Functional analysis of Granule-bound starch synthase II expressed in the vegetative organs of rice

2021 Fiscal Year Final Research Report

• Project/Area Number: 20K22576
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0602:Agricultural and environmental biology and related fields
• Research Institution: The University of Tokyo
• Principal Investigator: Morita ryutaro 東京大学, 大学院農学生命科学研究科(農学部), 助教 (30866075)
• Project Period (FY): 2020-09-11 – 2022-03-31
• Keywords: アミロース生合成 / 澱粉粒結合型澱粉合成酵素 / イネ / 澱粉

Outline of Final Research Achievements

Amylose is a linear molecule that is a component of the starch. Amylose is biosynthesized by granule-bound starch synthase (GBSS), and two GBSS isozymes, the endosperm-type GBSSI and the vegetative organ-type GBSSII, are encoded in the rice genome. In this study, we analyzed the function of GBSSII of rice using gbss2 knockout mutants. We found that the amylose content in the leaf blades and leaf sheaths of the gbss2 mutants was dramatically reduced, indicating that GBSSII plays a vital role in amylose biosynthesis in the vegetative organs of rice. However, starch content in the leaf blade and leaf sheath of the gbss2 mutants was not different from that of the wild type. Furthermore, the growth and yield of gbss2 mutant were not significantly different from those of the wild type. This indicates that amylose synthesis in the vegetative organs of rice is not essential for the efficient accumulation of photosynthates and the growth of rice plants.

Free Research Field

作物生理学

Academic Significance and Societal Importance of the Research Achievements

本研究により、これまで解明されていなかったイネ栄養器官におけるアミロース生合成機構の一端が明らかとなった。現在農業残差の多用途利用が検討されており、稲わらは飼料やバイオ燃料原料として注目を集めている。本研究で用いたgbss2機能欠損変異体の稲わらに蓄積する澱粉の詳細な物理化学的な性質の解析と従来の澱粉蓄積量を増加させる技術を組み合わせることで、多用途利用に適した澱粉が蓄積した新品種の開発に貢献できる。