Functional analysis and application of nitrogen fertilizer-responsive rice amylases

Research Project

Project/Area Number	18K05605
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Review Section	Basic Section 39020:Crop production science-related
Research Institution	National Agriculture and Food Research Organization
Principal Investigator	Kuroda Masaharu 国立研究開発法人農業・食品産業技術総合研究機構, 生物機能利用研究部門, 上級研究員 (30355581)
Co-Investigator(Kenkyū-buntansha)	朝倉富子東京大学, 大学院農学生命科学研究科(農学部), 特任教授 (20259013)
Project Period (FY)	2018-04-01 – 2021-03-31
Project Status	Completed (Fiscal Year 2020)
Budget Amount *help	¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000) Fiscal Year 2020: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000) Fiscal Year 2019: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000) Fiscal Year 2018: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Keywords	コメ / 品質 / 窒素肥料 / アミラーゼ / デンプン / 遺伝子発現 / ゲノム編集 / イネ / 窒素追肥
Outline of Final Research Achievements	We tried to reveal the relationship among nitrogen fertilizer, nitrogen-induced rice amylase genes (Amy3E, BAM3Y, and BAMY5), and starch structure. The chain length distribution (CLD) of amylopectin branches changed by nitrogen fertilizer, whereas the appearance of starch granule did not change. For direct approach to gene function, various gene-modified rice lines were developed; i.e., (1)multiple knockout lines of above 3 amylases using genome editing, (2) transgenic lines harboring endosperm specific overexpression constructs of BAMY3 and BAMY5, (3) transgenic lines harboring chimeric constructs of GUS marker gene and promoter region derived from each 9 BAMY gene. There are no remarkable changes in grain appearance of above gene-modified rice lines.
Academic Significance and Societal Importance of the Research Achievements	窒素追肥によってコメ胚乳デンプンの鎖長分布が変化することを初めて明らかにした。一方で、デンプン粒の状態には明確な追肥の影響は見られなかった。鎖長分布を変化させる原因遺伝子として想定された3つの窒素応答性アミラーゼ（Amy3E, BAMY3、BAMY5）を中心に、様々な遺伝子改変系統群を作出した。研究期間中に原因遺伝子の特定まで至らなかったが、上記の遺伝子改変系統群を比較解析することで、コメデンプン集積機構と品質特性に果たすアミラーゼ群の新たな機能が明らかになり、新規デンプン特性を持つ品種開発に向けた基盤的知見が得られると期待できる。