Molecular mechanism of sporophytic apomixis in citrus

Research Project

Project/Area Number	16K07608
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Research Field	Horticultural science
Research Institution	National Agriculture and Food Research Organization
Principal Investigator	SHIMADA Takehiko 国立研究開発法人農業・食品産業技術総合研究機構, 果樹茶業研究部門, ユニット長 (10355399)
Co-Investigator(Kenkyū-buntansha)	遠藤朋子国立研究開発法人農業・食品産業技術総合研究機構, 果樹茶業研究部門, 上級研究員 (50355400)
Project Period (FY)	2016-04-01 – 2019-03-31
Project Status	Completed (Fiscal Year 2018)
Budget Amount *help	¥4,810,000 (Direct Cost: ¥3,700,000、Indirect Cost: ¥1,110,000) Fiscal Year 2018: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000) Fiscal Year 2017: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000) Fiscal Year 2016: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
Keywords	多胚性 / カンキツ / アポミクシス / 単胚性 / MITE / トランスポゾン / アレル / 多胚 / マーカー / 園芸学
Outline of Final Research Achievements	Somatic embryogenesis in nucellar tissues is widely recognized to induce comprised multiple alleles that were divided into two types, polyembryonic alleles with a miniature inverted-repeat transposable element (MITE) insertion in the upstream region and monoembryonic alleles without it. CitRKD1 was transcribed in reproductive tissues of polyembryonic varieties with the polyembryonic allele. Loss of CitRKD1 function by antisense-overexpression abolished somatic embryogenesis in transgenic sweet orange and the transgenic T1 plants were confirmed to derive from zygotic embryos produced by self-pollination by DNA diagnosis. The MITE insertion in the upstream region of CitRKD1 might be involved in regulating the transcription of CitRKD1.
Academic Significance and Societal Importance of the Research Achievements	カンキツでは交雑育種法により新品種の開発が進められている。多胚性の個体を種子親に用いると、得られる実生個体のほとんどが種子親と同一のゲノムを持つクローン個体となり、交雑個体の獲得が極めて困難となる。多胚性は交雑組み合わせを限定する要因となっていることから、カンキツの育種を効率的に進めるためには、多胚性の原因遺伝子を解明し、芽生えの段階で胚性を識別可能なDNAマーカーの開発が求められている。