Taxonomical and pathological characteristics of phytopathogenic fungus causing leaf blight of Cleyera japonica

Research Project

Project/Area Number	18K05746
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Review Section	Basic Section 40010:Forest science-related
Research Institution	Shimane University
Principal Investigator	KIHARA JUNICHI 島根大学, 学術研究院環境システム科学系, 教授 (40294368)
Co-Investigator(Kenkyū-buntansha)	陶山大志島根県中山間地域研究センター, 森林保護育成科, 専門研究員 (20502892)
Project Period (FY)	2018-04-01 – 2022-03-31
Project Status	Completed (Fiscal Year 2021)
Budget Amount *help	¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000) Fiscal Year 2020: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000) Fiscal Year 2019: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000) Fiscal Year 2018: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Keywords	サカキ / 輪紋葉枯病 / 繁殖体 / 分類 / 植物病原糸状菌 / 子のう盤 / 病害防除 / 病原性 / 紫外線 / 輪紋葉枯病菌 / 病理学的特性
Outline of Final Research Achievements	Basic research was performed regarding phytopathogenic fungus causing leaf blight of Cleyera japonica. This phytopathogenic fungus was suggested to belong to Sclerotiniaceae based on molecular phylogenetic analysis. Apothecia (sexual reproduction) of this fungus were firstly discovered in the nature. Specific detection methods of this fungus were established using Loop-Mediated Isothermal Amplification (LAMP). It was suggested that asexual reproduction via propagules （asexual reproduction）in this fungus could be major propagation style in the nature. Propagules formation of this fungus was promoted by near-UV irradiation on the leaf lesion. It was suggested that C. japonica could be major host plant of this fungus, although this fungus has broad host range.
Academic Significance and Societal Importance of the Research Achievements	常緑小高木であるサカキに病気を引き起こすサカキ輪紋葉枯病菌については、病害防除の基礎となる病原菌の生活環や病理学的特性が不明であった。本研究では、分子系統解析、および、子のう盤の発見により、サカキ輪紋葉枯病菌がキンカクキン科に属することを明らかにし、マイクロサテライトマーカーを用いた解析から、無性生殖が主な伝搬要因であることを示唆した。また、サカキ輪紋葉枯病菌は宿主範囲が広いものの、サカキのみがサカキ輪紋葉枯病菌の主要な宿主植物であることを示唆した。以上の研究成果は、サカキ輪紋葉枯病を防除する上で学術的意義があり、今後の防除対策に活かされることが期待される。