AUTHOR=Lan Huahui , Wu Lianghuan , Fan Kun , Sun Ruilin , Yang Guang , Zhang Feng , Yang Kunlong , Lin Xiaolu , Chen Yanhong , Tian Jun , Wang Shihua 

TITLE=Set3 Is Required for Asexual Development, Aflatoxin Biosynthesis, and Fungal Virulence in Aspergillus flavus

JOURNAL=Frontiers in Microbiology

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2019.00530

DOI=10.3389/fmicb.2019.00530

ISSN=1664-302X

ABSTRACT=<p><italic>Aspergillus flavus</italic> is an opportunistic pathogenic fungus for both plant and animal that produces carcinogenic toxins termed aflatoxins (AFs). To identify possible genetic targets to reduce AF contamination, in this study, we have characterized a novel <italic>A. flavus</italic> Set3, and it shares sequence homology with the yeast protein Set3. The <italic>set3</italic> deletion mutants present no difference in growth rate but alterations in asexual development and secondary metabolite production when compared to the <italic>A. flavus</italic> wild type. Specifically, deletion of <italic>set3</italic> gene decreases conidiophore formation and conidial production through downregulating expression of <italic>brlA</italic> and <italic>abaA</italic> genes. In addition, normal levels of <italic>set3</italic> are required for sclerotial development and expression of sclerotia-related genes <italic>nsdC</italic> and <italic>sclR</italic>. Further analyses demonstrated that Set3 negatively regulates AF production as well as the concomitant expression of genes in the AF gene cluster. Importantly, our results also display that <italic>A. flavus</italic> Set3 is involved in crop kernel colonization. Taking together, these results reveal that a novel Set3 plays crucial roles in morphological development, secondary metabolism, and fungal virulence in <italic>A. flavus</italic>.</p>