Flavonoid biosynthesis as a conserved mechanism for Verticillium wilt resistance in cotton and maize

Verticillium wilt, caused by Verticillium dahliae , threatens cotton yield and fiber quality. While rotation with non-hosts like maize reduces disease incidence, its underlying mechanism remains poorly understood. This study employed metabolomics to analyze the root metabolomes of disease-resistant cotton (CR), susceptible cotton (CS), and maize (M) at 48 h post-inoculation with V. dahliae . The findings indicated that subsequent to the infection by V. dahliae , the flavonoid biosynthesis pathways in the roots of resistant cotton and maize were up-regulated . A total of 65 differentially accumulated metabolites (DAMs) were significantly enriched in this pathway, suggesting that flavonoid metabolism serves as a disease-resistance-related pathway functioning as an “inducible” defense mechanism in response to the infection. In vitro antimicrobial assays demonstrated that the key flavonoids—naringenin, naringenin chalcone, apigenin, and (+)-catechin—inhibited V. dahliae growth, with naringenin and naringenin chalcone showing potent inhibitory effects. Exogenous application of these flavonoids to susceptible cotton roots significantly reduced disease incidence by 35.9–61.9 % compared with controls. These findings suggest that flavonoid biosynthesis represents a conserved resistance mechanism in cotton and serves as the molecular foundation for disease suppression in maize-cotton rotations. This offers mechanistic understandings of flavonoid-mediated defense and strategies for the sustainable management of Verticillium wilt. • Flavonoid biosynthesis is a conserved defense in cotton and maize against V. dahliae. • Key flavonoids inhibit fungal growth and disrupt cell wall integrity of V. dahliae in vitro. • Exogenous application reduces Verticillium wilt incidence by 35.9–61.9% in susceptible cotton. • Upregulated root flavonoids explain disease suppression in maize-cotton crop rotations.