COTTON BIOTECHNOLOGY FOR DROUGHT STRESS: AN OVERVIEW OF CHALLENGES AND STRATEGIES FOR SUSTAINABLE COTTON PRODUCTION

In Pakistan, cotton is a significant cash and fibre crop. Water stress inhibits the development and growth of plants by modifying biological processes and metabolic activity. Since the severity and length of the stress are crucial for plant growth, losses due to water constraints in crop yield outweigh losses due to all other factors combined. Water-deficit stress significantly decreases crop production by affecting morpho-physiological characteristics which ultimately decreases the fibre quality and reduces the seed cotton yield. Tolerating water deficits includes two crucial stages involving the upregulation of signalling pathways and stimulating molecular expression responses. Enhancement requires various stress-related actions of plants, particularly mechanisms at the physiological, molecular and biochemical regions. The physiological functions indicators of water stress, including stomata closure as well as the development of roots, cellular adaptations, pollen tube maturation, osmotic adjustments, photosynthesis, abscisic acid (ABA), Jasmonic acid (JA) and other phytohormones are generated, along with reactivity of oxygen species (ROS). Stress conditions influence the molecular basis, quantitative trait loci (QTL) and genes related to moisture-deficit tolerance in cotton. Several genetic strategies for genome alteration such as genetic engineering, manipulation of microRNAs, functional genomics and the CRISPR/Cas9 system assist in the growth of cotton tolerance. Different genetic approaches can make it easier to find superior candidate genes connected to stress physiology approaches to functional genomics. We propose the use of comparative analyses of third-generation sequencing data (transcriptomics, proteomics and epigenomic) along with genome-wide analysis and functional genomic techniques to determine and differentiate novel genes. This review will help to comprehend the intricate molecular biology of stress in plants. As the intensity and length of the stress are censorious for plant growth, losses due to water constraints in crop yield outweigh losses due to all other factors combined.