Membrane-anchoring of plastid DNA involves in regulation of nucleoid morphology and plastid gene expression

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K15819
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 44030:Plant molecular biology and physiology-related
• Research Institution: Hirosaki University (2021-2023); Kyoto University (2020)
• Principal Investigator: Fujii Sho 弘前大学, 農学生命科学部, 助教 (20867717)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: 葉緑体 / 核様体 / 遺伝子発現 / 膜脂質 / DNA結合タンパク質 / RNAポリメラーゼ

Outline of Final Research Achievements

During chloroplast development, the morphology of the plastid DNA-protein complex known as nucleoids changes in parallel with the induction of photosynthesis-associated genes. To uncover the mechanism underlying these processes, we first established a protocol to analyze the genome-wide DNA-binding pattern of plastid-encoded RNA polymerases. We also investigated the involvement of thylakoid formation in plastid gene expression and roles of membranous DNA-biding protein in chloroplast development. By analyzing the gene expression patterns in thylakoid-deficient mutants, we found that synthesis of thylakoid lipids is crucial for the transcription and translation in plastids. Our results indicate that the activation of plastid-encoded RNA polymerase depends on plastid lipid synthesis. We also revealed that the DNA-binding protein in the thylakoid are required for regulation of nucleoid morphology during chloroplast development and induction of gene expression under stressful conditions.

Free Research Field

植物生理学

Academic Significance and Societal Importance of the Research Achievements

植物の色素体は，器官や環境に応じて柔軟に分化することで，光合成やデンプン蓄積をはじめとする多様な代謝を担い，色素を蓄積して植物の多様ないろどりを創出する。本研究の成果は，チラコイド膜の形成や核様体の形態変化が，色素体の遺伝子発現制御に関与することを示している。植物の光合成や成長を最適化するには，色素体の遺伝子発現を適切に制御することが不可欠であるため，本研究の知見は人類が植物を食料や資源として活用する際の基礎的な情報となる。本研究で確立した色素体RNAポリメラーゼの機能をゲノムワイドに分析する方法は，任意の植物試料に適用可能であり，今後の植物学研究において広く活用されることが期待される。