Functional analysis of BRLZ motif of the transcription factor CfHac1 in Colletotrichum fructicola

  Objective  Colletotrichum fructicola is a major pathogen causing anthracnose on Camellia oleifera, and leads to substantial losses annually. The domain analysis of transcription factor CfHac1 will help us understanding the CfHac1-regulated pathogenic mechanism of the pathogen and provide new insights to control this disease.

  Method  We constructed the domain deletion vector using point mutation technology and introduced it into the ΔCfhac1 mutant through the PEG-mediated protoplast transformation. The strains were selected by bleomycin and fluorescence, then the function was analyzed in C. fructicola.

  Result  The structure prediction revealed that CfHac1 contained one basic region-leucine zipper motif (BRLZ), which contained 58 amino acid residues. Comparing to the wide type and complemented strains, the mycelial growth rate, conidiation and appressorium formation rate of the Cfhac1^ΔBRLZ were significantly reduced, and the Cfhac1^ΔBRLZ strain was sensitive to dithiothreitol. The pathogenicity test showed that the Cfhac1^ΔBRLZ lost the ability to infect C. oleifera leaves, whose phenotype is consistent with ΔCfhac1 mutant.

  Conclusion  The results show that BRLZ is an important domain of CfHac1 and is essential for normal function of CfHac1 in C. fructicola.