Molecular dissection of interspecies incompatibility in the early reproductive process

2020 Fiscal Year Final Research Report

• Project Area: Determining the principles of the birth of new plant species: molecular elucidation of the lock-and-key systems in sexual reproduction
• Project/Area Number: 16H06467
• Research Category: Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)
• Allocation Type: Single-year Grants
• Review Section: Biological Sciences
• Research Institution: The University of Tokyo
• Principal Investigator: Takayama Seiji 東京大学, 大学院農学生命科学研究科(農学部), 教授 (70273836)
• Project Period (FY): 2016-06-30 – 2021-03-31
• Keywords: 植物 / シグナル伝達 / 生理学 / 生殖 / 受精 / 種間不和合性

Outline of Final Research Achievements

Focusing on the early reproductive process, starting from pollen adhesion, pollen germination, and resulting in pollen-tube growth, we tried to find out the key molecules involved in interspecies incompatibility. As a result, we succeeded in identifying a novel barrier molecule named SPRI1, functioning in the stigma of Arabidopsis thaliana. SPRI1 is an unrecognized molecule that actively rejects pollen grains from foreign species, providing another path to our understanding of interspecies barrier.　From another genetic screening, we found that pollen grains with defects in a phospholipid transporter failed to efficiently germinate and failed to induce compatible reactions in stigma. This finding gives us a new clue to elucidate the mechanism of cooperative reproductive process after compatible pollination.

Free Research Field

生物有機化学

Academic Significance and Societal Importance of the Research Achievements

本研究で解明を目指した初期受粉過程における種間生殖障壁分子は、いずれも自家不和合性研究の過程で我々が独自に存在を予見してきたものである。従来植物で同定された種間不和合性関連分子は、GCS1, LURE1など受動的に種間不和合性に関わるもののみであり、今回発見したSPRI1は能動的に種間不和合性に関わるという点で全く新しいタイプの種間不和合性因子である。新たな機構の存在とその解明への手掛かりを与える重要な基礎的知見となることが期待できる。さらに、本研究により得られる知見は、新種誕生に向けた種間障壁の人為的打破法の開発に直結するものであり、農業・育種面への波及効果も期待できる。