sourceforge.net/. Nucleic acids multiple alignments were used to obtain two phylogenies with the maximum likelihood method implemented in PHYML  with HKY as substitution model . The phylogenetic reconstruction was carried out with
a nonparametric bootstrap analysis of 100 replicates for each alignment. TreeDyn program  was used to visualize and edit both phylogenies. Acknowledgements We are grateful to Laura Cervantes and Javier Rivera for their excellent technical CFTRinh-172 clinical trial assistance. We acknowledge Michael F. Dunn for critically reviewing the manuscript. This work was supported by DGAPA-PAPIIT-UNAM grant IN200309-2. Tomás Villaseñor was supported by a Ph. D. scholarship (204725) from CONACYT México during his Ph. D. studies at UNAM, Programa de Doctorado en Ciencias Biomédicas. Electronic supplementary material Additional file 1: Table S1. Rhizobial species list and accession numbers of housekeeping and panCB genes used for phylogenetic analysis. (DOC 42 KB) References 1. Jumas-Bilak E, Michaux-Charachon S, Bourg G, Ramuz M, Allardet-Servent A: Unconventional
genomic organization in the alpha subgroup of the Proteobacteria. J Bacteriol 1998, 180:2749–2755.PubMed 2. MacLean AM, Finan TM, Sadowsky MJ: Genomes of the symbiotic nitrogen-fixing bacteria of legumes. Plant Physiol 2007, 144:615–622.PubMedCrossRef BEZ235 chemical structure 3. Romero D, Brom S: The symbiotic plasmids of the Rhizobiaceae . In Plasmid biology. Edited by: Phillips G, Funnell BE. Washington, D.C: American Society for Microbiology; 2004:271–290. 4. Young JP, Crossman LC, Johnston AW, Thomson NR, Ghazoui ZF, Hull KH, Wexler M, Curson AR, Todd JD, Poole PS, Mauchline TH, East AK, Quail MA, Churcher C, Arrowsmith C, Cherevach I, Chillingworth T, Clarke K, Cronin A, Davis P, Fraser A, Hance Z, Hauser H, Jagels K, Moule S, Mungall K, Norbertczak H, Rabbinowitsch E, Sanders M, Simmonds M, Whitehead
S, Parkhill J: The genome of Rhizobium leguminosarum has recognizable core and accessory components. Genome Biol 2006, 7:R34.PubMedCrossRef 5. Crossman LC, Castillo-Ramírez S, McAnnula C, Lozano L, Vernikos GS, Acosta JL, Ghazoui ZF, Hernández-González I, Meakin G, Walker AW, Hynes MF, Molecular motor Young JPW, Downie JA, Romero D, Johnston AWB, Dávila G, Parkhill J, González V: A common genomic find more framework for a diverse assembly of plasmids in the symbiotic nitrogen fixing bacteria. PLoS ONE 2007, 3:e2567.CrossRef 6. González V, Santamaria RI, Bustos P, Hernández-González I, Medrano-Soto A, Moreno-Hagelsieb G, Janga SC, Ramírez MA, Jimenez-Jacinto V, Collado-Vides J, Dávila G: The partitioned Rhizobium etli genome: genetic and metabolic redundancy in seven interacting replicons. Proc Natl Acad Sci USA 2006, 103:3834–3839.PubMedCrossRef 7. Bittner AN, Foltz A, Oke V: Only one of five groEL genes is required for viability and successful symbiosis in Sinorhizobium meliloti . J Bacteriol 2007, 189:1884–1889.PubMedCrossRef 8.