Analysis of mechanisms of starch degradation in the stems for an enhancement of source function to rice grain filling.

2023 Fiscal Year Final Research Report

• Project/Area Number: 21H02174
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 39020:Crop production science-related
• Research Institution: Meijo University
• Principal Investigator: Hirano Tatsuya 名城大学, 農学部, 教授 (30319313)
• Co-Investigator(Kenkyū-buntansha): 黒川 裕介 名城大学, 農学部, 助教 (60851798)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: イネ / 茎部 / デンプン分解 / β-アミラーゼ / α-アミラーゼ / 染色体断片置換系統群 / 遺伝子連鎖解析

Outline of Final Research Achievements

Carbon sources for rice grain filling depend in part on non-structural carbohydrates (NSCs) stored temporarily in stems (leaf sheaths and culms). Three β-amylase genes, OsBAM2, OsBAM3 and OsBAM5, have been suggested to participate in the starch degradation in stems during the post-heading stage. In the present study, we characterized the tissue specificity and the response to sugar and plant hormones in the genes expression of OsBAM2, OsBAM3 and OsBAM5. The double-knockdown of OsBAM2 and OsBAM5 expression resulted in the repression of starch remobilization in stems during the post-heading stage. In addition, we performed the genetic linkage analysis to identify a gene, which positively regulate the starch remobilization in stems, on the sixth chromosome derived from indica rice cultivar IR64. As the result, the candidate gene are suggested to exist among 3.93 Mb region on the sixth chromosome.

Free Research Field

作物学

Academic Significance and Societal Importance of the Research Achievements

コメの需要は世界的に増加傾向であることからその収量性を向上させることは重要な課題である。穂のサイズが大きく、一穂穎花数が多いといったシンクサイズの増大は収量性向上には必要であるが、そのシンクを十分に満たすための同化産物の供給に関わるソース機能の充実も求められている。そこで本研究ではイネにおけるソース機能の向上に関わる知見を得るために研究を進め、出穂期までのイネ茎部に蓄積したデンプン分解に関与するβ-アミラーゼ遺伝子の機能の違いを明らかにした。また、インディカ品種由来の高いデンプン分解性を制御する遺伝子の単離に近づく成果も得られた。