The <scp>R2R3</scp> ‐ <scp>MYB</scp> transcription factor <scp>GhMYB315</scp> associates with <scp>GhVQ28</scp> to enhance <scp>Verticillium</scp> wilt resistance in upland cotton by regulating phenylpropanoid metabolism

Verticillium wilt is a major vascular disease affecting cotton production. MYB transcription factors (TFs) play pivotal roles in plant immunity; however, the molecular mechanism by which R2R3-MYB TFs mediate Verticillium wilt resistance in cotton is poorly understood. Here, we identified an R2R3-MYB TF, GhMYB315, from upland cotton (Gossypium hirsutum L.) strongly upregulated upon infection by Verticillium dahliae (V. dahliae). CRISPR/Cas9-mediated mutation of GhMYB315 showed increased susceptibility to V. dahliae in cotton, whereas overexpression of GhMYB315 enhanced the resistance of Arabidopsis and cotton plants to V. dahliae. Transcriptome analysis revealed the upregulation of phenylpropanoid biosynthesis genes in GhMYB315-overexpressing cotton plants. Metabolomics analysis showed that overexpression of GhMYB315 promotes the accumulation of flavonoids and lignin and increases the content of guaiacyl and syringyl lignin monomers after inoculation with V. dahliae. Yeast two-hybrid screening revealed that a VQ motif-containing protein, GhVQ28, interacts with GhMYB315, and silencing GhVQ28 in GhMYB315-overexpressing cotton lines reduced resistance to Verticillium wilt. Our data indicate that the GhMYB315-GhVQ28 module mediates resistance to V. dahliae by positively regulating the phenylpropanoid pathway, revealing a novel module underlying the resistance strategy to Verticillium wilt.