Analyses of molecular mechanisms in the synergid-endosperm fusion.

2018 Fiscal Year Final Research Report

• Project/Area Number: 16H06173
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Single-year Grants
• Research Field: Morphology/Structure
• Research Institution: Yokohama City University
• Principal Investigator: Maruyama Daisuke 横浜市立大学, 木原生物学研究所, 助教 (80724111)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 花粉管 / 卵細胞 / 重複受精 / 細胞融合 / シロイヌナズナ / 助細胞 / 胚乳

Outline of Final Research Achievements

Cell-fusion between the persistent synergid and the endosperm (Synergid-Endosperm fusion, SE fusion) appears to be one of the important events in the cessation of pollen tube attraction in fertilized ovule. To elucidate molecular mechanism, we performed a pharmacological analysis and forward genetics.
Transcriptional or translational Inhibitors severely impaired induction of the SE fusion in fertilized ovules. Frequency of SE fusion also reduced by a treatment of roscovitine, an inhibitor of Cyclin-Dependent Kinases (CDKs). These data indicates an importances of post-fertilization de novo gene expression as well as mitotic entry in the induction of SE fusion.
In the forward genetics approach, we generated a reporter line that labels mitochondria and nucleus of the synergid cells with different colors, and induced point mutations by an EMS treatment. We isolated eight mutants that frequently showed a defect in SE fusion among 2,201 M1 individuals.

Free Research Field

植物生殖学

Academic Significance and Societal Importance of the Research Achievements

助細胞胚乳融合は被子植物の成長の過程でも珍しい細胞融合現象である。その仕組みの一端を示すとともに今後の詳しい解析につながる本研究は、植物が細胞を融合するために細胞壁や細胞膜をどのように制御するかを理解するために役立つ。また、花粉管誘引停止の制御を理解する基礎的な研究として、本研究成果は将来的に、卵細胞を2つの精細胞で受精させたり、卵細胞と中央細胞を別々の精細胞で受精させる技術の開発の発展に寄与すると期待される。