Qualitative and quantitative analysis of infection and metabolic regulation of Farinocystis sp. in the host weevil, Euscepes postfasciatus

• Project/Area Number: 16K08100
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Insect science
• Research Institution: Kyushu University
• Principal Investigator: Chisa Yasunaga-Aoki 九州大学, 農学研究院, 教授 (20264103)
• Research Collaborator: FUKUI shota ; MATSUYAMA takashi ; CASSAL maximiano correa
• Project Period (FY): 2016-04-01 – 2019-03-31
• Project Status: Completed (Fiscal Year 2018)
• Budget Amount: ¥4,810,000 (Direct Cost: ¥3,700,000、Indirect Cost: ¥1,110,000); Fiscal Year 2018: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000); Fiscal Year 2017: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000); Fiscal Year 2016: ¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000)
• Keywords: Farinocystis sp. / Euscepes postfasciatus / オーシスト人工脱嚢法 / スポロゾイト単離 / 感染培養系 / パルスNMR法 / イモゾウムシ / 消化管抽出液 / プロテアーゼ / 感染伝播 / スポロゾイト / 昆虫病理 / 原虫 / 害虫管理 / 微生物的防除

Outline of Final Research Achievements

A Farinocystis neogregarine parasite was isolated from mass-reared colonies of the West Indian sweet potato weevil, Euscepes postfasciatus, at the facility of Okinawa Prefectural Plant Protection Center (OPPPC) in 2004. First, in order to evaluate the virulence of Farinocystis sp. against the host both qualitatively and quantitatively, artificial excystation of the oocysts was investigated. It revealed that a pretreatment with hexane was most effective for the oocyst excystation. Then, in order to evaluate a horizontal transmission through the oocysts, bioassays against various insect pests of sweet potato were conducted as well as host intestinal factors related to the oocyst excystation were investigated. Several proteases such as serine protease were involved in the oocyst excystation. In the pulse NMR experiment, metabolic changes and differences were detected between infected and non-infected host individuals.

Academic Significance and Societal Importance of the Research Achievements

本研究は、侵入害虫且つ難防除害虫のイモゾウムシから初めて分離された原虫を対象とした。この原虫病は達成間近の根絶防除事業を阻む深刻な原因となっており、本研究から得られた成果はイモゾウムシ根絶防除に寄与できるものである。また、本原虫の宿主はイモゾウムシに限られており、極めてユニークな生態をもって宿主個体・個体群での感染を維持している可能性が高い。そのため、本研究で明らかとなった原虫の生物学的諸性状は、新たなグレガリナ原虫特性の発見へと繋がるものである。また、イモゾウムシの代謝解析により明らかとなった原虫感染が宿主昆虫に与える影響の一端は、昆虫病理学に大いに貢献するものである。

Research Products

• [Journal Article] Pesticide Doses and Spraying Method for Optimal Pest Control in Paprika Cultivation (2018)
  • Author(s): Jin, N.Y., Lee, Y.K., Kim, H.J., Kim, Y.S., Youn, Y.N., Yasunaga-Aoki,C. and Yu, Y.M.
  • Journal Title: Journal of the Faculty of Agriculture, Kyushu University Volume: 63 Pages: 271-279
  • Open Access
• [Journal Article] cDNA Library Construction in the Multicolored Asian Ladybird Beetle, Harmonia axyridis (Coleoptera: Coccinellidae) for Gene Functional Analysis Using Gateway Cloning System (2018)
  • Author(s): Jung, Y.B., Kim, J.H., Kwon, H.R., Lim, H.S., Yu, Y.M., Yasunaga-Aoki, C. and Youn, Y.N.
  • Journal Title: Journal of the Faculty of Agriculture, Kyushu University Volume: 63 Pages: 281-292
  • Open Access
• [Journal Article] Selection and Characterization of Bacillus thuringiensis Strains with Biological Activity against Lycoriella ingenua (2018)
  • Author(s): Lee, Y.K., Jin, N.Y., Kim, H.J., Youn, Y.N., Yasunaga-Aoki,C. and Yu, Y.M.
  • Journal Title: Journal of the Faculty of Agriculture, Kyushu University Volume: 63 Pages: 293-302
  • Open Access
• [Presentation] Two New Bacillus thuringiensis Strains Toxic against Spodoptera frugiperda (Lep. Noctuidae) (2018)
  • Author(s): Cassal, M.C., Wiest, S.F., Yasunaga-Aoki, C. and Fiuza, L.M.
  • Organizer: The 2018 International Congress of Invertebrate Pathology and Microbial Control and the 51st Annual Meeting of the Society for Invertebrate Pathology
  • Int'l Joint Research