<i>OsLEA1b</i> Modulates Starch Biosynthesis at High Temperatures in Rice
2023
Gang Li | Ruijie Cao | Liuyang Ma | Guiai Jiao | Pengfei Chen | Nannan Dong | Xinwei Li | Yingqing Duan | Xiaoxue Li | Mingdong Zhu | Gaoneng Shao | Zhonghua Sheng | Shikai Hu | Shaoqing Tang | Xiangjin Wei | Yinghong Yu | Peisong Hu
High temperatures accelerate the accumulation of storage material in seeds, often leading to defects in grain filling. However, the mechanisms regulating grain filling at high temperatures remain unknown. Here, we want to explore the quality factors influenced by the environment and have identified a <i>LATE EMBROYGENESIS ABUNDANT</i> gene, <i>OsLEA1b</i>, a heat-stress-responsive gene in rice grain filling. <i>OsLEA1b</i> is highly expressed in the endosperm, and its coding protein localizes to the nucleus and cytoplasm. Knock-out mutants of <i>OsLEA1b</i> had abnormal compound starch granules in endosperm cells and chalky endosperm with significantly decreased grain weight and grain number per panicle. The <i>oslea1b</i> mutants exhibited a lower proportion of short starch chains with degrees of polymerization values from 6 to 13 and a higher proportion of chains with degrees from 14 to 48, as well as significantly lower contents of starch, protein, and lipid compared to the wild type. The difference was exacerbated under high temperature conditions. Moreover, <i>OsLEA1b</i> was induced by drought stress. The survival rate of <i>oslea1b</i> mutants decreased significantly under drought stress treatment, with significant increase in ROS levels. These results indicate that <i>OsLEA1b</i> regulates starch biosynthesis and influences rice grain quality, especially under high temperatures. This provides a valuable resource for genetic improvement in rice grain quality.
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