Organelle damage and UVB resistance induced by differences in CPD photolyase organelle localization among plants

2020 Fiscal Year Final Research Report

• Project/Area Number: 17H01872
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Risk sciences of radiation and chemicals
• Research Institution: Tohoku University
• Principal Investigator: HIDEMA Jun 東北大学, 生命科学研究科, 准教授 (20250855)
• Co-Investigator(Kenkyū-buntansha): 佐藤 修正 東北大学, 生命科学研究科, 教授 (70370921)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 紫外線UVB / 植物 / 光回復酵素 / 細胞内局在 / オートファジー / 葉緑体 / ミトコンドリア

Outline of Final Research Achievements

Cyclobutane pyrimidine dimer (CPD) photolyase, which repairs UVB-induced DNA damage, CPD, is essential for plants living in the sun. In the rice plant, rice CPD photolyase is expressed and targeted to not only the nucleus and the mitochondria but also the chloroplasts. This protein repairs UVB-induced CPDs in all three genomes. Therefore, rice CPD photolyase is a nuclear, mitochondrial and chloroplast triple-targeting protein. On the other hand, in some plants such as Arabidopsis thaliana, the transfer signal sequence for PHR to transfer to chloroplast is deleted, and it cannot be transferred to chloroplast. In such plants, autophagy, which removes damaged chloroplasts and mitochondria, is actively functioning, and Arabidopsis lacking autophagy shows UVB sensitivity. Therefore, autophagy plays an important role in UVB resistance.

Free Research Field

植物環境科学

Academic Significance and Societal Importance of the Research Achievements

本研究成果は、高等植物におけるCPD 光回復酵素の生体内における新たな機能やタンパク質のオルガネラ輸送に関わる新たなシグナル配列、輸送機構の発見にとどまるだけでない。「植物において太陽紫外線によって各々のオルガネラDNA に生じた傷が、生体内の諸過程、諸作用にどのような影響を及ぼし、致命的な障害を導いているのか？また障害に対してどのような修復応答を行い、生命を維持しているのか？」といった、放射線（含紫外線）生物学の根幹をなす概念を提唱し、さらには、環境農学的見地からUVB 環境耐性植物の創出へと発展させることも可能な成果である。