Unravelling the Functional Role of GthGAPC2 in Cotton's Defense Against Verticillium dahliae through Proteome

Abstract Cotton (Gossypium spp.) is an economically important crop, but its productivity is often hindered by the soil‐borne pathogen Verticillium dahliae . This study aimed to investigate the response of cotton roots to V. dahliae infection by analysing the proteome of Gossypium thurberi (resistant) and Gossypium raimondii (susceptible) at 0 h, 24 h, and 48 h post‐infection. Through weighted protein coexpression network analysis, fifteen hub proteins crucial for defense against V. dahliae were identified. Expression analysis revealed the pivotal role of GthGAPC2 , encoding GLYCERALDEHYDE‐3‐PHOSPHATE DEHYDROGENASE 2, in conferring resistance to V. dahliae in cotton. Virus‐induced gene Silencing (VIGS) of GthGAPC2 increased susceptibility to V. dahliae , which was supported by oxidant and antioxidant enzyme activities. Furthermore, GthGAPC2 silencing influenced lignin content, indicating its involvement in lignin biosynthesis regulation. Transient overexpression of GthGAPC2 in tobacco supported its role in cell death processes. Subcellular localization studies showed predominant nuclear localization of GthGAPC2 . Overexpression of GthGAPC2 in Arabidopsis also confirms its significant role in V. dahliae resistance. These findings shed light on the molecular mechanisms of disease resistance in Gossypium thurberi . Identification of GthGAPC2, as a key protein involved in V. dahliae resistance, and its functional implications can aid breeding strategies for enhancing cotton's disease resistance.