D- amino acid aminotransferase1 regulates grain chalkiness in rice by modulating endoplasmic reticulum stress response

• 成果类型: Article
• 署名作者: Dong, Hui; Lei, Jie; Tian, Yunlu; Liu, Juan; Yang, Hang; Jiang, Xiaokang; Zhang, Rushuang; Zhang, Yu; Chen, Rongbo; Bao, Yiqun; Liu, Feng; Ren, Yulong; Lu, Yaping; Liu, Xi; Liu, Shijia; Yang, Xue; Duan, Erchao; Teng, Xuan; Wang, Yunlong; Gu, Chuanwei; Zhang, Yipeng; Chen, Xiaoli; Zhang, Yunpeng; Xu, Hongyi; Sha, Rui; Xu, Xia; Li, Ruomeng; Li, Gongyu; Wang, Yihua; Wan, Jianmin
• 署名单位: Nanjing Agricultural University; Nankai University; Nanjing Agricultural University; Chinese Academy of Agricultural Sciences; Institute of Crop Sciences, CAAS
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.2519395123
• 发表日期: 2026-03-10
• 页码: e2519395123
• 关键词: rice; grain chalkiness; D-amino acid aminotransferase; endoplasmic reticulum stress; peptide/protein isomerization; gene-expression; conversion; encodes; peptide; alanine; cloning; wall

摘要

D-amino acids are key components of the bacterial cell wall and play important roles in neural communication and inflammatory responses in animals. However, knowledge about D-amino acid metabolism and physiological functions in plants is limited. Here, we isolated and characterized a rice D-amino acid aminotransferase1, OsDAAT1, which maternally regulates rice grain chalkiness through map-based cloning and a subsequent complementation test. We found that OsDAAT1 is highly expressed in the vascular tissue of rice nodes and is capable of interconverting different D-amino acids in vitro. Mutation of OsDAAT1 results in elevated D-alanine levels in stems, nodes, and developing grains. The disruption of D-amino acid metabolism subsequently leads to significantly altered peptide/protein isomerization, including some key enzymes involved in starch and protein biosynthesis. These changes trigger severe endoplasmic reticulum stress and ultimately leads to chalky grains. Furthermore, we identified OsDAAT1Hap1as a low-chalkiness haplotype, and historical frequency analysis suggests that OsDAAT1 may have undergone selection during rice domestication. Overall, our findings uncover a previously unrecognized role in D-amino acid metabolism in plants and facilitate the practical use of OsDAAT1 in grain appearance quality improvement in rice.