Taxonomic characterization of Ochrobactrum sp. isolates from soil samples and wheat roots, and description of Ochrobactrum tritici sp. nov. and Ochrobactrum grignonense sp. nov.

Abstract

A large collection of bacterial strains, immunotrapped from soil and from the wheat rhizoplane, was subjected to polyphasic taxonomy by examining various pheno-and genotypic parameters. Strains were grouped on (inter) repetitive extragenic palindromic DNA (REP) PCR profiles at the intraspecies level. Pheno-and genotypic characters were assessed for representatives from 13 different REP groups. Strains of nine REP groups constituting two physiological BIOLOG clusters fell in the coherent DNA-DNA reassociation group of Ochrobactrum anthropi. Strains of two REP groups constituting a separate BIOLOG cluster fell in the coherent DNA-DNA reassociation group of Ochrobactrum intermedium. Additional phenotypic characters differentiating O. anthropi and O. intermedium were found. REP group K strains constituted a different BIOLOG cluster, a separate DNA-DNA reassociation group and a distinct phylogenetic lineage in 16S rDNA homology analysis, indicating that REP group K strains represent a new species. Diagnostic phenotypic characters were found. Closest relatives were Ochrobactrum species. The name Ochrobactrum grignonense sp. nov. is proposed (type strain OgA9a T l LMG 18954 T l DSM 13338 T ). REP group J strains again constituted a different BIOLOG cluster, a separate DNA-DNA reassociation group and showed, as a biological particularity, a strict preference for the rhizoplane as habitat. Diagnostic phenotypic characters were found. This indicated that REP group J strains represent a further new species, although phylogenetic analyses using 16S rDNA homology were not able to separate the cluster of REP group J sequences significantly from 16S rDNA sequences of Ochrobactrum anthropi. The name Ochrobactrum tritici sp. nov. is proposed (type strain SCII24 T l LMG 18957 T l DSM 13340 T ).

Molecular and phenotypic features for identification of the opportunistic pathogens Ochrobactrum spp.

“…On the basis of phenotypic characteristics, the genus Ochrobactrum could be related to the genera Alcaligenes, Achromobacter, or to the members of Pseudomonadaceae. However, molecular taxonomy places Ochrobactrum in the AE-subgroup of proteobacteria, closely related to the genus Brucella (Lebuhn et al, 2000;Velasco et al, 1998). Surprisingly, 16S rDNA-based phylogeny, as well as protein profiling (Velasco et al, 1998) and AFLP analysis (Leal-Klevezas et al, 2005), place O. intermedium strains closer to Brucella spp.…”

“…Since this description, five other species, Ochrobactrum intermedium (Velasco et al, 1998), Ochrobactrum tritici, Ochrobactrum grignonense (Lebuhn et al, 2000), Ochrobactrum gallinifaecis (Kämpfer et al, 2003) and 'Ochrobactrum lupini' (Trujillo et al, 2005) have been characterized, mainly on the basis of 16S rDNA sequencing. They are non-fermentative, strictly aerobic, motile, oxidase-positive and indole-negative, Gramnegative rods.…”

Ochrobactrum haematophilum sp. nov. and Ochrobactrum pseudogrignonense sp. nov., isolated from human clinical specimens

“…*Tests (based on different methods) were also performed in the following studies and gave congruent results: a, Holmes et al (1988) with O. anthropi;b, Velasco et al (1998) with O. intermedium; c, Lebuhn et al (2000) with type strains of all four previously described species. DStrain CCUG 30717 T showed only weakly positive results.…”

“…The genus Ochrobactrum was introduced by Holmes et al (1988) and, at the time of writing, the genus comprises the nine species Ochrobactrum anthropi (Holmes et al, 1988), O. intermedium (Velasco et al, 1998), O. tritici and O. grignonense (Lebuhn et al, 2000), O. gallinifaecis (Kämpfer et al, 2003b), O. lupini (Trujillo et al, 2005), O. oryzae (Tripathi et al, 2006), O. pseudintermedium (ZurdoPiñeiro et al, 2007) and O. cytisi (Teyssier et al, 2007).…”

Isolamento de Gluconacetobacter spp. em diferentes tipos de solos

“…Com o uso da técnica, três isolados foram obtidos das quatro amostras avaliadas, ao passo que, por meio do método tradicional (meio de cultivo semi-sólido sem N), não foi possível o isolamento desta espécie. Lebuhn et al (2000) utilizaram esta técnica modificada -uso de tampão glicina para separação da bactéria acoplada ao soro -e isolaram estirpes de Ochrobactrum sp. de amostras de trigo desenvolvido em diferentes tipos de solo.…”