A chalcone synthase controls the verticillium disease resistance response in both Arabidopsis thaliana and cotton

Verticillium wilt is a devastating disease caused by the soil-borne fungus Verticillium dahliae that causes severe wilt symptoms in more than 400 plant species, including economically important cotton. However, the molecular mechanism of plant resistance to Verticillium remains unclear. In this study, we identified an Arabidopsis mutant, vsad1 ( verticillium sensitive and anthocyanin deficient 1 ), which showed more serious disease symptoms such as discoloration and chlorosis than wild-type Arabidopsis . vsad1 is a previously identified allele of the transparent testa 4 gene ( tt4 ), which encodes chalcone synthase (CHS), a key enzyme involved in the biosynthesis of flavonoids. Our results showed that VSAD1 expression was induced in response to Verticillium dahliae infection. Overexpression of VSAD1 partially recovered the anthocyanin accumulation phenotype of the vsad1–1 mutant. The concentration of V. dahliae increased and ROS accumulation decreased in the vsad1 mutant after infection with V. dahliae. Knockdown of the homologous gene GhCHS in cotton plants increased their susceptibility to V. dahliae infection. Thus, we conclude that VSAD1 is involved in the regulation of plant resistance to Verticillium wilt.