Investigation on the evolutionary process integrating an endosymbiotic cyanobacterium into the host cellular system

2015 Fiscal Year Final Research Report

• Project Area: "Matryoshka"-type evolution of eukaryotes
• Project/Area Number: 23117006
• Research Category: Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)
• Allocation Type: Single-year Grants
• Review Section: Biological Sciences
• Research Institution: University of Tsukuba
• Principal Investigator: INAGAKI Yuji 筑波大学, 生命環境系, 准教授 (50387958)
• Co-Investigator(Kenkyū-buntansha): OBOKATA Junichi 京都府立大学, 大学院生命環境科学研究科, 教授 (50185667) ; KAMIKAWA Ryoma 京都大学, 大学地球環境学堂, 助教 (40627634)
• Project Period (FY): 2011-04-01 – 2016-03-31
• Keywords: オルガネラ進化 / ゲノム進化 / 共生 / 光合成 / 窒素固定

Outline of Final Research Achievements

Rhopalodiacean diatoms are known to possess cyanobacrerial endosymbionts (so-called spheroid bodies). In this study, we explored the evolutionary process transformed the endosymbiotic cyanobacterium into a part of the host cell. We obtained large-scale sequence data from both host and endosymbiont, and succeeded in shedding light on the mechanism which enables to maintain and control the endosymbiont in the host cell. We also searched for the free-living cyanobacterium that is the closest relative of spheroid bodies.
We also studied Paulinella chromatophora bearing a cyanobactrium-derived, photosynthetic organelle (so-called cyanelle), and investigated how the acquisition of cyanelle altered the host genome. We generated large-scale genomic, transcriptomic, and transcription start site data of P. chromatophora, and are working on these data to elucidate the precise process that allows the host cell to establish the photosynthetic organelle from an endosymbiotic cyanobacterium.

Free Research Field

微生物分子進化