Is self-incompatibility in Citrus spp. governed by S-RNase?

2022 Fiscal Year Final Research Report

• Project/Area Number: 19H02949
• 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 Miyazaki
• Principal Investigator: Honsho Chitose 宮崎大学, 農学部, 准教授 (30381057)
• Co-Investigator(Kenkyū-buntansha): 稲葉 丈人 宮崎大学, 農学部, 准教授 (00400185) ; 牛島 幸一郎 岡山大学, 環境生命科学学域, 准教授 (20379720)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: カンキツ / 自家不和合性 / S-RNase / 果樹

Outline of Final Research Achievements

To elucidate the mechanism of self-incompatibility (SI) in Citrus species, the involvement of S-RNase-like T2 RNase genes in SI was examined. Recombinant protein of T2 RNase obtained from 'Hyuganatsu' was expressed in Escherichia coli and treated with germinated pollen in vitro, and it was observed that pollen tube elongation was inhibited. Genetic analysis of using seedlings obtained by out-cross of parents sharing one S allele confirmed that inheritance of several T2 RNase genes were consistent with the mode of the S allele inheritance. In addition, allelic diversity of T2 RNase genes were identified using 41 citrus varieties. Finally, it was concluded that these T2 RNase genes are S-RNase which regulates the SI of citrus plants.

Free Research Field

果樹園芸学

Academic Significance and Societal Importance of the Research Achievements

カンキツ属植物の自家不和合性については，その現象は古くから知られていたもののメカニズムに関する研究は長らく進展してこなかったが，本研究によってS-RNaseによって支配されているということが明らかになった．カンキツ属植物の自家不和合性は自家受粉による種子形成を制限するため，単為結果性カンキツを栽培する際の無核果生産に有用となる形質である，今後カンキツ属植物のS-RNase遺伝子型がより明らかになりDNAマーカーが開発されれば，新たな無核性カンキツ品種の育種の効率化が期待されるなど，社会的意義は大きいと考えられる．