Chitin Synthase Genes Are Differentially Required for Growth, Stress Response, and Virulence in .

Crop wilt disease caused by usually leads to serious yield loss. Chitin, an important component of most fungal cell walls, functions to maintain the rigidity of cell walls and septa. Chitin synthesis mainly relies on the activity of chitin synthase (CHS). Eight genes have been predicted in . In this study, we characterized the functions of these genes in terms of growth, stress responses, penetration, and virulence. Results showed that is important for conidia germination and resistance to hyperosmotic stress. Conidial production is significantly decreased in , , and mutants. , , , , , and genes are important for cell wall integrity, while all mutants are important for cell membrane integrity. All of the genes, except for , are required for the full pathogenicity of to and cotton plants. The in vitro and in vivo penetration of , , , and mutants was impaired, while that of the other mutants was normal. Overall, our results indicate that the genes exert diverse functions to regulate the growth and development, conidial germination, conidial production, stress response, penetration, and virulence in .