昆虫寄生菌の分類と生態
昆虫寄生菌による害虫の微生物的防除
キーワード：昆虫寄生菌、土壌微生物、系統分類、シロアリ
2019.01.
| 西 大海（にし おうみ） | データ更新日：2023.09.27 |
主な研究テーマ
研究業績
主要原著論文
| 1. | NISHI Oumi*, SATO Hiroki, Isolation of Metarhizium spp. from rhizosphere soils of wild plants reflects fungal diversity in soil but not plant specificity, Mycology, 10.1080/21501203.2018.1524799, 10, 1, 22-31, 2018.09, [URL]. |
| 2. | NISHI Oumi*, IIYAMA Kazuhiro, YASUNAGA-AOKI Chisa, SHIMIZU Susumu, Abundance of the soil entomopathogenic fungus Metarhizium anisopliae sensu lato in agricultural field and forest soils in Japan, Current Research in Environmental & Applied Mycology, 10.5943/cream/8/4/6, 8, 4, 468-473, 2018.08, [URL]. |
| 3. | Oumi Nishi*, Hiroki Sato, Species diversity of the entomopathogenic fungi Metarhizium anisopliae and M. flavoviride species complexes isolated from insects in Japan, Mycoscience, 10.1016/j.myc.2017.06.008, 58, 6, 472-479, 2017.11, [URL], Phylogenetic analyses of insect-derived isolates of the Metarhizium anisopliae and M. flavoviride species complexes in Japan were conducted to reveal their species diversity. Fifty-seven isolates were identified as nine species, including one species first reported for Japan. Metarhizium pingshaense was the most frequently isolated species from this genus, and the 29 isolates of M. pingshaense came from six orders and 14 families of insects. New host–pathogen associations were found for two species with relatively narrow host ranges: Hymenoptera-M. pemphigi, Orthoptera- and Phasmatodea-M. majus.. |
| 4. | Oumi Nishi*, Susumu Shimizu, Hiroki Sato, Metarhizium bibionidarum and M. purpureogenum new species from Japan, Mycological Progress, 10.1007/s11557-017-1333-x, 16, 10, 987-998, 2017.10, [URL], Two new species of Metarhizium, M. bibionidarum and M. purpureogenum are described from Japan. Metarhizium bibionidarum is the phylogenetic sister species of M. pemphigi and a member of the M. flavoviride species complex. It is distinguished morphologically from M. pemphigi by its larger conidia. The species is based on a collection of an infected March fly larva (Diptera: Bibionidae) but is also known to occur on fruit beetle (Coleoptera: Scarabaeidae) encountered in France. Metarhizium purpureogenum was isolated from soil by plating and insect baiting methods and represents a unique phylogenetic lineage placed outside the M. anisopliae and M. flavoviride species complexes. Three isolates of M. purpureogenum excreted a distinctive red-purple pigment into agar medium when co-cultured with M. robertsii or Aspergillus oryzae.. |
| 5. | Oumi Nishi*, Kazuhiro Iiyama, Chisa Yasunaga-Aoki, Susumu Shimizu, Species associations and distributions of soil entomopathogenic fungi Metarhizium spp. in Japan, Mycology, 10.1080/21501203.2017.1386244, 8, 4, 308-317, 2017.10, [URL], Metarhizium Sorokīn (Hypocreales: Clavicipitaceae) is a genus of facultative parasites of insects found in soils from various environments and is used for pest management. Understanding the habitat selection of Metarhizium spp. is critical to improve the efficacy and persistence of these fungi as microbial insecticides. This study sought to determine the habitat preferences of Metarhizium spp. in Japan. We identified 302 isolates of Metarhizium spp. as eight species by a combination of PCR–RFLP and phylogenetic analysis of DNA sequences. M. pingshaense was the predominant species in Japan and was most frequently isolated from both forest and agricultural environments. On the other hand, M. brunneum and M. pemphigi were comparatively restricted to forest environments. A similar species association was detected in a small area that was intensively investigated, where 7 species including 14 genotypes were isolated from soil. The results of this study have revealed different habitat preferences among Metarhizium spp. in Japan.. |
| 6. | Oumi Nishi*, Kazuhiro Iiyama, Chisa Yasunaga-Aoki, Susumu Shimizu, Phylogenetic status and pathogenicity of Metarhizium majus isolated from a fruit beetle larva in Japan, Mycological Progress, 10.1007/s11557-015-1082-7, 14, 8, 2015.08, [URL], Some isolates of Metarhizium anisopliae sensu lato with large conidia (MALC), which was formerly known as M. anisopliae var. majus, from a scarabaeid host, such as isolates from the coconut rhinoceros beetle (Oryctes spp.), have a narrow host range and are particularly adapted to their original host. Despite recent taxonomic revisions of the genus Metarhizium on the basis of DNA sequences, variations in host preferences of MALC have not been linked to DNA sequence variations. This study focused on the phylogenetic status and pathogenicity of MALC isolated from the fruit beetle larva Protaetia orientalis submarumorea (Pos) in Japan to investigate the relationship between virulence and nucleotide sequence variation among MALC. On the basis of the results of the phylogenetic analyses of DNA sequences from five loci, we identified an isolate from Pos (Hn1) as M. majus, which comprised many isolates with large conidia from scarabaeid insects. In the virulence assay of genetically diverse Metarhizium isolates, only Hn1 and its most closely related isolates from soil showed pathogenicity to Pos; however, these Pos-pathogenic isolates showed weak virulence against silkworms. In the analysis of the intergenic spacer region of rDNA, the Pos-pathogenic isolates displayed unique sequence variation and were clearly distinguished from closely related lineages, including isolates from Oryctes sp., which formed a separate monophyletic group. These results indicate that the Pos-pathogenic isolates from Japan are particularly adapted to Pos and can be genetically distinguished from M. majus isolates from different scarabaeid insects.. |
| 7. | Oumi Nishi*, Kazuhiro Iiyama, Chisa Yasunaga-Aoki, S. Shimizu, Comparison of the germination rates of Metarhizium spp. conidia from Japan at high and low temperatures, Letters in Applied Microbiology, 10.1111/lam.12150, 57, 6, 554-560, 2013.12, [URL], The knowledge of the growth characteristics of entomopathogenic fungi at different temperatures is very important for understanding their ecology and field efficacy as biological control agents. However, the relationships between their DNA-based phylogenetic tree classifications and growth characteristics at different temperatures have not been adequately investigated. In this study, we compared the phylogenetic relationships between Metarhizium anisopliae sensu lato and M. flavoviride isolates obtained from soils in various environments in Japan and the germination rates of their conidia on agar medium in hot and cold conditions. The results showed that the 89 Japanese isolates belonged to the clade of eight species, according to the molecular phylogenetic analysis. The germination rates of isolates belonging to the M. brunneum and M. flavoviride var. pemphigi clades were higher at lower temperatures (9·7-11·0°C) and lower at higher temperatures (34·3-35·2°C) compared with the other six species. The isolates of these two species originated from different geographical regions in Japan, despite their uniform germination characteristics. This study detected the clear interspecific differences in the in vitro germination characteristics of the Japanese isolates of Metarhizium spp. at two different temperature regimes.. |
| 8. | Oumi Nishi, Keiichi Hasegawa, Kazuhiro Iiyama, Chisa Yasunaga-Aoki, Susumu Shimizu*, Phylogenetic analysis of Metarhizium spp. isolated from soil in Japan, Applied Entomology and Zoology, 10.1007/s13355-011-0045-y, 46, 3, 301-309, 2011.08, [URL], As a result of analyzing the internal transcribed spacer (ITS) and 5′ end of the EF-1α sequence of 145 isolates of Metarhizium spp. isolated from soil in Japan using selective agar medium, eight species were identified. ITS sequence analysis divided the isolates into three clades. Two were identified as M. flavoviride var. pemphigi and M. lepidiotae, respectively. EF-1α sequence analysis identified the other clades as six species: M. anisopliae, M. brunneum, M. guizhouense, M. majus, M. pingshaense and M. robertisii. The distribution of M. flavoviride var. pemphigi was restricted to forest or wood soil, and conidial sizes of M. guizhouense and M. majus were incongruent with the phylogeny based on the sequence of the 5′ end of EF-1α.. |
| 9. | 西大海,飯山和弘,青木智佐,清水進*, ヤマトシロアリReticulitermes speratus を用いた釣り出し法による土壌からの昆虫病原性糸状菌の分離, Entomotech, 35, 21-26, 2011.03, [URL]. |
| 10. | Oumi Nishi, Kazuhiro Iiyama, Chisa Yasunaga-Aoki, S. Shimizu*, Incongruence of EF-1α phylogeny and morphology between Metarhizium guizhouense and M. majus, Entomotech, 34, 19-23, 2010.02, [URL]. |
| 11. | Oumi Nishi, Kazuhiro Iiyama, Chisa Yasunaga-Aoki, S. Shimizu*, Virulence of Metarhizium anisopliae var. majus isolated from soils against termite, Coptotermes formosanus Shiraki, Japanese Journal of Environmental Entomology and Zoology, 21, 29-35, 2010.01, [URL]. |
| 12. | 西大海,飯山和弘,青木智佐,清水進*, 九州の土壌から分離したMetarhizium 属糸状菌の系統解析, Entomotech, 33, 49-53, 2009.02, [URL]. |
主要学会発表等
| 1. | 西大海, 和佐野直也, 青木智佐, メタリジウム菌の既知ゲノム情報を利用した高多型領域の選定と種内系統解析, 第66回日本応用動物昆虫学会大会, 2022.03. |
| 2. | 西 大海, 松岡拓, 青木智佐, 昆虫寄生菌のミカンキイロアザミウマに対する病原性とその土壌混合による影響, 第65回日本応用動物昆虫学会大会, 2021.03. |
学会活動
学会大会・会議・シンポジウム等における役割
2023.05.27～2023.05.28, 日本菌学会第67回大会, 座長.
2019.05.26～2019.05.26, 日本菌学会第63回大会, 座長、学生発表の審査.
学会誌・雑誌・著書の編集への参加状況
2020.01～2024.01, Journal of Applied Entomology and Zoology, 国際, 査読委員.
2019.06, Mycoscience, 国際, 編集委員.
学術論文等の審査
| 年度 | 外国語雑誌査読論文数 | 日本語雑誌査読論文数 | 国際会議録査読論文数 | 国内会議録査読論文数 | 合計 |
|---|---|---|---|---|---|
| 2023年度 | 1 | 1 | |||
| 2022年度 | 5 | 1 | 6 | ||
| 2020年度 | 6 | 1 | 7 | ||
| 2019年度 | 10 | 10 | |||
| 2018年度 | 3 | 3 | |||
| 2017年度 | 3 | 3 |
その他の研究活動
外国人研究者等の受入れ状況
2022.09～2022.10, 1ヶ月以上, University of Texas Rio Grande Valley, UnitedStatesofAmerica, 日本学術振興会.
受賞
第32回日本菌学会奨励賞, 日本菌学会, 2023.05.
生物資源環境科学府賞, 九州大学, 2011.03.
研究資金
科学研究費補助金の採択状況(文部科学省、日本学術振興会)
2023年度～2025年度, 基盤研究(C), 代表, 広宿主域の昆虫寄生菌における遺伝子破壊による選択性改変のための基礎研究.
2019年度～2020年度, 研究活動スタート支援, 代表, 昆虫寄生菌の土壌中における生残と感染に対する物理的ストレスと土壌静菌作用の影響.
2014年度～2016年度, 特別研究員奨励費, 代表, Ｍｅｔａｒｈｉｚｉｕｍ属糸状菌における寄生能の多面性とその進化的背景の解明.
2011年度～2013年度, 特別研究員奨励費, 代表, 昆虫病原性糸状菌の系統解析と生態特性.
共同研究、受託研究(競争的資金を除く)の受入状況
2023.04～2024.03, 連携, 南西諸島におけるMetarhizium属菌類の種多様性の解明と内生細菌探索のための抗生物質フリーな菌株ライブラリの作成.
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