Genome-wide analysis of histone deacetylases (HDAC) gene family in seashore paspalum and functional analysis of PvHDAC15 in cadmium tolerance

The heavy metal cadmium (Cd) is highly detrimental to plant health given its high toxicity. The warm-season turfgrass Paspalum vaginatum Sw. is distinguished by its exceptional Cd tolerance. Although histone deacetylases (HDACs) are known to mediate plant abiotic stress responses, the underlying regulatory mechanisms and functions of individual HDAC members under Cd stress remain to be elucidated. In this study, 14 PvHDAC genes were retrieved from the seashore paspalum genome database, with their random distribution across chromosomes. Phylogenetic analysis classified these PvHDACs into three subfamilies, RPD3/HDA1, HD2, and SIR2, with 9, 3, and 2 members, respectively. Expression profiling showed that most PvHDAC genes were induced under Cd, drought, salt, and low-temperature stresses. Through genetic transformation of seashore paspalum with PvHDAC15 , it is observed that PvHDAC15 -overexpressing (OE) plants exhibited a higher leaf unfolding rate, increased photochemical efficiency, elevated relative water content, and reduced electrolyte leakage compared to wild-type (WT) plants under 500 µM CdCl₂ treatment. PvHDAC15 -OE plants also showed significantly reduced O 2 . − and H 2 O 2 accumulation, along with decreased activities of antioxidant enzymes relative to WT under Cd stress. Furthermore, PvHDAC15 was found to enhance the expression of three metallothionein (MT) genes ( PvMT1 , PvMT2 and PvMT3 ) under Cd stress. Collectively, this study establishes a basis for understanding the mechanism of Cd tolerance in plants regulated by histone deacetylase.