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Transcriptional regulation mediated by the balance of histone acetylation and deacetylation is fundamental in responding to environmental cues by impacting chromatin remodeling. Histone deacetylases (HDACs) are enzymes that remove acetyl groups from histone and non-histone proteins, thus restoring a tight chromatin structure. In pathogenic fungi, HDACs have been implicated in growth, secondary metabolite biosynthesis, and virulence. However, the role of HDACs in the mycotoxin fumonisin B1 (FB1)-producing fungus Fusarium verticillioides is poorly understood. In this study, we systematically characterized six F. verticillioides HDACs. An increased level of H4K16ac was observed in the deletion mutant of FvHOS2, which was associated with vegetative growth, conidiation, and virulence when infecting sugarcane and maize. FvRpd3 appeared to be essential for vegetative growth, while FvHda1 promoted growth, and both contributed to conidiation and pathogenicity. In contrast, FvSirt4 displayed a negative correlation with these processes. Additionally, the FB1 production was positively affected by FvHos2 and FvRpd3, but negatively impacted by Fvhda1, FvSir2, FvHst2, and FvSirt4 through the regulation of different key fumonisin biosynthetic (FUM) genes. Further findings indicate an association between FvSirt4 and FvSkb1, which is a histone methylase that positively regulates FB1 and pathogenicity. Moreover, as a global transcriptional regulator, over 2365 genes (~15% of the genome) enriched in multiple metabolic pathways were significantly downregulated in the ΔFvhos2 mutants relative to the wild type. Overall, our results suggest distinct roles of HDACs in regulating the growth, virulence, mycotoxin FB1 production, and gene expression in F. verticillioides. [ABSTRACT FROM AUTHOR]

Using gas chromatography-mass spectrometry (GC-MS), a metabolomic analysis of volatile metabolites of "19 Xiang" milk-ripe stage endosperm grains grown in Longchuan City and Lianshan City, Guangdong Province was conducted. The effect of origin on the formation of aroma compounds in aromatic rice was also explored by identifying the genes related to the formation of aroma compounds using transcriptome technology. Multivariate statistical analysis was performed on the original data using principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA). The results showed that the content of volatile substances in "19 Xiang" varied among grains planted in different places, exhibiting significant differences in the relative contents of 14 aroma substances. KEGG enrichment analysis revealed that the biosynthetic pathways of secondary metabolites significantly affected on the content of aroma substances. At the transcriptional level, taking the Lianshan group as the control, the samples of the Longchuan group had 56 significantly upregulated genes and 89 downregulated genes, which were mainly associated with biological processes such as catabolism of organic matter and polysaccharide metabolism. In conclusion, different planting environments greatly influence the content of aroma substances in aromatic rice, and carbohydrate metabolism activities and stress response-related mechanisms at the milking stage may be crucial factors regulating the content of aroma substances in the planting environment. [ABSTRACT FROM AUTHOR]