Histone 2-Hydroxyisobutyryltransferase Encoded by Afngg1 Is Involved in Pathogenicity and Aflatoxin Biosynthesis in Aspergillus flavus

Abstract

Aflatoxin, a carcinogenic secondary metabolite produced by Aspergillus flavus, is a significant threat to human health and agricultural production. Histone 2-hydroxyisobutyrylation is a novel post-translational modification that regulates various biological processes, including secondary metabolism. In this study, we identified the novel histone 2-hydroxyisobutyryltransferase Afngg1 in A. flavus, and explored its role in cell growth, development and aflatoxin biosynthesis. Afngg1 gene deletion markedly decreased lysine 2-hydroxyisobutyrylation modification of histones H4K5 and H4K8 compared with the control strain. Additionally, Afngg1 deletion inhibited mycelial growth of A. flavus, and the number of conidia and hydrophobicity were significantly decreased. Notably, aflatoxin B1 biosynthesis and sclerotia production were completely inhibited in the ΔAfngg1 strain. Furthermore, the pathogenicity of the ΔAfngg1 strain infecting peanut and corn grains was also diminished, including reduced spore production and aflatoxin biosynthesis compared with A. flavus control and Afngg1 complementation strains. Transcriptome analysis showed that, compared with control strains, differentially expressed genes in ΔAfngg1 were mainly involved in chromatin remodelling, cell development, secondary metabolism and oxidative stress. These results suggest that Afngg1 is involved in histone 2-hydroxyisobutyrylation and chromatin modification, and thus affects cell development and aflatoxin biosynthesis in A. flavus. Our results lay a foundation for in-depth research on the 2-hydroxyisobutyrylation modification in A. flavus, and may provide a novel target for aflatoxin contamination prevention.

Lysine 2‐hydroxyisobutyrylation proteomics analyses reveal the regulatory mechanism of CaMYB61‐CaAFR1 module in regulating stem development in Capsicum annuum L.

“…Here, we found that K hib ‐modified proteins were enriched in energy metabolism pathways, especially carbon fixation and glycolysis/gluconeogenesis. Microorganisms, such as Ustilaginoidea virens and Aspergillus flavus , are pathogenic to plants, and during the pathogenesis process, K hib modifications have been observed in their proteins (Chen, Li, et al., 2021; Wang, Liang, et al., 2023). Notably, the K hib ‐modified sites (such as H3K23/K36/K56/K79/K122 and H4K31/K79/K91) identified in Ustilaginoidea virens were also detected in our study, illustrating that these sites play an essential role in life activities across diverse organisms.…”

Proteome-Wide Analysis of Lysine 2-Hydroxyisobutyrylation in Aspergillus fumigatus

“…In Arabidopsis , Khib modification levels were found to decrease in the absence of light [ 25 ]. Furthermore, the deletion of hydroxyisobutyryltransferase Ngg1 in Aspergillus flavus significantly reduced the aflatoxin biosynthesis when compared to WT and Afngg1 complementation strains [ 26 ]. In Ustilaginoidea virens , mutations in Khib sites in the mitogen activated protein kinase (MAPK) UvSlt2 significantly diminished fungal virulence [ 27 ].…”

Efficient Inhibition of Aspergillus flavus to Reduce Aflatoxin Contamination on Peanuts over Ag-Loaded Titanium Dioxide

“…Peanuts, with rich nutrients and health value, are a type of important oil crop [ 5 ], but they are susceptible to aflatoxin contamination. Aflatoxins, with high toxicity, teratogenicity, and carcinogenicity, have been regarded as the most toxic mycotoxins found in food and agri-food [ 6 , 7 , 8 ], which not only threaten human health, but also can lead to huge economic losses [ 9 , 10 , 11 , 12 , 13 ]. Aflatoxins are secondary metabolites, mainly produced by Aspergillus flavus (A. flavus) in food and agri-food, especially peanuts and corn [ 14 , 15 ].…”