MAP kinase pathways regulate stress responses as well as growth and development in most eukaryotic systems. MpkB MAP kinase in a model fungus Aspergillus nidulans has been known to coordinate sexual development and secondary metabolism, including sterigmatocystin (ST) production. In this study, however, the results of the ST production analysis of wild type and mpkB deletion mutants showed that the mpkB gene did not affect the ST production and ST related gene expression. Furthermore, ST production of ?mpkB, ?mkkB, and ?mpkB?mkkB mutants in the veA+ background were similar with wild type. Also, MpkB constitutive activation or inactivation mutants showed no significant effect on the ST production. Interestingly, ST production of mpkB and mkkB mutants was remarkably delayed in the veA1 background, suggesting that the ST production is affected primarily by the veA gene. Similarly, in Aspergillus flavus, MpkB ortholog AflmpkB mutant couldn’t produce any sclerotia, but it produced aflatoxin B1 normally. Taken together, the mpkB gene alone does not affect mycotoxin production such as ST in A. nidulans or aflatoxin B1 in A. flavus, indicating that the signaling of MpkB MAP kinase and mycotoxin production were governed by independent pathways.
Full conference title:
- Fungal Genetics Conference 30th (2019)