The mechanism of recognition and fusion in Ulva gametes

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K14690
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 44010:Cell biology-related
• Research Institution: Hokkaido University
• Principal Investigator: ICHIHARA Kensuke 北海道大学, 北方生物圏フィールド科学センター, 特任助教 (60610095)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 有性生殖 / アロ認証 / 海藻 / 進化

Outline of Final Research Achievements

In this study, the proteins involved in the recognition and the fertilization between male and female gametes in Ulvophyceae, whose molecular mechanisms of reproductive processes have been poorly understood, were searched. At first, transcriptomic analysis during gametogenesis and proteomic analysis in flagellar and plasma membrane of male and female gamete was carried out. Through these analyses, genes involved in fertilization in land plants, such as GCS1 and GEX2 were detected. Furthermore, the genome-editing experiment for gene function analysis in Ulva was tried to establish. Polyethylene glycol (PEG)-mediated transfection method made it possible to efficiently deliver the preassembled CRISPR/Cas9 RNP to Ulva gametes. By this genome-editing method, gex2 deficient male mutants were obtained and male gametes released from these mutants can't fertilize with female gametes. The results suggest that GEX2 is a conserved gene that controls fertilization in the green plant lineage.

Free Research Field

藻類学

Academic Significance and Societal Importance of the Research Achievements

複雑な構造を持つ顕花植物ではなく生殖細胞が組織に覆われていない藻類を用い、受精の研究することで、植物の生殖細胞の相互認識や細胞の融合に関する新たな知見を得ることができると考えられる。本研究によって明らかになりつつある緑色植物の受精の基本原理の解明は、陸上植物の育種にも応用が可能であろうと考えられる。また日本は海に囲まれた海洋国家であるが、その沿岸域に生育する海藻類の応用研究が遅れている。本研究結果は藻類の生殖機構を明らかにするもので、藻類バイオマスを利用した二酸化炭素固定などの環境問題対策にも利用できる。