Transcription factors containing both CH and homeobox domains play different roles in .

UNLABELLED

causes Verticillium wilt in more than 200 plant species worldwide. As a soilborne fungus, it forms melanized microsclerotia and colonizes the xylem of host plants. Our previous study revealed a subfamily of CH-homeobox transcription factors in , but their biological roles remain unknown. In this study, we systematically characterized the functions of seven CH-homeobox transcription factors in . Deletion of and significantly decreased the production of melanized microsclerotia, and knockout of and enhanced virulence. Loss of and increased conidium production, whereas loss of and did not affect growth, conidiation, microsclerotial formation, or virulence. Further research showed that VdChtf3 activated the expression of genes encoding pectic enzymes to participate in microsclerotial formation. In addition, VdChtf4 reduced the expression of to disturb the scavenging of superoxide radicals but induced the expression of genes related to cell wall synthesis to maintain cell wall integrity. These findings highlight the diverse roles of different members of the CH-homeobox gene family in .

IMPORTANCE

is a soilborne fungus that causes plant wilt and can infect a variety of economic crops and woody trees. The molecular basis of microsclerotial formation and infection by this fungus remains to be further studied. In this study, we analyzed the functions of seven C2H2-homobox transcription factors. Notably, VdChtf3 and VdChtf4 exhibited the most severe defects, affecting phenotypes associated with critical developmental stages in the disease cycle. Our results indicate that VdChtf3 is a potential specific regulator of microsclerotial formation, modulating the expression of pectinase-encoding genes. This finding could contribute to a better understanding of microsclerotial development in . Moreover, VdChtf4 was associated with cell wall integrity, reactive oxygen species (ROS) stress resistance, and increased virulence. These discoveries shed light on the biological significance of C2H2-homeobox transcription factors in 's adaptation to the environment and infection of host plants.