Epigenetic Regulation of Cotton Plant Height by Histone Acetyltransferase GhHAT11 via Hormonal Pathway Modulation

Histone acetyltransferases (HATs) regulate transcription epigenetically through histone acetylation and play crucial roles in plant development. In this study, we identified a cotton HAT gene, GhHAT11, associated with plant height and investigated its regulatory functions and underlying mechanisms. Tissue-specific expression analysis showed that GhHAT11 was predominantly expressed in stems. Virus-induced gene silencing (VIGS) of GhHAT11 significantly reduced cotton plant height and internode cell length, whereas heterologous overexpression of GhHAT11 in Arabidopsis thaliana increased plant height, confirming its positive role in plant height regulation. Metabolomic and transcriptomic analyses revealed that silencing GhHAT11 decreased auxin and gibberellin (GA) levels, altered the expression of 3233 genes, downregulated genes involved in auxin and GA biosynthesis/signaling, and upregulated genes related to cytokinin metabolism and signaling. Furthermore, GhHAT11 positively regulates the expression of GA biosynthetic genes by maintaining H3K9ac levels at their promoters. Collectively, GhHAT11 regulates cotton plant height by coordinating gibberellin, auxin, and cytokinin pathways through modulation of hormone biosynthesis/signaling gene expression and H3K9ac-mediated control of GA biosynthetic genes.