論文

査読有り
2013年8月8日

Allying with armored snails: the complete genome of gammaproteobacterial endosymbiont.

The ISME journal
  • Satoshi Nakagawa
  • ,
  • Shigeru Shimamura
  • ,
  • Yoshihiro Takaki
  • ,
  • Yohey Suzuki
  • ,
  • Shun-ichi Murakami
  • ,
  • Tamaki Watanabe
  • ,
  • So Fujiyoshi
  • ,
  • Sayaka Mino
  • ,
  • Tomoo Sawabe
  • ,
  • Takahiro Maeda
  • ,
  • Hiroko Makita
  • ,
  • Suguru Nemoto
  • ,
  • Shin-Ichiro Nishimura
  • ,
  • Hiromi Watanabe
  • ,
  • Tomo-o Watsuji
  • ,
  • Ken Takai

記述言語
掲載種別
研究論文(学術雑誌)
DOI
10.1038/ismej.2013.131

Deep-sea vents harbor dense populations of various animals that have their specific symbiotic bacteria. Scaly-foot gastropods, which are snails with mineralized scales covering the sides of its foot, have a gammaproteobacterial endosymbiont in their enlarged esophageal glands and diverse epibionts on the surface of their scales. In this study, we report the complete genome sequencing of gammaproteobacterial endosymbiont. The endosymbiont genome displays features consistent with ongoing genome reduction such as large proportions of pseudogenes and insertion elements. The genome encodes functions commonly found in deep-sea vent chemoautotrophs such as sulfur oxidation and carbon fixation. Stable carbon isotope ((13)C)-labeling experiments confirmed the endosymbiont chemoautotrophy. The genome also includes an intact hydrogenase gene cluster that potentially has been horizontally transferred from phylogenetically distant bacteria. Notable findings include the presence and transcription of genes for flagellar assembly, through which proteins are potentially exported from bacterium to the host. Symbionts of snail individuals exhibited extreme genetic homogeneity, showing only two synonymous changes in 19 different genes (13 810 positions in total) determined for 32 individual gastropods collected from a single colony at one time. The extremely low genetic individuality in endosymbionts probably reflects that the stringent symbiont selection by host prevents the random genetic drift in the small population of horizontally transmitted symbiont. This study is the first complete genome analysis of gastropod endosymbiont and offers an opportunity to study genome evolution in a recently evolved endosymbiont.

リンク情報
DOI
https://doi.org/10.1038/ismej.2013.131
PubMed
https://www.ncbi.nlm.nih.gov/pubmed/23924784
PubMed Central
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3869010
URL
https://europepmc.org/articles/PMC3869010

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