Elucidation of Gibberellin and sugar signals in flower induction in citrus

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K06018
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 39030:Horticultural science-related
• Research Institution: Saga University
• Principal Investigator: Kotoda Nobuhiro 佐賀大学, 農学部, 教授 (50355426)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: カンキツ / 花成誘導 / ジベレリン / 糖 / RNAseq / アミノ酸

Outline of Final Research Achievements

A decrease in the number of flowers in the following spring was confirmed in the plots sprayed with GA, supporting the results of previous reports. On the other hand, the number of new leaves tended to increase, suggesting that the decrease in tree vigor was alleviated by GA spraying. No significant difference was found for amino acids and sugars. It is necessary to increase the number of iterations and analyze in the future. Gene expression analysis by RNAseq confirmed that genes encoding PEBP family proteins and genes responsive to plant hormones were among the genes whose expression increased. On the other hand, among the genes whose expression was decreased, sugar metabolism-related enzyme genes were confirmed. These genes may have been involved in flower bud suppression in response to GA.

Free Research Field

園芸科学

Academic Significance and Societal Importance of the Research Achievements

果樹類の着果負担に対する花芽形成の反応は、果実形成による炭素源の減少や成熟果実に由来するジベレリン（GA）等のシグナル物質の放出に帰すると考えられているが詳しい分子メカニズムは分かっていない。本研究では、GAによる花成抑制効果を確認した上で、枝中における遊離糖や遊離アミノ酸の変動を調査したが有意差は見られなかった。しかし、遺伝子発現解析により、GA散布によりPEBPに属する遺伝子の発現上昇や糖関連遺伝子の発現低下が確認された。これらの結果はカンキツの花芽形成とジベレリンおよび糖との関係を明らかにする上で今後有用な情報となると思われる。