Mechanisms of CWPO-C peroxidase function on the regulation of plant growth, differentiation, and branching

2019 Fiscal Year Final Research Report

• Project/Area Number: 17H03846
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Wood science
• Research Institution: Kyushu University
• Principal Investigator: Tsutsumi Yuji 九州大学, 農学研究院, 教授 (30236921)
• Co-Investigator(Kenkyū-buntansha): 河岸 洋和 静岡大学, グリーン科学技術研究所, 教授 (70183283)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: ペルオキシダーゼ / 植物ホルモン / オーキシン / 成長 / 分化 / リグニン

Outline of Final Research Achievements

The over-expression of CWPO-C (OE), a unique all-round peroxidase, in Arabidopsis were analyzed. The OE mutants showed delay of growth and gravitropism. And IAA contents were largely decreased. The results strongly suggest that CWPO-C catabolizes and inactivates IAA in vivo. This observation was further supported by the in vitro conversion of IAA by rCWPO-C. This finding may give a new insight of IAA catabolism in plant. On the other hand, The OE of CWPO-C in poplar showed the different phenotype, suggesting these two plant species have different regulatory mechanisms in IAA catabolism.
The effect of CWPO-C on the fairy compounds (FCs) those were recently proposed as possible new plant hormones, were also investigated. The CWPO-C over-expression mutant of Arabidopsis attenuated the positive growth effect of the exogenous AOH, one of FCs, and decrease endogenous AOH. It suggests that CWPO-C may also related to the metabolism and regulation of FCs in plant.

Free Research Field

樹木生化学

Academic Significance and Societal Importance of the Research Achievements

IAAの代謝不活化機構については、未解明の部分が残されておりIAAオキシダーゼによるOxIAAへの代謝変換やアミノ酸抱合体やグルコース抱合体への変換などが提案されている。一方本研究において、万能ペルオキシダーゼCWPO-C過剰発現体の表現型は、IAA欠乏状態の表現型とよく一致し、内生IAA量が著しく低下していたこと、組換体CWPO-CによるIAA代謝が確認されたことからCWPO-Cによる新たなIAA代謝経路が示唆された。IAAは植物の成長や分岐を制御する重要な因子であり、生産性と価値に大きな影響を持つため、その作用メカニズム解明は植物生産において非常に重要な知見になりうる。