title: The celC gene, a new phylogenetic marker useful for taxonomic studies in Rhizobium.
abstract: The celC gene codifies for a cellulase that fulfils a very significant role in the infection process of clover by Rhizobium leguminosarum. This gene is located in the celABC operon present in the chromosome of strains representing R. leguminosarum, Rhizobium etli and Rhizobium radiobacter whose genomes have been completely sequenced. Nevertheless, the existence of this gene in other species of the genus Rhizobium had not been investigated to date. In this study, the celC gene was analysed for the first time in several species of this genus isolated from legume nodules and plant tumours, in order to compare the celC phylogeny to those of other chromosomal and plasmidic genes. The results obtained showed that phylogenies of celC and chromosomal genes, such as rrs, recA and atpD, were completely congruent, whereas no relation was found with symbiotic or virulence genes. Therefore, the suitability and usefulness of the celC gene to differentiate species of the genus Rhizobium, especially those with closely related rrs genes, was highlighted. Consequently, the taxonomic status of several strains of the genus Rhizobium with completely sequenced genomes is also discussed.
authors.affiliation: Departamento de Microbiología y Genética, Universidad de Salamanca, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Robledo
authors.forename: Encarna
authors.initials: E
authors.lastname: Velázquez
authors.forename: Martha Helena
authors.initials: MH
authors.lastname: Ramírez-Bahena
authors.forename: Paula
authors.initials: P
authors.lastname: García-Fraile
authors.forename: Ana
authors.initials: A
authors.lastname: Pérez-Alonso
authors.forename: Raúl
authors.initials: R
authors.lastname: Rivas
authors.forename: Eustoquio
authors.initials: E
authors.lastname: Martínez-Molina
authors.forename: Pedro F
authors.initials: PF
authors.lastname: Mateos
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D004269:DNA, Bacterial / Q000235:genetics; D007887:Fabaceae / Q000382:microbiology; D010802:Phylogeny; D012231:Rhizobium / Q000145:classification / Q000201:enzymology / Q000235:genetics*; D017422:Sequence Analysis, DNA; D013559:Symbiosis; D029921:Trifolium / Q000382:microbiology; D014774:Virulence / Q000235:genetics; D001617:beta-Glucosidase / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; C083712:celC protein, bacteria; D001617:beta-Glucosidase