Salt-tolerant rhizobia isolated from a Tunisian oasis that are highly effective for symbiotic N-2-fixation with Phaseolus vulgaris constitute a novel biovar (bv. mediterranense) of Sinorhizobium meliloti - Université de Bourgogne Accéder directement au contenu
Article Dans Une Revue Archives of Microbiology Année : 2007

Salt-tolerant rhizobia isolated from a Tunisian oasis that are highly effective for symbiotic N-2-fixation with Phaseolus vulgaris constitute a novel biovar (bv. mediterranense) of Sinorhizobium meliloti

Résumé

Nodulation of common bean was explored in six oases in the south of Tunisia. Nineteen isolates were characterized by PCR-RFLP of 16S rDNA. Three species of rhizobia were identified, Rhizobium etli, Rhizobium gallicum and Sinorhizobium meliloti. The diversity of the symbiotic genes was then assessed by PCR-RFLP of nodC and nifH genes. The majority of the symbiotic genotypes were conserved between oases and other soils of the north of the country. Sinorhizobia isolated from bean were then compared with isolates from Medicago truncatula plants grown in the oases soils. All the nodC types except for nodC type p that was specific to common bean isolates were shared by both hosts. The four isolates with nodC type p induced N-2-fixing effective nodules on common bean but did not nodulate M. truncatula and Medicago sativa. The phylogenetic analysis of nifH and nodC genes showed that these isolates carry symbiotic genes different from those previously characterized among Medicago and bean symbionts, but closely related to those of S. fredii Spanish and Tunisian isolates effective in symbiosis with common bean but unable to nodulate soybean. The creation of a novel biovar shared by S. meliloti and S. fredii, bv. mediterranense, was proposed

Dates et versions

hal-02667597 , version 1 (31-05-2020)

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Bacem Mnasri, Moncet Mrabet, Gisele Laguerre, Mohamed Elarbi Aouani, Ridha Mhamdi. Salt-tolerant rhizobia isolated from a Tunisian oasis that are highly effective for symbiotic N-2-fixation with Phaseolus vulgaris constitute a novel biovar (bv. mediterranense) of Sinorhizobium meliloti. Archives of Microbiology, 2007, 187 (1), pp.79-85. ⟨10.1007/s00203-006-0173-x⟩. ⟨hal-02667597⟩
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