Genome-wide identification and expression analysis of BvHDA genes in sugar beet (Beta vulgaris L.) under salt and drought stress

Zinc ion (Zn2⁺)-dependent histone deacetylases (HDAs) are key epigenetic regulators of chromatin remodeling and serve crucial functions in plant stress adaptation. Although HDAs have been extensively studied in various species, their functional characterization and roles in abiotic stress responses in sugar beet (Beta vulgaris L.), an essential halophilic crop for food and sugar production, remain largely unclear. In this study, eight BvHDA genes in sugar beet were identified through a comprehensive bioinformatics analysis. The coding sequences of BvHDAs ranged from 984 to 1926 bp, with exon numbers varying between 3 and 14, which reflects their diverse structural organization. Based on phylogenetic analysis, BvHDAs can be classified into three distinct groups: Class I (three members), II (four members), and III (one member). Subcellular localization predictions suggested that BvHDAs were predominantly in the nucleus, which is consistent with their role in histone deacetylation. Expression profiling revealed that BvHDAs were responsive to salt and drought stress in roots and shoots, indicating their involvement in abiotic stress adaptation. To further explore the roles of BvHDAs, we overexpressed BvHDA4 in Arabidopsis, resulting in increased salt sensitivity, as characterized by dwarfism, etiolation, shortened roots, and reduced fresh weight. These findings indicate that BvHDA4 negatively regulates salt tolerance in plants. In summary, this study provides a systematic analysis of BvHDAs and highlights their importance in abiotic stress, establishing a research framework and valuable genetic resources for enhancing stress tolerance in sugar beet and other crops.