Open AccessMultilocus Sequence-Based Analysis Delineates a Clonal Population of Agrobacterium (Rhizobium) radiobacter (Agrobacterium tumefaciens) of Human Origin
Author(s) -
Fabien Aujoulat,
Estelle JumasBilak,
Agnès Masnou,
Fanny Sallé,
Denis Faure,
Christine Segonds,
Hélène Marchandin,
Corinne Teyssier
Publication year - 2011
Publication title -
journal of bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.652
H-Index - 246
eISSN - 1067-8832
pISSN - 0021-9193
DOI - 10.1128/jb.00107-11
Subject(s) - biology , agrobacterium , agrobacterium tumefaciens , population , genetics , rhizobiaceae , multilocus sequence typing , rpob , housekeeping gene , ti plasmid , transformation (genetics) , gene , genotype , bacteria , 16s ribosomal rna , gene expression , demography , symbiosis , sociology
The genusAgrobacterium includes plant-associated bacteria and opportunistic human pathogens. Taxonomy and nomenclature within the genus remain controversial. In particular, isolates of human origin were all affiliated with the speciesAgrobacterium (Rhizobium )radiobacter , while phytopathogenic strains were designated under the synonym denominationAgrobacterium tumefaciens . In order to study the relative distribution ofAgrobacterium strains according to their origins, we performed a multilocus sequence-based analysis (MLSA) on a large collection of 89 clinical and environmental strains from various origins. We proposed an MLSA scheme based on the partial sequence of 7 housekeeping genes (atpD ,zwf ,trpE ,groEL ,dnaK ,glnA , andrpoB ) present on the circular chromosome ofA. tumefaciens C58. Multilocus phylogeny revealed that 88% of the clinical strains belong to genovar A7, which formed a homogeneous population with linkage disequilibrium, suggesting a low rate of recombination. Comparison of genomic fingerprints obtained by pulsed-field gel electrophoresis (PFGE) showed that the strains of genovar A7 were epidemiologically unrelated. We present genetic evidence that genovar A7 may constitute a human-associated population distinct from the environmental population. Also, phenotypic characteristics, such as culture at 42°C, agree with this statement. This human-associated population might represent a potential novel species in the genusAgrobacterium .