Starch serves as the primary storage substance in rice grains. Besides the substantial starch reserves in the endosperm of grains, leaves and sheaths also contain significant amounts of starch.
Recently, a team led by Dr. Hu Peisong, a researcher at the China National Rice Research Institute and an academician of the Chinese Academy of Engineering, made significant progress in understanding the regulatory mechanism of transient starch and storage starch biosynthesis in rice. Their related research findings were published online in Plant Communications. The study uncovered the dual regulation of transient starch in rice leaves and endosperm storage starch biosynthesis by two starch binding proteins, OsLESV and OsESV1, shedding light on the molecular mechanisms underlying rice quality and yield.
OsLESV and OsESV1 co-regulate both transient starch in rice leaves and storage starch in endosperm. Credit: Provided by the interviewee.
During the day, photosynthetic products in rice are stored as starch in leaf cells, while starch in leaves is degraded at night to provide energy for plant growth and development. Hence, starch in leaves is also known as transient starch. Transient starch in leaves serves as a crucial carbon source, vital for rice grain yield and quality formation. However, current research on rice starch primarily focuses on endosperm storage starch, and the molecular mechanisms underlying the synthesis and degradation of transient starch in rice leaves, as well as its regulation of rice yield and quality, remain unclear.
This study reveals that OsLESV and OsESV1 can bind to starch and interact with key enzymes involved in starch synthesis in rice leaves and endosperm, including GBSSI, GBSSII, and PPDKB, participating in the biosynthesis of transient starch in leaves and storage starch in endosperm, ultimately impacting rice quality and yield.
The findings enhance our understanding of the molecular mechanisms underlying transient starch biosynthesis in rice leaves, elucidating how transient starch biosynthesis and metabolism affect rice grain quality and yield, thereby providing important theoretical insights for genetic improvement of rice quality.
This research was supported by the National Key Technology R&D Program, the National Natural Science Foundation of China, and the Innovation Project of the Chinese Academy of Agricultural Sciences.
For more information, please refer to the related paper: https://doi.org/10.1016/j.xplc.2024.100893.
