摘要Drought stress is a major environmental factor that limits the growth,development,and yield of rice(Oryza sativa L.).Histone deacetylases(HDACs)are involved in the regulation of drought stress re-sponses.HDA704 is an RPD3/HDA1 class HDAC that mediates the deacetylation of H4K8(lysine 8 of histone H4)for drought tolerance in rice.In this study,we show that plants overexpressing HDA704(HDA704-OE)are resistant to drought stress and sensitive to abscisic acid(ABA),whereas HDA704 knockout mutant(hda704)plants displayed decreased drought tolerance and ABA sensitivity.Transcriptome analysis revealed that HDA704 reg-ulates the expression of ABA-related genes in re-sponse to drought stress.Moreover,HDA704 was recruited by a drought-resistant transcription factor,WAX SYNTHESIS REGULATORY 2(OsWR2),and co-regulated the expression of the ABA biosyn-thesis genes NINE-CIS-EPOXYCAROTENOID DIOX-YGENASE 3(NCED3),NCED4,and NCED5 under drought stress.HDA704 also repressed the ex-pression of ABA-INSENSITIVE 5(OsABI5)and DWARF AND SMALL SEED 1(OsDSS1)by regu-lating H4K8ac levels in the promoter regions in re-sponse to polyethylene glycol 6000 treatment.In agreement,the loss of OsABI5 function increased resistance to dehydration stress in rice.Our results demonstrate that HDA704 is a positive regulator of the drought stress response and offers avenues for improving drought resistance in rice.