VdAHA1 positively regulate pathogenicity in Verticillium dahliae

AHA1 (activator of HSP90 ATPase) is a co-chaperone protein that mainly performs its function by interacting with the HSP90. The biological function of AHA1 has been widely reported in many species. In this study, we knocked out the <i>VdAHA1</i> gene of <i>V. dahliae</i> by homologous recombination method. The <i>VdAHA1</i> knockout mutants showed increased drug sensitivity to ergosterol synthesis pathway, significantly inhibiting ergosterol biosynthesis. The <i>VdAHA1</i> knockout mutant strain also showed decreased melanin in microsclerotia by reduced expression of microsclerotia and melanin related genes <i>Vaflm, Vayg1</i>, and <i>VdSCD</i>. The <i>VdAHA1</i> mutant showed decreased conidial production that were slightly damaged and showed more sensitivity to abiotic stresses such as temperature, SDS, CR, Sorbitol (SBT), NaCl, and KCl and decreased ATP contents. More importantly, the mutant was significantly less virulent to cotton than the wild type. This study identified the important functions of <i>VdAHA1</i> in the growth, stress resistance, and virulence.