GhENODL6 Isoforms from the Phytocyanin Gene Family Regulated Verticillium Wilt Resistance in Cotton

Verticillium wilt (VW), a fungal disease caused byVerticillium dahliae, currently devastates cotton fiber yield and quality seriously, yet few resistance germplasm resources have been discovered inGossypium hirsutum. The cotton variety Nongda601 with suitable VW resistance and high yield was developed in our lab, which supplied elite resources for discovering resistant genes. Early nodulin-like protein (ENODL) is mainly related to nodule formation, and its role in regulating defense response has been seldom studied. Here, 41 conserved ENODLs inG. hirsutumwere identified and characterized, which could divide into four subgroups. We found thatGhENODL6was upregulated underV. dahliaestress and hormonal signal and displayed higher transcript levels in resistant cottons than the susceptible. TheGhENODL6was proved to positively regulate VW resistance via overexpression and gene silencing experiments. Overexpression ofGhENODL6significantly enhanced the expressions of salicylic acid (SA) hormone-related transcription factors and pathogenicity-related (PR) protein genes, as well as hydrogen peroxide (H2O2) and SA contents, resulting in improved VW resistance in transgenicArabidopsis. Correspondingly, in theGhENODL6silenced cotton, the expression levels of both phenylalanine ammonia lyase (PAL) and 4-coumarate-CoA ligase (4CL) genes significantly decreased, leading to the reduced SA content mediating by the phenylalanine ammonia lyase pathway. Taken together,GhENODL6played a crucial role in VW resistance by inducing SA signaling pathway and regulating the production of reactive oxygen species (ROS). These findings broaden our understanding of the biological roles ofGhENODLand the molecular mechanisms underlying cotton disease resistance.Keywords:Gossypium hirsutum;GhENODL6;Verticillium wilt resistance;SA;ROS