Lysine 2‐hydroxyisobutyrylation orchestrates cell development and aflatoxin biosynthesis in Aspergillus flavus

Summary Lysine 2‐hydroxyisobutyrylation (K hib ) is a recently identified post‐translational modification (PTM) that regulates numerous cellular metabolic processes. In pathogenic microorganism, although glycolysis and fungal virulence are regulated by K hib , its potential roles in fungi remain to be elusive. Our preliminary results showed that levels of K hib fluctuate over time in Aspergillus flavus , which frequently contaminates crops and produces carcinogenic aflatoxins. However, the perception of K hib function in A . flavus is limited, especially in mycotoxin‐producing strains. Here, we performed a comprehensive analysis of K hib in A . flavus , and 7156 K hib sites were identified in 1473 proteins. Notably, we demonstrated that K hib of AflM, a key enzyme in aflatoxin biosynthesis, affected conidia production and sclerotia formation. Furthermore, aflM deletion impaired aflatoxin biosynthesis, and more importantly, strains in which K hib was mimicked by K to T mutation at K49, K179 and K180 sites showed reduced aflatoxin production compared with wild type and ΔaflM complementation strains. These results indicate that K hib at these sites of AflM negatively regulates aflatoxin biosynthesis in A . flavus . In summary, our study revealed the potential roles of K hib in A . flavus , and particularly shed light on a new way to regulate aflatoxin production via K hib .