The Fusarium graminearum Histone Acetyltransferases are Important for Morphogenesis, DON Biosynthesis, and Pathogenicity
Hao Zhang: Institute of Plant Protection, Chinese Academy of Agricultural Sciences
<div>Post-translational modifications of chromatin structure by histone acetyltransferase (HATs) play a central role in the regulation of gene expression and various biological processes in eukaryotes. Although HAT genes have been studied in many fungi, seldom of them have been functionally characterized in plant pathogenic ascomycete <em>Fusarium graminearum</em>. In this study, we identified and characterized four putative HATs (<em>FgRTT109</em>, <em>FgSAS2</em>, <em>FgSAS3</em> <em>FgGCN5</em>) in <em>F. graminearum</em>, the causal agent of <em>Fusarium</em> head blight of wheat and barley. We observed that all mutants inhibited the growth of <em>F. graminearum</em>. The Δ<em>FgSAS3</em> and Δ<em>FgGCN5</em> mutant increased sensitivities to oxidative and osmotic stresses. Additionally, Δ<em>FgSAS3</em> showed reduced conidia sporulation and perithecium formation than wide type PH-1. Δ<em>FgGCN5</em>, however, was unable to generate any conidia and lost the ability of perithecium formation. Our data showed that <em>FgSAS3</em> and <em>FgGCN5</em> are pathogenicity factors required for infecting wheat heads. Importantly, almost no DON was produced in Δ<em>FgSAS3</em> and Δ<em>FgGCN5</em> mutants, which was consistent with a significant downregulation of TRI genes expression levels. Furthermore, we showed that <em>FgSAS3</em> is indispensable for the acetylation of H3K4 and H3K14. <em>FgGCN5</em> is essential for the acetylation H3K9, H3K14, H3K18 and H3K27. RNA-seq analysis expression patterns of the two mutant strains provide insight into their function in development and metabolism. Results from this study clarify the functional divergence of HATs in <em>F. graminearum</em>, and may provide novel targeted strategies to control secondary metabolite expression and infections of <em>F. graminearum</em>.</div>
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