The FlbA-regulated predicted transcription factor Fum21 of Aspergillus niger is involved in fumonisin production.

ABSTRACT: Aspergillus niger secretes proteins throughout the colony except for the zone that forms asexual spores called conidia. Inactivation of flbA that encodes a regulator of G-protein signaling results in colonies that are unable to reproduce asexually and that secrete proteins throughout the mycelium. In addition, the ?flbA strain shows cell lysis and has thinner cell walls. Expression analysis showed that 38 predicted transcription factor genes are differentially expressed in strain ?flbA. Here, the most down-regulated predicted transcription factor gene, called fum21, was inactivated. Growth, conidiation, and protein secretion were not affected in strain ?fum21. Whole genome expression analysis revealed that 63 and 11 genes were down- and up-regulated in ?fum21, respectively, when compared to the wild-type strain. Notably, 24 genes predicted to be involved in secondary metabolism were down-regulated in ?fum21, including 10 out of 12 genes of the fumonisin cluster. This was accompanied by absence of fumonisin production in the deletion strain and a 25% reduction in production of pyranonigrin A. Together, these results link FlbA-mediated sporulation-inhibited secretion with mycotoxin production.

SUBMITTER: Aerts D 

PROVIDER: S-EPMC5816093 | biostudies-literature | 2018 Mar

REPOSITORIES: biostudies-literature