<i>GbWRKY11</i> Enhances Verticillium Wilt Resistance Through Activating <scp>Jasmonic Acid</scp> Biosynthesis in Cotton

The WRKY transcription factor is a key regulatory protein involved in defence hormone signalling and plays a pivotal role in plant hormone-mediated disease resistance. However, the specific mechanism by which WRKY transcription factors regulate the jasmonic acid (JA) pathway to confer resistance against Verticillium wilt in cotton remains poorly understood. In this study, we demonstrated that GbWRKY11 expression in Gossypium barbadense was induced by both Verticillium dahliae and methyl jasmonate (MeJA), and its encoded protein functioned as a nuclear transcription activator. Functional analyses revealed that GbWRKY11 enhances Verticillium wilt resistance by modulating JA pathway-related gene expression in both cotton and Arabidopsis. Exogenous MeJA application restored resistance in GbWRKY11-silenced plants, further supporting its role in JA-mediated immunity. Mechanistically, GbWRKY11 directly binds to the W-box motif in the promoter of GbLOX5, a key JA biosynthesis gene, and activates its transcription. Silencing GbLOX5 compromised cotton resistance to Verticillium wilt, confirming the importance of JA synthesis in this defence response. Our findings elucidate the molecular mechanism by which GbWRKY11 mediates immune responses against Verticillium wilt, providing novel insights into the genetic resources associated with disease resistance in G. barbadense.