Characterization of tropical tree rhizobia and description of Mesorhizobium plurifarium sp. nov.

Laboratoire de Microbiologie des Sols, ORSTOM, Dakar, Senegal, West Africa.
International journal of systematic bacteriology (Impact Factor: 2.27). 04/1998; 48 Pt 2:369-82. DOI: 10.1099/00207713-48-2-369
Source: PubMed

ABSTRACT A collection of strains isolated from root nodules of Acacia species in Senegal was analysed previously by electrophoresis of total cell protein, auxanographic tests, rRNA-DNA hydridization, 16S rRNA gene sequencing, DNA base composition and DNA-DNA hybridization [de Lajudie, P., Willems, A., Pot, B. & 7 other authors (1994). Int J Syst Bacteriol 44, 715-733]. Strains from Acacia were shown to belong to two groups, Sinorhizobium terangae, and a so-called gel electrophoretic cluster U, which also included some reference strains from Brazil. Further taxonomic characterization of this group using the same techniques plus repetitive extragenic palindromic-PCR and nodulation tests is presented in this paper. Reference strains from Sudan and a number of new rhizobia isolated from nodules of Acacia senegal, Acacia tortilis subsp. raddiana and Prosopis juliflora in Senegal were included. As a result of this polyphasic approach, the creation of a new species, Mesorhizobium plurifarium, is proposed for a genotypically and phenotypically distinct group corresponding to the former cluster U and containing strains isolated from Acacia, Leucaena, Prosopis and Chamaecrista in West Africa (Senegal), East Africa (Sudan) and South America (Brazil). The type strain of Mesorhizobium plurifarium ORS 1032 has been deposited in the LMG collection as LMG 11892.

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    ABSTRACT: Eighteen Mesorhizobium strains, obtained from root nodules of woody legumes growing in Ethiopia, were previously shown by multilocus sequence analysis of five housekeeping genes to form three novel genospecies (Degefu et al., 2011). In the present study, the phylogenetic relationship between representative strains of these three genospecies and the type strains of their closest phylogenetic neighbors Mesorhizobium plurifarium, Mesorhizobium amorphae, Mesorhizobium septentrionale and Mesorhizobium huakuii was further evaluated using a polyphasic taxonomic approach. In line with our earlier MLSA of other house-keeping genes, the phylogenetic trees derived from the atpD and glnII genes grouped the test strains into three well-supported, distinct lineages that exclude all defined Mesorhizobium species. The DNA-DNA relatedness between the representative strains of genospecies I-III and the type strains of their closest phylogenetic neighbors was low (≤ 59 %). They differed from each other and from their closest phylogenetic neighbors by presence/absence of several fatty acids, or by large differences in the relative amount of particular fatty acids. While showing distinctive features with one or more references, they were generally able to utilize a wide range of substrates as sole carbon and nitrogen sources. The strains belonging to genospecies I, II and III therefore represent novel species for which we propose the names M. shonense sp. nov., M. hawassense sp. nov. and M. abyssinicae sp. nov. The isolates AC39aT (=LMG 26966T = HAMBI 3295T), AC99bT (=LMG 26968T = HAMBI 3301T) and AC98cT (=LMG 26987T = HAMBI 3306T) are proposed as type strains for the respective novel species.
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    Microbiological Research 09/2013; · 1.99 Impact Factor

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