Aspergillus flavus aswA, a gene homolog of Aspergillus nidulans oefC, regulates sclerotial development and biosynthesis of sclerotium-associated secondary metabolites

作者：Chang Perng Kuang^*; Scharfenstein Leslie L; Li Robert W; Arroyo Manzanares Natalia; De Saeger Sarah; Di Mavungu Jose Diana

来源：Fungal Genetics and Biology, 2017, 104: 29-37.

DOI：10.1016/j.fgb.2017.04.006

• Aspergillus flavus
• Zinc-finger protein
• Sclerotia
• Dihydroxyaflavinine
• Secondary metabolites

Aspergillus flavus aswA (AFLA_085170) is a gene encoding a Zn(II)(2)Cys(6) DNA-binding domain and a transcriptional activation domain, DUF3468. Disruption of aswA yielded strains that made a truncated gene transcript and generated a fungus that produced a greatly increased number of sclerotia. These sclerotia were odd-shaped and non-pigmented (white) and different from oval and pigmented (dark brown to black) mature sclerotia. Transcriptomic analysis of the Delta aswA strain grown on potato dextrose agar plates and Wickerham agar plates showed that expression of clustering genes involved in the biosynthesis of three sclerotium-associated secondary metabolites was down-regulated. These included gene clusters of asparasone, aflatrem, and aflavarin. In contrast, those of aflatoxin, cyclopiazonic acid and kojic acid were not affected. Metabolite analyses confirmed that the non-pigmented sclerotia contained aflatoxin and cyclopiazonic acid but not other aforementioned metabolites, three asparasone analogs and dihydroxyaflavinine commonly present in mature sclerotia. Impairment in aswA gene function stalls normal sclerotial development, which in turn prevents biosynthesis and accumulation of sclerotium-specific metabolites.

• 出版日期2017-7