2024 Fiscal Year Final Research Report
The molecular mechanisms of plant immune evasion of the blast fungus by a novel enzyme and rice counter-defence.
| Project/Area Number |
22K05447
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 38030:Applied biochemistry-related
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| Research Institution | Kindai University |
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Principal Investigator |
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| Project Period (FY) |
2022-04-01 – 2025-03-31
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| Keywords | キチナーゼ / キチンオリゴ糖 / エリシター / 糖質加水分解酵素 / 植物ー微生物間相互作用 |
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| Outline of Final Research Achievements |
When rice plants become infected with the blast fungus Magnaporthe oryzae (M. oryzae), they secrete GH18 and GH19 chitinases. These enzymes degrade chitin, which is the main component of M. oryzae cell walls. This process makes the rice plants resistant to the fungus. Furthermore, the chitin oligosaccharides produced during this degradation process are recognised by cell surface receptors as elicitors, inducing an immune response. Conversely, M. oryzae secretes MoChia1, a GH18 chitinase that degrades the chitin oligosaccharides produced from its cell wall. This prevents the elicitors from being recognised by the receptors, thus evading plant immunity. In this study, we investigated the structure and function of MoChia1 to shed light on one aspect of M. oryzae's evasion of the plant immune system at the molecular level.
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| Free Research Field |
応用生物化学
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| Academic Significance and Societal Importance of the Research Achievements |
HPLCを用いてMoChia1によるキチンオリゴ糖の加水分解を詳しく調べた結果，本酵素は基質還元末端のβアノマーを選択的に認識し、最も還元末端側のグリコシド結合のみを切断することを明らかにした．MoChia1が分類されるGH18キチナーゼの基質認識・分解様式は一般的にエンド型であり，このような活性を示す酵素の発見は初めてであった。また，酵素の立体構造を決定し，MoChia1の特殊な基質認識機構の詳細を明らかにした．このような成果は，M. oryzaeによる植物免疫回避機構の一端を明らかにするだけでなく，糖質加水分解酵素学の発展に寄与するものと考えられた．
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