Identification of a Novel Pleiotropic Transcriptional Regulator Involved in Sporulation and Secondary Metabolism Production in Chaetomium globosum

Chaetoglobosin A (CheA), a well-known macrocyclic alkaloid with prominently highly antimycotic, antiparasitic, and antitumor properties, is mainly produced by Chaetomium globosum. However, a limited understanding of the transcriptional regulation of CheA biosynthesis has hampered its application and commercialization in agriculture and biomedicine. Here, a comprehensive study of the CgXpp1 gene, which encodes a basic helix-loop-helix family regulator with a putative role in the regulation of fungal growth and CheA biosynthesis, was performed by employing CgXpp1-disruption and CgXpp1-complementation strategies in the biocontrol species C. globosum. The results suggest that the CgXpp1 gene could be an indirect negative regulator in CheA production. Interestingly, knockout of CgXpp1 considerably increased the transcription levels of key genes and related regulatory factors associated with the CheA biosynthetic. Disruption of CgXpp1 led to a significant reduction in spore production and attenuation of cell development, which was consistent with metabolome analysis results. Taken together, an in-depth analysis of pleiotropic regulation influenced by transcription factors could provide insights into the unexplored metabolic mechanisms associated with primary and secondary metabolite production.