This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Supplemental material
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Guo, H.
Right arrow Articles by Xu, J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Guo, H.
Right arrow Articles by Xu, J.
Agricola
Right arrow Articles by Guo, H.
Right arrow Articles by Xu, J.

 Previous Article  |  Next Article 

Applied and Environmental Microbiology, November 2005, p. 7130-7138, Vol. 71, No. 11
0099-2240/05/$08.00+0     doi:10.1128/AEM.71.11.7130-7138.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.

Novel DNA Sequences from Natural Strains of the Nitrogen-Fixing Symbiotic Bacterium Sinorhizobium meliloti{dagger}

Hong Guo,1,2 Sheng Sun,1 Turlough M. Finan,1 and Jianping Xu1,2*

Center for Environmental Genomics, Department of Biology, McMaster University, Hamilton, Ontario, Canada L8S 4K1,1 Tropical Microbiology Laboratory, Hainan Medical College, Haikou, Hainan Province, 571101 People's Republic of China2

Received 26 February 2005/ Accepted 15 June 2005

Variation in genome size and content is common among bacterial strains. Identifying these naturally occurring differences can accelerate our understanding of bacterial attributes, such as ecological specialization and genome evolution. In this study, we used representational difference analysis to identify potentially novel sequences not present in the sequenced laboratory strain Rm1021 of the nitrogen-fixing bacterium Sinorhizobium meliloti. Using strain Rm1021 as the driver and the type strain of S. meliloti ATCC 9930, which has a genome size ~370 kilobases bigger than that of strain Rm1021, as the tester, we identified several groups of sequences in the ATCC 9930 genome not present in strain Rm1021. Among the 85 novel DNA fragments examined, 55 showed no obvious homologs anywhere in the public databases. Of the remaining 30 sequences, 24 contained homologs to the Rm1021 genome as well as unique segments not found in Rm1021, 3 contained sequences homologous to those published for another S. meliloti strain but absent in Rm1021, 2 contained sequences homologous to other symbiotic nitrogen-fixing bacteria (Rhizobium etli and Bradyrhizobium japonicum), and 1 contained a sequence homologous to a gene in a non-nitrogen-fixing species, Pseudomonas sp. NK87. Using PCR, we assayed the distribution of 12 of the above 85 novel sequences in a collection of 59 natural S. meliloti strains. The distribution varied widely among the 12 novel DNA fragments, from 1.7% to 72.9%. No apparent correlation was found between the distribution of these novel DNA sequences and their genotypes obtained using multilocus enzyme electrophoresis. Our results suggest potentially high rates of gene gain and loss in S. meliloti genomes.

* Corresponding author. Mailing address: Center for Environmental Genomics, Department of Biology, McMaster University, 1280 Main St. West, Hamilton, Ontario L8S 4K1, Canada. Phone: (905) 525-9140, ext. 27934. Fax: (905) 522-6066. E-mail: jpxu{at}mcmaster.ca.

{dagger} Supplemental material for this article may be found at http://aem.asm.org/.

Applied and Environmental Microbiology, November 2005, p. 7130-7138, Vol. 71, No. 11
0099-2240/05/$08.00+0     doi:10.1128/AEM.71.11.7130-7138.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Sun, S., Guo, H., Xu, J. (2006). Multiple gene genealogical analyses reveal both common and distinct population genetic patterns among replicons in the nitrogen-fixing bacterium Sinorhizobium meliloti.. Microbiology 152: 3245-3259 [Abstract] [Full Text]  


Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»