Unveiling the role of heat shock protein 83 (HSP83) in Gossypium hirsutum in enhancing whitefly stress tolerance.

Heat shock proteins (HSPs) are key molecular chaperones that control protein homeostasis and stress signalling in plants. They have been widely studied for abiotic stresses, such as drought and heat; however, their role in insect-mediated biotic stress is little known, especially in polyploid crops like cotton, which is an important economic crop. Whitefly, Bemisia tabaci (Gennadius), infestation is a serious agronomic constraint in cotton (Gossypium spp.); however, efforts to completely investigate the genetic and molecular components driving host resistance against this pest have not been entirely successful yet. In this study, a genome-wide analysis of heat shock proteins (HSPs) families in cotton varieties has been conducted to investigate the involvement of HSPs in whitefly stress. About 505 HSPs genes are found unequally distributed in the genomes of four cotton species. Chromosomal locations and their mapping have shown the highest number of genes at chromosome 9 in G. hirsutum and G. barbadense; at chromosome 6 in G. raimondii; and at chromosome 5 in G. arboreum. Gene ontology, evolutionary dynamics and domain analysis have been performed for HSP families in cotton, which showed the presence of different conserved domains important for biological as well as molecular functions. The HSP83, belonging to the HSP90 gene family, has been focused on in cotton species for this particular aspect due to the differential expression suggested by reference RNA-sequencing data. The gene structure of these HSP83s is similar, and all contain a conserved HSP90 superfamily coding for important domains like HSP90-like ATPase. In addition, various important cis-regulatory elements like bZIP, WRKY, and GT1-motif, related to different signalling and stress patterns during the central dogma, have been found in the promoter regions of HSP83s. The functional validation was done by virus-induced gene silencing (VIGS) of the target HSP83 gene found at chromosome 12 in G. hirsutum which showed increased whitefly infestation in the infiltrated plants. These results demonstrate that HSP83 is a conserved molecular regulator of cotton's resistance to whiteflies and that it aids in maintaining stress-responsive signalling networks when insects attack. HSP83's evolutionary conservation, promoter architecture, and functional validation all point to it being an important component of polyploid cotton's defensive mechanism. These results provide a molecular foundation for integrating chaperone-mediated stress regulation into crop development initiatives and further our knowledge of HSP90-family proteins in plant-insect interactions.