Transcriptomic profiles of the smoke tree wilt fungus Verticillium dahliae under nutrient starvation stresses.

Verticillium dahliae is a notorious plant pathogen that causes vascular wilt on more than 200 plant species. During plant infection, efficient pathogen nutrition during the interaction with the host is a requisite for successful infection. However, little attention has been focused on nutrient uptake and starvation responses in this fungus. Here, we used RNA-Seq to analyze the response of V. dahliae to nutrient starvation, including carbon and nitrogen depletion. Gene expression profile analysis showed that 1854 genes were differentially expressed under carbon starvation (852 upregulated and 539 downregulated genes) and nitrogen starvation (487 upregulated and 291 downregulated genes). Among the differentially expressed genes, genes involved in utilization or production acetyl-CoA, including glycolysis, fatty acid biosynthesis or metabolism, and melanin biosynthesis, were repressed under carbon starvation, whereas melanin biosynthesis genes were strongly induced under nitrogen starvation. These results, combined with VDH1 expression data, suggested that melanin biosynthesis and microsclerotia development were induced under nitrogen starvation, but microsclerotia development was suppressed under carbon starvation. Furthermore, many genes encoding carbohydrate-active enzymes and secreted proteins were induced under carbon starvation. Overall, the results improve our understanding of the response of V. dahliae to nutrient starvation and help to identify potential virulence factors for the development of novel disease control strategies.