Verticillium dahliae transcription factor VdFTF1 regulates the expression of multiple secreted virulence factors and is required for full virulence in cotton

Abstract

Fungal transcription factors (TFs) implicated in the regulation of virulence gene expression have been identified in a number of plant pathogens. In Verticillium dahliae, despite its agricultural importance, few regulators of transcription have been characterized. In this study, a T-DNA insertion mutant with significantly reduced virulence towards cotton was identified. The T-DNA was traced to VdFTF1, a gene encoding a TF containing a Fungal_trans domain. Transient expression in onion epidermal cells indicated that VdFTF1 is localized to the nucleus. The VdFTF1-deletion strains displayed normal vegetative growth, mycelial pigmentation and conidial morphology, but exhibited significantly reduced virulence on cotton, suggesting that VdFTF1 is required exclusively for pathogenesis. Comparisons of global transcription patterns of wild-type and VdFTF1-deletion strains indicated that VdFTF1 affected the expression of 802 genes, 233 of which were associated with catalytic processes. These genes encoded 69 potentially secreted proteins, 43 of which contained a carbohydrate enzyme domain known to participate in pathogenesis during infection of cotton. Targeted gene deletion of one VdFTF1-regulated gene resulted in significantly impaired vascular colonization, as measured by quantitative polymerase chain reaction, as well as aggressiveness and symptom severity in cotton. In conclusion, VdFTF1, which encodes a TF containing a Fungal_trans domain, regulates the gene expression of plant cell wall degradation enzymes in V. dahliae, which are required for full virulence on cotton.

The Verticillium dahliae Sho1‐MAPK pathway regulates melanin biosynthesis and is required for cotton infection

“…Thus far, dozens of genes regulating virulence in V . dahliae (Fradin and Thomma, ; Klimes et al ., ; Zhang et al ., ) on various hosts have been identified.…”

“…This fungus infects host plants by directly penetrating roots and subsequently and systematically colonizing the water-conducting xylem vessels, until the pathogen switches to the reproductive mode when it produces conidia and toxins that interfere with the water movement that eventually results in leaf wilting and plant death (Klosterman et al, 2009;Zhang et al, 2019). Thus far, dozens of genes regulating virulence in V. dahliae (Fradin and Thomma, 2006;Klimes et al, 2015;Zhang et al, 2017b) on various hosts have been identified.…”

The transcription factor Zt107320 affects the dimorphic switch, growth and virulence of the fungal wheat pathogen Zymoseptoria tritici

“…Similarly, in the head blight‐causing fungus Fusarium graminearum 26% of 657 tested transcription factors showed a phenotypic effect during mycelial growth, conidia production and toxin production (Son et al , ). In summary, a number of transcription factors, which play important roles in host infection and pathogenesis, have been identified for several important crop pathogens (Chen et al , ; Okmen et al , ; Xiong et al , ; Zhang et al , ; Zhuang et al , ). In Z. tritici , however, only a few regulatory genes have been characterized.…”

Functional analyses of small secreted cysteine‐rich proteins identified candidate effectors in Verticillium dahliae

“…Verticillium dahliae is a notorious fungal pathogen that attacks a wide range of hosts, targets the xylem tissue, and causes verticillium wilt disease on many economically important crops (Klosterman et al , ; Inderbitzin and Subbarao, ). Previous studies have shown that secreted proteins probably play a critical role in the pathogenesis of V. dahliae (Fradin and Thomma, ; Chu et al , ; Chen et al , ; ; Zhang et al , ), and the function or the activity of several secreted proteins have been elucidated (de Sain and Rep, ; Klimes et al , ; Wang et al , ; Zhang et al , ). Similar to the mechanisms discovered in other phytopathogens, V. dahliae secretes proteins to manipulate host immunity during infection (de Jonge et al , ; Zhou et al , ; Santhanam et al , ; Liu et al , ; Gui et al , , ; Kombrink et al , ; Zhang et al , ; Qin et al , ).…”