2023 Fiscal Year Final Research Report
Elucidation of systemic control mechanism of nodule development via long-distant mobile signals
Project/Area Number |
20H03283
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Research Category |
Grant-in-Aid for Scientific Research (B)
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Allocation Type | Single-year Grants |
Section | 一般 |
Review Section |
Basic Section 44030:Plant molecular biology and physiology-related
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Research Institution | National Institute for Basic Biology |
Principal Investigator |
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Project Period (FY) |
2020-04-01 – 2023-03-31
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Keywords | 根粒形成 / ミヤコグサ / 全身制御 / マイクロRNA / 窒素固定 / HAR1受容体 / シュート |
Outline of Final Research Achievements |
Legumes utilize a shoot-mediated signaling system to maintain a mutualistic relationship with rhizobia. In Lotus japonicus, shoot-to-root transfer of microRNA miR2111 that targets TML acting in roots has been proposed as a signaling factor for the systemic regulation of nodulation. However, the role of shoot-accumulating miR2111s has not been clearly shown. We showed that L. japonicus has seven miR2111 loci, including those mapped through RNA-seq. MIR2111-5 expression in leaves is the highest among miR2111 loci and clearly repressed after rhizobial infection depending on HAR1 receptor. MIR2111-5 knockout mutants show significantly decreased nodule numbers and miR2111 levels. Furthermore, grafting experiments using transformants demonstrate scions with altered miR2111 levels influence nodule numbers in rootstocks in a dose-dependent manner. Therefore, miR2111 accumulation in leaves through MIR2111-5 expression is required for HAR1-dependent systemic regulation of nodulation.
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Free Research Field |
植物生理学
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Academic Significance and Societal Importance of the Research Achievements |
窒素固定の手法としてハーバー・ボッシュ法が知られているが、マメ科植物に共生する根粒菌は常温常圧で効率よく窒素分子をアンモニアに変換することができる。その際、光合成による炭素同化産物を多く必要とするので、炭素同化と窒素固定とのバランスが植物の成長には極めて重要になる。根からの情報を「葉」でHAR1受容体が感知し、マイクロRNAの発現を制御することで、根粒形成を制御できることを見出した。 また、以上の受容体とマイクロRNAを介した根粒形成の全身制御モデルを動物の腫瘍に適用することができれば、腫瘍の初期形成を全身的に感知して、その発生と数を抑制することが可能になると思われる。
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