A transcription factor CgrStuA regulates vegetative growth, conidial production, germination, and hyphopodium formation of Colletotrichum graminicola

Abstract:

[Background] Colletotrichum graminicola (Ces.) G.W. Wilson is a major pathogenic fungus infecting plants, causing maize anthracnose. The APSES (Asm-1, Phd1, Sok2, Efg1 and StuA) transcription factor StuA, a fungal specific helix-loop-helix transcription factor, regulates the vegetative growth, conidial yield, germination, and pathogenicity of fungi. [Objective] To reveal the role of an APSES transcription factor CgrStuA identified in C.graminicola in the growth and development of C.graminicola. [Methods] The CgrstuA-deleted mutants were constructed by homologous recombination, and the obtained mutants were characterized in terms of the vegetative growth, conidial yield, germination, and pathogenicity. [Results] CgrstuA encoded a protein composed of 707 residues and containing a KilA-N domain. The CgrstuA-deleted mutants exhibited slow vegetative growth, decreased yields of two types of conidia, an extremely low germination rate of oval conidia, and significantly increased hyphopodia. However, there was no significant difference in the pathogenicity between the wild type and the mutants. [Conclusion] CgrStuA play important roles in the regulation of vegetative growth, conidial yield, germination, and hyphopodium formation of C.graminicola, while it did not affect the pathogenicity.