Jinpeng Li, Danyang Zhao, Xiao Peng, Xinran Wu, Chenji Zhang, Huitao An, Wei Chu, Jingchen Lin, Zehui Liu, Qun Yang, Debiao Liu, Xiaoyu Liu, Wanghongan Jia, Yi Pei, Mingming Xin, Yingyin Yao, Weilong Guo, Huiru Peng, Zhongfu Ni, Qixin Sun, Xingbei Liu, Zhaorong Hu
Drought stress severely constrains wheat (Triticum aestivum L.) growth and productivity. Here, we identify the histone deacetylase TaHDA1 as a negative regulator of drought tolerance in wheat. We demonstrate that TaHDA1 interacts with and deacetylates the L-glutamate decarboxylase TaGAD1 at lysine 493, promoting its ubiquitination-dependent degradation and thereby suppressing γ-aminobutyric acid (GABA) accumulation. Loss of TaHDA1 function enhances TaGAD1 stability, increases GABA levels, and confers markedly improved drought tolerance, along with elevated grain GABA content. Integrated multi-omics analyses further reveal that TaHDA1 globally modulates H3K9 acetylation to orchestrate drought-responsive transcriptional programs. Notably, tahda1-ko mutants show a slight reduction in grain size under normal conditions, but maintain stable yield under drought stress. Our findings uncover a dual mechanism by which TaHDA1 integrates non-histone and histone deacetylation to balance growth and stress adaptation, providing a promising target for breeding drought-resilient and nutritionally enhanced wheat varieties.