ERF49 Gene Negatively Regulates Plant Resistance to Verticillium Wilt Through Modulation of Genes Involved in Lignin Biosynthesis

Cotton Verticillium wilt seriously threatens global cotton production, necessitating the development of resistant cultivars through molecular breeding. Members of the ethylene response factor (ERF) family function as pivotal transcriptional regulators of the ethylene signaling pathway, orchestrating plant defensive responses against pathogen invasion. Here, through comprehensive phenotypic and transcriptional analyses of lignin biosynthesis genes in AtERF49-overexpressing lines, loss-of-function mutants, dominant repressor plants, and GhERF49-silenced cotton plants (TRV-VIGS), we demonstrate that AtERF49 functions as a negative regulator of Verticillium wilt resistance. Overexpression of AtERF49 significantly compromised defense responses in Arabidopsis thaliana, whereas GhERF49 silencing enhanced cotton resistance to Verticillium wilt. Transcription analysis showed that ERF49-mediated susceptibility correlates with suppression of lignin biosynthesis-related genes following pathogen challenge, suggesting that ERF49 interferes with inducible cell wall fortification. These findings elucidate a previously unrecognized negative regulatory node linking ethylene signaling to lignin-mediated disease resistance, providing promising biotechnological targets for engineering durable Verticillium wilt resistance in cotton and related crops.