Sarwar MKS, Usman M, Asif F, Kalsoom R, Tabbusam S and Zeeshan M, 2024. Effect of drought stress and response in cotton. Trends in Animal and Plant Sciences 4: 61-73. https://doi.org/10.62324/TAPS/2024.048

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Gossypium hirsutum is one of the most vital economical crops. With climatic changes and global warming, its production is seriously affected and decreased. Among these climatic stresses, drought is the leading abiotic stress that lessens its yields. It affects negatively (directly or indirectly) on several processes including morphological, physiological, anatomical and biochemical processes in cotton plants that leads to down regulation of cotton plant’s growth. Under drought stress, cotton plants reduce water loss through rolling of leaf margins, which decreases the surface area exposed to radiation. This response greatly inhibits the rate of photosynthesis, mostly because of reduced stomata conductance. The diminished photosynthetic activity results in a decline in dry matter, suggesting that flowers are somewhat protected from water scarcity compared to neighboring leaves. Various stress-responsive genes also participate in this process and aid the cotton plant in its ability to endure unfavorable conditions. In addition, drought stress decreases the expression of GhSUT-1, a sucrose transporter that is essential for exporting photosynthetic carbon assimilates. Drought stress affects important enzymes involved in starch production, including AGPase, GBSSase, and SSSase. During drought conditions, the activity of GBSSase, which is responsible for the synthesis of amylose, increases. However, the activity of AGPase, which is involved in the development of both amylose and amylopectin, is greatly reduced, thereby impeding the production of both starch components. In addition, a reduction in SSSase activity leads to a decrease in the generation of starch and a decrease in the amount of energy produced by the oxidation of glucose in cellular respiration.