Characterization of the biotrophic infection process of Rhizoctonia solani in plants

2023 Fiscal Year Final Research Report

• Project/Area Number: 21H02197
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 39040:Plant protection science-related
• Research Institution: Okayama University
• Principal Investigator: Noutoshi Yoshiteru 岡山大学, 環境生命自然科学学域, 教授 (70332278)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 紋枯病 / リゾクトニア病 / 感染生理 / ミナトカモジグサ / 殺生寄生 / 活物寄生 / エフェクター

Outline of Final Research Achievements

Rhizoctonia solani, a phytopathogenic fungus, infects a wide range of plant species and causes severe agricultural damage. To develop effective control measures, a thorough understanding of its infection strategies is essential. Our previous findings suggest that R. solani may undergo a biotrophic phase during its early infection process on leaves of monocotyledonous plants, in which it obtains nutrients from a living host. In this study, we found that this fungus employs small secreted proteins, known as effectors, that function to suppress host immunity. We also observed that R. solani can infect Arabidopsis thaliana, a model dicotyledonous plant, and that it induces resistance with phytohormones, suggesting that it infects necrotrophically, with minimal or no biotrophic interactions. Our results suggest that R. solani can discriminate between hosts and select different infection mechanisms as part of its infection strategy.

Free Research Field

植物病理学

Academic Significance and Societal Importance of the Research Achievements

R. solaniは菌糸融合反応や培養菌叢から分類される様々な系統を含む種複合体だが、それら分類と病原性に相関がないことが、本研究からも示された。おそらく気温や土壌成分などの環境要因が適合した場所で増えた菌株が病気を引き起こしていると考えられる。ただし宿主や組織特異性も存在するため、それらは生理学的・ゲノム科学的な比較解析で明らかにする必要がある。少なくともイネなどでは活物寄生を行うことから、そこを標的とした防除法を検討する道が拓かれた。同じ菌株でも宿主により感染機構を使い分ける事実は本菌の感染機構の複雑性を示しており、その背景の解明は植物病理学・微生物学・進化学における学術的価値を有する。