Requirement of LaeA for sporulation, pigmentation and secondary metabolism in Chaetomium globosum.

The global regulator LaeA has been confirmed to govern the production of secondary metabolites in fungi. Herein, we examined the role of LaeA in Chaetomium globosum. Similarly as observed in other filamentous, CgLaeA had a significant effect on the secondary metabolism. The ΔCglaeA mutant strain did not exhibit chaetoglobosin A, whereas its production was restored in the CglaeAC strain. In addition, CglaeA overexpression led to an increase in chaetoglobosin A production. Transcriptional examination of the mutants indicated that CgLaeA positively regulated the expression of pathway-specific transcription factor CgcheR, while another global regulator CgvelB was negatively regulated by CgLaeA. Furthermore, CgLaeA also affected the morphological phenotypes of fungi. The ΔCglaeA mutant strains exhibited decreased sporulation and pigmentation compared with the wild-type strain, whereas the phenotypes were restored in the CglaeAC strain. Moreover, OE::CglaeA exhibited increased levels of sporulation and pigmentation. Moreover, inhibition activity against phytopathogenic fungi affected by decreased mycotoxin production of the ΔCglaeA mutant strain.