Biological functions of the Zn2Cys6 transcription factor CsGcc1 in Colletotrichum siamense

Abstract:

[Background] Colletotrichum siamense (C. siamense) is a major fungal pathogen causing rubber anthracnose, which has led to substantial economic loss to the world rubber industry. The fungi-specific Zn₂Cys₆ transcription factor regulates the growth and development of fungi.[Objective] A Zn₂Cys₆ transcription factor CsGcc1 was identified from C. siamense, which is homologous to Gcc1 in Magnaporthe oryzae, and its functions were studied.[Methods] The CsGCC1-knockout mutant was developed by homologous recombination, and the functions of CsGcc1 were clarified based on the vegetative growth, H₂O₂ sensitivity, conidial production and germination, cellophane assay and pathogenicity analysis. [Results] CsGcc1 encoded a protein of 646 amino acids and the protein had a GAL4 domain. CsGCC1 was highly expressed in the mycelia and conidia after 36 h culture. The CsGCC1-knockout mutant had slow vegetative growth and low tolerance to H₂O₂. The conidium yield, conidium germination rate, and appressorium formation rate of the mutant were lower than those of the wild type. Cellophane assay showed that deletion of CsGcc1 could weaken the penetration ability of conidia. The virulence of the mutant to rubber leaves was attenuated. [Conclusion] The Zn₂Cys₆ transcription factor CsGcc1 is involved in regulating vegetative growth, oxidative stress, conidium development, and pathogenicity inC. siamense.