Diversity and mechanisms underlying "subcellular niche segregation" of symbionts in whiteflies

2022 Fiscal Year Final Research Report

• Project/Area Number: 18K05673
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 39050:Insect science-related
• Research Institution: University of Toyama
• Principal Investigator: TSUCHIDA Tsutomu 富山大学, 学術研究部理学系, 准教授 (60513398)
• Project Period (FY): 2018-04-01 – 2023-03-31
• Keywords: コナジラミ / 菌細胞 / 共生細菌 / 棲み分け

Outline of Final Research Achievements

In bacteriocytes of the whitefly, two symbiotic bacteria are coexisted in the same bacteriocyte. They must play an essential role in the host survival and reproduction, but mechanisms for "subcellular niche segregation" of the bacteria were totally unknown. In this project, we attempted to elucidate the mechanism and to clarify the generality and evolution of the 'subcellar niche segregation' in whiteflies.
Imaging analyses revealed that that the two symbionts were separated by endoplasmic reticulum within the bacteriocyte. In earlier divergent phylogenetic groups, subcellular niche segregation between Portiera and Arsenophonus was observed. On the other hand, in the relatively recently diverged phylogenetic groups, two types of subcellular niche segregation (Portiera and Hamiltonella, or Portiera and Rickettsia) was detected. These findings suggest that replacement of the symbiotic bacteria have occurred repeatedly in whiteflies over a relatively short time interval.

Free Research Field

共生生物学

Academic Significance and Societal Importance of the Research Achievements

多くの昆虫では、その体内に、生存や繁殖の役割を担う必須の共生細菌を複数種棲まわせ ていることが知られている。しかし、これらの細菌は昆虫の別々の細胞や組織に収納されて いるのが一般的であり、同一細胞内での棲み分けという現象は従来まったく知られていなかった。本解析で明らかになった発見は、微生物の生態や共生の進化の理解に新たな観点を提示するもので ある。