected to drought stress, PeABF3 overexpression maintained higher photosynthetic activity and promoted cell membrane integrity, resulting in increased water-use efficiency and enhanced drought tolerance compared with wild-type controls. Moreover, a yeast one-hybrid assay and an electrophoretic mobility shift assay revealed that PeABF3 activated the expression of Actin-Depolymerizing Factor-5 (PeADF5) by directly binding to its promoter, promoting actin cytoskeleton remodeling and stomatal closure in poplar under drought stress. Taken together, our results indicate that PeABF3 enhances drought tolerance via promoting ABA-induced stomatal closure by directly regulating PeADF5 expression.

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