The expanded lineage-specific C2H2-homeobox transcription factors regulate microsclerotia formation and virulence in Verticillium dahliae
YongLin Wang: Beijing Forestry University
<div>The fungus <em>Verticillium dahliae</em> causes vascular wilt diseases on a broad range of plant species. <em>V. dahliae</em> is soilborne and widely distributed. It forms melanized microsclerotia that are capable of survival in the soil for more than ten years and can act as the primary source of infection. Genome-wide analyses of the C<sub>2</sub>H<sub>2</sub>-homeobox-encoding genes revealed significant expansion of this gene family in Verticillium. Out of seven genes identified, two of C<sub>2</sub>H<sub>2</sub>-homeobox genes were located in the lineage-specific region 2 of VdLs.17 isolate. In this study, we investigated the expansion of this gene family and the specific roles of these genes in microsclerotia formation and virulence in <em>V. dahliae</em>. Interestingly, though not encoded in the core genome, the LS-associated gene deletion mutant <em>VDAG_04891</em> showed deficiencies not only in virulence, but also in microsclerotia formation. Other gene deletion mutants exhibited undistinguishable phenotypes compared with the wild-type. Using RNA-Seq methods, we identified genes regulated by C<sub>2</sub>H<sub>2</sub>-homeobox during microsclerotia formation and plant infection. Furthermore, we explored the specific roles of each C<sub>2</sub>H<sub>2</sub>-homeobox transcription factors in growth, development and pathogenesis. The results reveal the biological significance of expanded C<sub>2</sub>H<sub>2</sub>-homeobox transcription factors and provide evidence to assign functions of the LS-associated transcription factor to roles in both microsclerotia formation and plant infection in <em>V. dahliae</em>.</div>
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