VdERG2 was involved in ergosterol biosynthesis, nutritional differentiation and virulence of Verticillium dahliae

Abstract

The ergosterol biosynthesis pathway plays an important role in model pathogenic bacteria Saccharomyces cerevisiae, but little is known about the biosynthesis of ergosterol in pathogenic fungus Verticillium dahliae. In this study, we identi ed the VdERG2 gene encoding sterol C-8 isomerase from V. dahliae and investigated its function in virulence by generating gene deletion mutants (ΔVdEGR2) and complemented mutants (C-ΔVdEGR2). Deletion of VdERG2 reduced ergosterol content. The conidial germination rate and conidial yield of ΔVdERG2 decreased signi cantly, and abnormal conidia were produced. In spite of VdERG2 did not affect the utilization of carbon sources by V. dahliae, but ΔVdERG2 observed a decrease in melanin production when cellulose and pectin were used as sole carbon sources, respectively. The ability of mutants ΔVdERG2 to produce microsclerotia and melanin decreased and the knockout of VdERG2 led to a signi cant decrease in the expression of microsclerotia and melanin-related genes Va M, Vayg1, VDH1, VdLAC, VdSCD and VT4HR. In addition, mutants ΔVdEGR2-1 and ΔVdEGR2-2 were very sensitive to congo red (CR), sodium dodecyl sulfate (SDS) and hydrogen peroxide (H 2 O 2 ) stresses, indicating that VdEGR2 was involved in cell wall and oxidative stress response. The absence of VdERG2 weakened the penetration ability of mycelium on cellophane and affected the growth of mycelium on cellophane. Although ΔVdERG2 could infect cotton, its pathogenicity was signi cantly impaired. These phenotypic defects in ΔVdERG2 could be complemented by reintroduction of a fulllength VdERG2 gene. In summary, as a single conservative secretory protein, VdERG2 played a crucial role in ergosterol biosynthesis, nutritional differentiation and virulence in V. dahliae.

The role of VdSti1 in Verticillium dahliae: insights into pathogenicity and stress responses

“…Knockout of VdUGP and VdEPG1 in V. dahliae , which affect membrane integrity, hindered growth under SDS stress ( Deng et al, 2020 ; Liu et al, 2023 ). In addition, reduced ergosterol biosynthesis was observed in V. dahliae upon the knockout of VdERG2 , emphasizing its role in ergosterol production ( Lv et al, 2023 ). Our study demonstrated that the knockout of VdSti1 led to reduced ergosterol biosynthesis in V. dahliae and increased sensitivity to SDS and CR stress.…”

“…To generate the knockout mutant strain, upstream and downstream flanking sequences of the target gene were amplified from the genomic DNA of V. dahliae . An hygromycin resistance cassette (HPH) was amplified from the B303 vector and cloned into the B303 vector ( Lv et al, 2023 ). The constructed vector was then transformed into Agrobacterium tumefaciens AGL1, and the knockout mutant was generated through Agrobacterium -mediated transformation (ATMT) ( Wang et al, 2016a ).…”