Elucidation of long-distance signals that transmit nitrogen nutritional status from shoot to root

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K05771
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 38010:Plant nutrition and soil science-related
• Research Institution: Shimane University
• Principal Investigator: Hachiya Takushi 島根大学, 学術研究院農生命科学系, 助教 (80709311)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 長距離シグナル / 全身的応答 / 窒素充足 / 硝酸シグナル / サイトカイニン / 転写因子

Outline of Final Research Achievements

In this study, we aimed to elucidate the signals that convey the nitrogen nutritional status from shoot to root in plants. Based on preliminary data, we focused on repressor X mRNA and isopentenyl cytokinin (iP-CK) as candidate signals. For this study, we constructed a simple and nondestructive nutritional manipulation transplantation system and proceeded with the analysis. As a result, no clear evidence was obtained that repressor X mRNA and iP-CK functioned as a signal. On the other hand, we found that the accumulation of nitrate ions in the shoot promoted shoot growth and defense responses mediated by iP-CK signaling, and that root-specific reduction of CK signaling promoted shoot growth.

Free Research Field

植物栄養生理学

Academic Significance and Societal Importance of the Research Achievements

本研究によって、地上部の硝酸イオンレベルの上昇にともなってイソペンテニル型サイトカイニンが合成されることがわかった。さらにイソペンテニル型サイトカイニンのシグナルを介して成長や防御応答が促進されることもわかった。これにより、植物が自身の窒素栄養状態に応じて成長や防御応答を制御する仕組みの一端がわかった。