A dual-branch regulatory model: GhEIL7 coordinates ethylene and jasmonate pathways for defense against Verticillium dahliae

Ethylene (ET) and jasmonic acid (JA) synergistically orchestrate plant immunity against Verticillium dahliae . While ethylene-insensitive 3 (EIN3)/EIN3-Like (EIL) transcription factors govern ET signaling, how they evolutionarily and mechanistically bridge ET-JA crosstalk to confer disease resistance remains enigmatic in polyploid cotton ( Gossypium spp.) shaped by whole-genome duplication (WGD). Here, we conducted a comprehensive analysis of the EIN3/EILs in cotton, identifying 63 members across four species. Phylogenetic analysis clustered these genes into three major clades and nine subclusters, with WGD as the primary driver of family expansion and most members under purifying selection. Promoter cis-element analysis revealed enrichment of phytohormone- and stress-responsive elements, and expression profiling uncovered distinct tissue-specificity and pathogen-inducible expression patterns. A GhEIL7 gene, significantly upregulated upon V. dahliae infection, was cloned and localized to the nucleus, where it directly binds the GhGELP promoter to activate its transcription. GhEIL7 silencing significantly downregulated ET- and JA pathway genes ( GhERF1 , GhPDF1.2 , GhLOX , GhAOS1 , GhGELP ) in cotton, while heterologous overexpression in Arabidopsis thaliana significantly upregulated the corresponding orthologs. Consistently, GhEIL7 silencing reduced endogenous α-linolenic acid (α-LeA) and JA contents, whereas heterologous overexpression significantly elevated both metabolites. Mechanistically, GhEIL7 acts as a synergistic regulator of ET and JA pathways: it triggers the GhERF1- GhPDF1.2 transcriptional cascade to enhance disease resistance and upregulates GhGELP to promote JA precursor biosynthesis, driving JA-mediated defense. Collectively, these findings establish GhEIL7 as a signal-metabolism nexus that couples ET transcriptional activation with JA precursor biosynthesis to confer Verticillium wilt resistance, advancing our mechanistic understanding of phytohormone crosstalk and providing tractable molecular targets for disease-resistance breeding in cotton.