2022 Fiscal Year Final Research Report

Mechanism of spread of Rice Orange Leaf Phytoplasma in Southeast Asia

Research Project

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Project/Area Number	18KK0171
Research Category	Fund for the Promotion of Joint International Research (Fostering Joint International Research (B))
Allocation Type	Multi-year Fund
Review Section	Medium-sized Section 39:Agricultural and environmental biology and related fields
Research Institution	Nagoya University
Principal Investigator	CHIBA Sotaro 名古屋大学, 生命農学研究科, 准教授 (70754521)
Co-Investigator(Kenkyū-buntansha)	田中利治名古屋大学, 農学国際教育研究センター, 客員教授 (30227152) 大井崇生名古屋大学, 生命農学研究科, 助教 (60752219) 佐藤育男名古屋大学, 生命農学研究科, 助教 (70743102)
Project Period (FY)	2018-10-09 – 2023-03-31
Keywords	イネオレンジ葉ファイトプラズマ / ROLP / 発生分布 / 拡散メカニズム
Outline of Final Research Achievements	As cold-sensitive insects expand their habitat due to climate change, phytoplasma-related diseases in the tropics and subtropics transmitted by these insects are expected to move northward, and there is concern that rice orange leaf phytoplasma (ROLP), which occurs in Southeast Asian countries, may invade Japan. In this study, we investigated the ROL disease occurrence and ROLP genotypes in Southeast Asian countries, and we found that ROLP originated in Thailand and neighboring countries and that only a particular ROLP genotype is expanding to near East Asia, probably by the contributions of newly identified insect vectors such as a green leafhopper in addition to previously reported insects. In addition, the behavior of the pathogen in plants and some physiological changes in affected plants were clarified, and important findings were obtained for disease control.
Free Research Field	植物保護学　植物病理学　ウイルス学
Academic Significance and Societal Importance of the Research Achievements	ROLは、1960-80年頃にアジア各地で発生が確認されていたが、その後は中国南東部での発生報告のみに留まっていた。近年の東南アジアにおけるROL発生報告増加の背景にはイネの生育ステージ全体を通して安定的に高い密度で存在する新規媒介昆虫（Nephotettix virescens）が病原を維持すること、日本近傍には特定の遺伝型をもつROLPが感染域を拡大していることが明らかとなり、日本への侵入警戒対象とすべき昆虫（Nephotettix属）と病原菌遺伝型を特定した。また、ROLPの病原性の実態についてその一端を明らかにし、単子葉植物におけるファイトプラズマ病の知見集積に貢献した。