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ABSTRACT: Five Gram-negative, rod-shaped, non-spore-forming bacteria were isolated from galls on different plant species in Hungary: strain 39/7(T) from Prunus cerasifera Myrobalan, strain 0 from grapevine var. Ezerjó, strain 7/1 from raspberry var. Findus and in Poland, strain C3.4.1 from Colt rootstock (Prunus avium × Prunus pseudocerasus) and strain CP17.2.2 from Prunus avium. Only one of these isolates, strain 0, is able to cause crown gall on different plant species. On the basis of 16S rRNA gene sequence similarity, the strains cluster together and belong to the genus Rhizobium and their closest relative is Rhizobium radiobacter (99.1%). Phylogenetic analysis of the novel strains using housekeeping genes atpD, glnA, gyrB, recA and rpoB revealed their distinct position separate from other known Rhizobium species and confirmed their relation to Rhizobium radiobacter. The major cellular fatty acids are 18:1 w7c, 16:0, 16:0 3OH, summed feature 2 (comprising 12:0 aldehyde, 16:1 iso I and/or 14:0 3OH) and summed feature 3 (comprising 16:1 w7c and/or 15 iso 2OH). DNA-DNA hybridization of strain 39/7(T) with the type strain of R. radiobacter LMG 140(T) revealed 45% DNA-DNA hybridization. Phenotypic and physiological properties differentiate the novel isolates from other closely related species. On the basis of the results obtained, the five isolates are considered to represent a novel species of the genus Rhizobium, for which the name Rhizobium nepotum sp. nov. (type strain 39/7(T)=LMG 26435(T)=CFBP 7436(T)) is proposed.
Systematic and Applied Microbiology 03/2012; 35(4):215-20. · 3.37 Impact Factor
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ABSTRACT: Gram-negative, rod-shaped bacteria were isolated from Robinia pseudoacacia root nodules. On the basis of the 16S rRNA gene phylogeny, they are closely related to Bradyrhizobium, Rhodopseudomonas and Nitrobacter species (97% sequence similarity), belonging to the class Alphaproteobacteria and family Bradyrhizobiaceae. The results of physiological and biochemical tests together with sequence analysis of housekeeping genes (atpD, dnaK, gyrB, recA and rpoB) allowed differentiation of this group from other validly published Bradyrhizobiaceae genera. NodA, nodC and nifH genes could not be amplified. On the basis of genotypic and phenotypic data, these organisms represent a novel genus and species for which the name Tardiphaga robiniae gen. nov., sp. nov. (LMG 26467(T)=CCUG 61473(T)), is proposed.
Systematic and Applied Microbiology 03/2012; 35(4):205-14. · 3.37 Impact Factor
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ABSTRACT: Strains of Gram-negative, rod-shaped, non-spore-forming bacteria were isolated from nitrogen-fixing nodules of the native legumes Listia angolensis (from Zambia) and Lupinus texensis (from Texas, USA). Phylogenetic analysis of the 16S rRNA gene showed that the novel strains belong to the genus Microvirga, with 96.1 % or greater sequence similarity with type strains of this genus. The closest relative of the representative strains Lut6T and WSM3557T was M. flocculans TFBT, with 97.6-98.0 % similarity, while WSM3693T was most closely related to M. aerilata 5420S-16T, with 98.8 % similarity. Analysis of the concatenated sequences of four housekeeping gene loci (dnaK, gyrB, recA, rpoB) and cellular fatty acid profiles confirmed the placement of Lut6T, WSM3557T and WSM3693T within Microvirga. DNA:DNA relatedness values and physiological and biochemical tests allowed genotypic and phenotypic differentiation of Lut6T, WSM3557T and WSM3693T from each other and from other validly published Microvirga species. The nodA sequence of Lut6T was placed in a clade that contained strains of Rhizobium, Mesorhizobium and Sinorhizobium, while the 100 % identical nodA sequences of WSM3557T and WSM3693T clustered with Bradyrhizobium, Burkholderia and Methylobacterium strains. Concatenated sequences for nifD and nifH show that Lut6T, WSM3557T and WSM3693T were most closely related to Rhizobium etli CFN42T nifDH. On the basis of genotypic, phenotypic and DNA relatedness data, three novel species of Microvirga are proposed: Microvirga lupini (Lut6T = LMG26460T, = HAMBI 3236) Microvirga lotononidis (WSM3557T = LMG26455T, = HAMBI 3237) and Microvirga zambiensis (WSM3693T = LMG26454T, = HAMBI 3238).
INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY 12/2011; · 2.11 Impact Factor
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ABSTRACT: Gram-negative, rod-shaped bacteria were isolated from root nodules of Lupinus polyphyllus, Lathyrus latifolius and Robinia pseudoacacia. Based on the 16S rRNA gene phylogeny, they were closely related to Bosea species (100-97 % similarity), belonging to the class Alphaproteobacteria, family Bradyrhizobiaceae. The closest relatives of LMG 26383(T), LMG 26379(T) and LMG 26381(T) were respectively the type strains of Bosea thiooxidans (99.6 %), B. eneae (98.3 %) and B. minatitlanensis (99.0 %). Chemotaxonomic data, including major fatty acid profiles, supported the assignment of our strains to the genus Bosea. Analysis of the concatenated sequences of five housekeeping genes (atpD, dnaK, gyrB, recA and rpoB) and the results of DNA-DNA hybridizations and physiological and biochemical tests allowed genotypic and phenotypic differentiation of our strains from each other and from the five Bosea species with validly published names. No nodA or nodC genes could be amplified, while nifH PCR gave non-specific products. On the basis of genotypic and phenotypic data, three novel species, Bosea lupini sp. nov. (type strain LMG 26383(T) = CCUG 61248(T) = R-45681(T)), Bosea lathyri sp. nov. (type strain LMG 26379(T) = CCUG 61247(T) = R-46060(T)) and Bosea robiniae sp. nov. (type strain LMG 26381(T) = CCUG 61249(T) = R-46070(T)), are proposed.
INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY 12/2011; 62(Pt 10):2505-10. · 2.11 Impact Factor
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ABSTRACT: We investigated the diversity of rhizobia isolated from differentindigenouslegumes in Flanders (Belgium). A total of 3810 bacterial strains were analysed originating from 43 plant species. Based on rep-PCR clustering, 16S rRNA gene and recA gene sequence analysis, these isolates belonged to Bradyrhizobium, Ensifer (Sinorhizobium), Mesorhizobium and Rhizobium. Of the genera encountered, Rhizobium was the most abundant (62%) and especially the species Rhizobium leguminosarum, followed by Ensifer (19%), Bradyrhizobium (14%) and finally Mesorhizobium (5%). For two rep-clusters only low similarity values with other genera were found for both the 16S rRNA and recA genes, suggesting that these may represent a new genus with close relationship to Rhodopseudomonas and Bradyrhizobium. Primers for the symbiotic genes nodC and nifH were optimized and a phylogenetic sequence analysis revealed the presence of different symbiovars including genistearum, glycinearum, loti, meliloti, officinalis, trifolii and viciae. Moreover, three new nodC types were assigned to strains originating from Ononis, Robinia and Wisteria, respectively. Discriminant and MANOVA analysis confirmed the correlation of symbiosis genes with certain bacterial genera and less with the host plant. Multiple symbiovars can be present within the same host plant, suggesting the promiscuity of these plants. Moreover, the ecoregion did not contribute to the separation of the bacterial endosymbionts. Our results reveal a large diversity of rhizobiaassociated with indigenouslegumes in Flanders. Most of the legumes harboured more than one rhizobial endosymbiont in their root nodules indicating the importance of including sufficient isolates per plant in diversity studies.
Soil Biology and Biochemistry 12/2011; 43(2):2384-2396. · 3.50 Impact Factor
