Function of ROS on signal of bud dormancy of decidious fruit trees

• Project/Area Number: 18H02193
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 39030:Horticultural science-related
• Research Institution: University of Tsukuba
• Principal Investigator: Sugaya Sumiko 筑波大学, 生命環境系, 教授 (90302372)
• Co-Investigator(Kenkyū-buntansha): 瀬古澤 由彦 筑波大学, 生命環境系, 助教 (90361310)
• Project Period (FY): 2018-04-01 – 2023-03-31
• Project Status: Completed (Fiscal Year 2022)
• Budget Amount: ¥16,640,000 (Direct Cost: ¥12,800,000、Indirect Cost: ¥3,840,000); Fiscal Year 2022: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000); Fiscal Year 2021: ¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000); Fiscal Year 2020: ¥2,730,000 (Direct Cost: ¥2,100,000、Indirect Cost: ¥630,000); Fiscal Year 2019: ¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000); Fiscal Year 2018: ¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000)
• Keywords: 果樹 / ニホンナシ / 休眠 / 花芽 / 温度環境 / ROS / 植物ホルモン / 酸化還元 / 芽 / 過酸化物 / 落葉果樹 / 自発休眠

Outline of Final Research Achievements

To clarify the mechanism of abnormal flowering in deciduous fruit trees, effects of temperature on flower bud dormancy of the Japanese pears were investigated. Especially, effects of the hydrogen peroxide and fluctuation of the temperature during endodormancy period were investigated. From the results of the experiments, it was suggested that fluctuation of temperature on hydrogen peroxide, cytokinin and abscisic acid contents of the flower buds resulted on endodormancy breaking. Furthermore, results of the RNA-seq analysis indicated that high temperature conditions during low temperature exposure affect on dormancy-related genes, redox-related genes, and DNA methylation-related genes. It was suggested that these factors would relate to abnormal flowering of Japanese pears.

Academic Significance and Societal Importance of the Research Achievements

落葉果樹の花芽の開花異常は、花芽の休眠時の温度環境などが関わることが示唆されているが不明な点が多い。本研究では、温度条件が花芽や樹体の植物ホルモンや休眠関連遺伝子を含む多くの遺伝子発現に影響すること示し、花芽の開花異常のメカニズムに関わる多くの要因を示した点で学術的な意義があると考えられる。また、ニホンナシなどの落葉果樹の生産現場では、近年の異常気象や温暖化により、花芽の開花異常が報告されている。そのため、本研究の知見は、これらの課題を解決するための基礎的知見として意義があると考えられる。