The Fungi-specific histone Acetyltransferase Rtt109 mediates morphogenesis, Aflatoxin synthesis and pathogenicity in Aspergillus flavus by acetylating H3K9

Abstract

AbstractAspergillus flavusis a common saprophytic filamentous fungus that produces the highly toxic natural compound aflatoxin during its growth process. Synthesis of the aflatoxins, which can contaminate food crops causing huge losses to the agricultural economy, is often regulated by epigenetic modification, such as the histone acetyltransferase. In this study, we usedAspergillus flavusas an experimental model to construct the acetyltransferase genertt109knockout strain (△rtt109) and its complementary strain (△rtt109·com) by homologous recombination. The growth of △rtt109was significantly suppressed compared to the wild type (WT) strain and the △rtt109·com strain. The sclerotium of △rtt109grew smaller, and the amount of sclerotia generated by △rtt109was significantly reduced. The number of conidiums of △rtt109was significantly reduced, especially on the yeast extract sucrose (YES) solid medium. The amount of aflatoxins synthesized by △rtt109in the PDB liquid medium was significantly decreased We also found that the △rtt109strain was extremely sensitive to DNA damage stress. Through the maize seed infection experiment, we found that the growth of △rtt109on the surface of affected corn was largely reduced, and the amount of aerial mycelium decreased significantly, which was consistent with the results on the artificial medium. We further found that H3K9 was the acetylated target of Rtt109 inA. flavus. In conclusion, Rtt109 participated in the growth, conidium formation, sclerotia generation, aflatoxin synthesis, environmental stress response, regulation of infection ofA. flavus.The results from this study ofrtt109showed data for acetylation in the regulation of life processes and provided a new thought regarding the prevention and control ofA. flavushazards.