ARS | Publication request: Deletion of the Aspergillus flavus orthologue of A. nidulans fluG reduces conidiation and promotes production of sclerotia but does not abolish aflatoxin biosynthesis

Submitted to: Applied and Environmental Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 10, 2012
Publication Date: August 17, 2012
Citation: Chang, P-K., Scharfenstein, L.L., Mack, B.M., Ehrlich, K. 2012. Deletion of the Aspergillus flavus orthologue of A. nidulans fluG reduces conidiation and promotes production of sclerotia but does not abolish aflatoxin biosynthesis. Applied and Environmental Microbiology. 78(21):7557-7563.

Interpretive Summary: Defects in fungal development often result in loss of secondary metabolite production. Aspergillus nidulans has been used as a molecular genetic model system for studying development of A. flavus and A. parasiticus, which produce carcinogenic aflatoxins. Deletion of the fluG gene of A. nidulans abolished sporulation causing a fluffy phenotype and rendered the fungus unable to produce sterigmatocystin, a precursor of aflatoxins. Our work showed A. flavus fluG deletion strains had decreased conidiation, elevated sclerotial production, and unaltered aflatoxin biosynthesis. The function of fluG in A. flavus is markedly different than in A. nidulans and that such potential variability should be taken into account when comparing the role of developmental regulatory factors in different fungi.

Technical Abstract: Aspergillus flavus fluG deletion strains showed decreased conidiation but had elevated sclerotial production. These developmental changes were not remediated by co-culturing with fluG-positive strains. The fluG mutant still retained its aflatoxin-producing ability. The A. flavus fluG gene functions distinctly from the A. nidulans fluG gene.