Complete genome of the uncultured Termite Group 1 bacteria in a single host protist cell

@article{citeulike:2731040, abstract = {Termites harbor a symbiotic gut microbial community that is responsible for their ability to thrive on recalcitrant plant matter. The community comprises diverse microorganisms, most of which are as yet uncultivable; the detailed symbiotic mechanism remains unclear. Here, we present the first complete genome sequence of a termite gut symbiont--an uncultured bacterium named Rs-D17 belonging to the candidate phylum Termite Group 1 (TG1). TG1 is a dominant group in termite guts, found as intracellular symbionts of various cellulolytic protists, without any physiological information. To acquire the complete genome sequence, we collected Rs-D17 cells from only a single host protist cell to minimize their genomic variation and performed isothermal whole-genome amplification. This strategy enabled us to reconstruct a circular chromosome (1,125,857 bp) encoding 761 putative protein-coding genes. The genome additionally contains 121 pseudogenes assigned to categories, such as cell wall biosynthesis, regulators, transporters, and defense mechanisms. Despite its apparent reductive evolution, the ability to synthesize 15 amino acids and various cofactors is retained, some of these genes having been duplicated. Considering that diverse termite-gut protists harbor TG1 bacteria, we suggest that this bacterial group plays a key role in the gut symbiotic system by stably supplying essential nitrogenous compounds deficient in lignocelluloses to their host protists and the termites. Our results provide a breakthrough to clarify the functions of and the interactions among the individual members of this multilayered symbiotic complex. 10.1073/pnas.0801389105}, author = {Hongoh, Yuichi and Sharma, Vineet K. and Prakash, Tulika and Noda, Satoko and Taylor, Todd D. and Kudo, Toshiaki and Sakaki, Yoshiyuki and Toyoda, Atsushi and Hattori, Masahira and Ohkuma, Moriya }, citeulike-article-id = {2731040}, doi = {10.1073/pnas.0801389105}, journal = {Proceedings of the National Academy of Sciences}, keywords = {451, bacteria, genome, metagenomics, protist, symbiosis, wga}, month = {April}, number = {14}, pages = {5555--5560}, posted-at = {2008-05-16 07:30:53}, priority = {3}, title = {Complete genome of the uncultured Termite Group 1 bacteria in a single host protist cell}, url = {http://dx.doi.org/10.1073/pnas.0801389105}, volume = {105}, year = {2008} }

TY - JOUR ID - citeulike:2731040 L3 - citeulike-article-id:2731040 TI - Complete genome of the uncultured Termite Group 1 bacteria in a single host protist cell JF - Proceedings of the National Academy of Sciences VL - 105 IS - 14 SP - 5555 EP - 5560 N2 - Termites harbor a symbiotic gut microbial community that is responsible for their ability to thrive on recalcitrant plant matter. The community comprises diverse microorganisms, most of which are as yet uncultivable; the detailed symbiotic mechanism remains unclear. Here, we present the first complete genome sequence of a termite gut symbiont--an uncultured bacterium named Rs-D17 belonging to the candidate phylum Termite Group 1 (TG1). TG1 is a dominant group in termite guts, found as intracellular symbionts of various cellulolytic protists, without any physiological information. To acquire the complete genome sequence, we collected Rs-D17 cells from only a single host protist cell to minimize their genomic variation and performed isothermal whole-genome amplification. This strategy enabled us to reconstruct a circular chromosome (1,125,857 bp) encoding 761 putative protein-coding genes. The genome additionally contains 121 pseudogenes assigned to categories, such as cell wall biosynthesis, regulators, transporters, and defense mechanisms. Despite its apparent reductive evolution, the ability to synthesize 15 amino acids and various cofactors is retained, some of these genes having been duplicated. Considering that diverse termite-gut protists harbor TG1 bacteria, we suggest that this bacterial group plays a key role in the gut symbiotic system by stably supplying essential nitrogenous compounds deficient in lignocelluloses to their host protists and the termites. Our results provide a breakthrough to clarify the functions of and the interactions among the individual members of this multilayered symbiotic complex. 10.1073/pnas.0801389105 KW - 451 KW - bacteria KW - genome KW - metagenomics KW - protist KW - symbiosis KW - wga AU - Hongoh, Yuichi AU - Sharma, Vineet AU - Prakash, Tulika AU - Noda, Satoko AU - Taylor, Todd AU - Kudo, Toshiaki AU - Sakaki, Yoshiyuki AU - Toyoda, Atsushi AU - Hattori, Masahira AU - Ohkuma, Moriya PY - 2008/04/08/ UR - http://dx.doi.org/10.1073/pnas.0801389105 ER -