Genome-Wide Profiling of WRKY, HSC, and ProDh Gene Families and VIGS-Mediated Functional Analysis of Negative Regulators of Cotton's Stress Response to Drought, Heat, and Whiteflies

Biotic and abiotic stress are fundamental contributors to restricting cotton yield and performance. Comprehension of molecular mechanisms behind these responses is necessary for elevating stress resistance. Genome wide profiling classified 100 WRKY, 63 HSC, and 10 ProDh family proteins identified in Gossypium hirsutum based on conserved domains and motif, and phylogenetic analysis. In the present study HSC70-1 , WRKY27 , and ProDh were characterized as negative stress regulators of heat, drought, and whiteflies and their functional analyses were performed to validate the roles of these genes in modulating the intensity of stress response and defense mechanism via Virus-Induced Gene Silencing (VIGS) using foliar sprays – a novel approach for transient gene silencing in cotton. Downregulation of HSC70-1 resulted in strong resilience to drought and heat stress. WRKY27 was the strong negative modulator of whiteflies and heat, and ProDh silenced plants showed susceptibility to all stresses. The relative expression of some other genes, BBX18 , GASA5 , MAP3K65 , and CKX1 , involved in these stress related pathways was also quantified. BBX18 and GASA5 were found downregulated in all silenced plants whereas MAP3K65 showed upregulation in HSC70 - 1 silenced plants while CKX1 was upregulated in WRKY27 silenced plants. Overall, this study aims to provide the functional importance of down-regulators to make heat, drought, and whitefly tolerant plants.