OsLESV and OsESV1 promote transitory and storage starch biosynthesis to determine rice grain quality and yield

作者：Nannan Dong, Guiai Jiao, Ruijie Cao, Sanfeng Li, Shaolu Zhao, Yingqing Duan, Liuyang Ma, Xinwei Li, Feifei Lu, Hong Wang, Shiwen Wang, Gaoneng Shao, Zhonghua Sheng, Shikai Hu, Shaoqing Tang, Xiangjin Wei, Peisong Hu · 发表于：Plant Communications · 年份：2024 · DOI：10.1016/j.xplc.2024.100893 · 被引用次数：25 · 研究领域：Food composition and properties、Cassava research and cyanide

Transitory starch is an important carbon source in leaves, and its biosynthesis and metabolism are closely related to grain quality and yield. The molecular mechanisms controlling leaf transitory starch biosynthesis and degradation and their effects on rice (Oryza sativa) quality and yield remain unclear. Here, we show that OsLESV and OsESV1, the rice orthologs of AtLESV and AtESV1, are associated with transitory starch biosynthesis in rice. The total starch and amylose contents in leaves and endosperms are significantly reduced, and the final grain quality and yield are compromised in oslesv and osesv1 single and oslesv esv1 double mutants. Furthermore, we found that OsLESV and OsESV1 bind to starch, and this binding depends on a highly conserved C-terminal tryptophan-rich region that acts as a starch-binding domain. Importantly, OsLESV and OsESV1 also interact with the key enzymes of starch biosynthesis, granule-bound starch synthase I (GBSSI), GBSSII, and pyruvate orthophosphote dikiase (PPDKB), to maintain their protein stability and activity. OsLESV and OsESV1 also facilitate the targeting of GBSSI and GBSSII from plastid stroma to starch granules. Overexpression of GBSSI, GBSSII, and PPDKB can partly rescue the phenotypic defects of the oslesv and osesv1 mutants. Thus, we demonstrate that OsLESV and OsESV1 play a key role in regulating the biosynthesis of both leaf transitory starch and endosperm storage starch in rice. These findings deepen our understanding of the mol...