Remodeling Pollen Gametogenesis System based on the Study of Model Bryophyte

2023 Fiscal Year Final Research Report

• Project Area: Remodeling Plant Reproduction System by Cell Fate Manipulations.
• Project/Area Number: 20H05780
• Research Category: Grant-in-Aid for Transformative Research Areas (B)
• Allocation Type: Single-year Grants
• Review Section: Transformative Research Areas, Section (III)
• Research Institution: Kyoto University
• Principal Investigator: Yamaoka Shohei 京都大学, 生命科学研究科, 准教授 (00378770)
• Project Period (FY): 2020-10-02 – 2023-03-31
• Keywords: 生殖細胞分化 / 配偶子形成 / 転写因子 / 花粉 / ゼニゴケ / 陸上植物 / 進化

Outline of Final Research Achievements

Land plants form haploid multicellular bodies termed gametophytes after meiosis to produce germ cells. In this study, we showed that evolutionarily conserved BNB-LRL/DROP heterodimers are the key regulators for germ cell differentiation in the gametophytes of land plants. We also searched for the target genes of BNB-LRL/DROP in the Marchantia and Arabidopsis genomes. Phylogenetic studies suggest that the target gene candidates are also evolutionarily conserved among land plants. Several target gene candidates were cell wall-related enzyme genes that were likely involved in the formation of the unique structure of pollen. We further showed that the Nicotiana benthamiana BNB orthologs also regulate germ cell specification. Taken together, our findings suggest that the evolutionarily conserved genetic modules regulated by the BNB-LRL/DROP hetrodimers play important roles in germ cell differentiation in the gametophytes of land plants.

Free Research Field

植物分子細胞生物学、植物生殖生物学

Academic Significance and Societal Importance of the Research Achievements

陸上植物は、単相(n)と複相(2n)の両方において多細胞体を形成する「世代交代」を行う。配偶子形成において、植物は単相の多細胞体の中で生殖細胞を分化させるが、分子機構はほぼ不明であった。本研究では、生殖細胞分化の鍵因子としてBNB-LRL/DROPヘテロ二量体を同定し、標的分子機構を見出し、それらが陸上植物の系統間において広く保存されているという示唆を得た。また、これまで不明であった被子植物の花粉第１分裂における細胞運命決定の分子機構解明の端緒を開いた。本研究は、植物の有性生殖に関する基礎的な知見をもたらすものであり、今後の研究の進展により、農業・育種・バイオテクノロジーへの応用も期待できる。