Phenotypic and genotypic diversity of Genista saharae microsymbionts from the infra-arid region of Tunisia

Mahdhi, Mosbah; N’Zoué, Angèle; Guèye, Fatou; Merabet, Chahinez; Lajudie, Philippe de; Mars, Mohamed

doi:10.1111/j.1472-765x.2007.02233.x

Cited by 33 publications

(20 citation statements)

References 16 publications

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“…These results corroborate our earlier reports on the root nodule bacteria isolated from wild legumes in Tunisia (Mahdhi et al, 2007;Rejili et al, 2009;Fterich et al, 2011). Similarly, Guerrouj et al (2013) reported that rhizobial strains associated to A. glombiformis are tolerant to 342 mM NaCl and 40°C in Eastern Morocco.…”

Section: Rhizobium Gallicum R602sp T (U86343)supporting

confidence: 92%

Characterization of Rhizobial Bacteria Nodulating Astragalus corrugatus and Hippocrepis areolata in Tunisian Arid Soils

Mahdhi

Houidheg

Mahmoudi

et al. 2016

Polish Journal of Microbiology

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A b s t r a c tFifty seven bacterial isolates from root nodules of two spontaneous legumes (Astragalus corrugatus and Hippocrepis areolata) growing in the arid areas of Tunisia were characterized by phenotypic features, 16S rDNA PCR-RFLP and 16S rRNA gene sequencing. Phenotypically, our results indicate that A. corrugatus and H. areolata isolates showed heterogenic responses to the different phenotypic features. All isolates were acid producers, fast growers and all of them used different compounds as sole carbon and nitrogen source. The majority of isolate grew at pHs between 6 and 9, at temperatures up to 40°C and tolerated 3% NaCl concentrations. Phylogenetically, the new isolates were affiliated to four genera Sinorhizobium, Rhizobium, Mesorhizobium and Agrobacterium. About 73% of the isolates were species within the genera Sinorhizobium and Rhizobium. The isolates which failed to nodulate their host plants of origin were associated to Agrobacterium genus (three isolates). 3 332 Guerrouj et al., 2013;Gnat et al., 2014). Surprisingly, Muresu et al. (2008) reported that strains isolated from Hippocrepis unisiliquosa are identified as members of the genus Bacillus or as uncultured bacteria.At Tunisia, Astragalus and Hippocrepis nitrogenfixing symbiotic associations are poorly documented (Zakhia et al., 2004;Mantelin et al., 2006). Previous research's reported that rhizobia associated to Astragalus glombiformis, Astragalus armatus, Astragalus corrugatus and Astragalus algerianus were assigned to the genus of Rhizobium and Phyllobacterium, and only one isolate from nodules Hippocrepis areolata was affiliated to the genus Sinorhizobium (Zakhia et al., 2004).Considering the potential value of the Astragalus and Hippocrepis species in the arid regions of Tunisia and the little information available about the diversity of their root nodulating bacteria, the present paper aim to determine the taxonomic diversity of 57 bacterial collection isolated from root nodules of A. corrugatus and H. areolata by using polyphasic approach including phenotypic and PCR-RFLP analysis and 16S rRNA gene sequencing. Experimental Materials and MethodsBacterial isolation and growth conditions. Fifty seven isolates and six reference strains (Table I) representing different rhizobial species belonging to Rhizobium, Sinorhizobium and Mesorhizobium were used in this study. Rhizobial bacteria were isolated from naturally occurring root nodules collected in four arid soils of Tunisia (Table I). For rhizobia isolation, healthy nodules dissected from roots were surface sterilized with ethanol (70%) and sodium hypochlorite (2%). Then nodules were separately crushed and the nodule juice was streaked on plates of yeast-mannitol agar (YMA) (Vincent, 1970) and incubated at 28°C for the isolation of the rhizobia. The obtained bacterial colonies were purified by being repeatedly streaked on the same medium. Pure isolates were stored with 25% (wt/vol) glycerol at −80°C.Nodulation test. To assess nodulation, seeds were surface-sterilized in 98% sulphuric ...

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Section: Rhizobium Gallicum R602sp T (U86343)supporting

confidence: 92%

Characterization of Rhizobial Bacteria Nodulating Astragalus corrugatus and Hippocrepis areolata in Tunisian Arid Soils

Mahdhi

Houidheg

Mahmoudi

et al. 2016

Polish Journal of Microbiology

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“…All isolates, except HM2, HM3, HM4, HM5 and HM6, induce nodules in their host plant. These five isolates can be considered as opportunistic as already proposed Mahdhi et al 2007Mahdhi et al , 2008. Phenotypically, our study indicates that microsymbionts demonstrated a high heterogeneity of several phenotypic characters.…”

Section: Discussionmentioning

confidence: 79%

Legume-nodulating bacteria (LNB) from three pasture legumes (Vicia sativa, Trigonella maritima and Hedysarum spinosissimum) in Tunisia

et al. 2011

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Sixty-one bacterial isolates were recovered from surface-sterilized root nodules of Vicia sativa, Trigonella maritima and Hedysarum spinosissimum plants growing in two arid Tunisian soils. The natural nodulation resource of these legumes, prospected from the two sites, was investigated. The occurrence of nodulation and the morphology of the nodules were observed. The isolates were examined by phenotypic characterization and 16S rDNA analysis. Among the 61 isolates that were screened, the majority (92%) were fast-growing rhizobia. Twenty-eight strains tolerated high concentration of salt (3% NaCl) and grew at temperatures up to 40°C. PCR restriction fragment length polymorphism (PCR-RFLP) and 16S rRNA gene sequencing revealed that the majority of the isolates belonged to the genera Rhizobium (54%) and Sinorhizobium (42%). Five H. spinosissimum isolates failed to nodulate their host plant, and were affiliated to Pseudomonas and Kocuria genera. This study is the first report that describes bacteria of genus Kocuria occupying root nodules of legumes to the best of our knowledge.

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“…garamanticus, pertaining to Garamante, Garamantian, the country of Garamantes, from which the strains were isolated). Mahdhi et al (2007), share identical 16S rRNA gene sequence with the type strain of E. garamanticus. They may be thus be considered as members of this species.…”

Section: Discussionmentioning

confidence: 97%

Multilocus sequence analysis of root nodule isolates from Lotus arabicus (Senegal), Lotus creticus, Argyrolobium uniflorum and Medicago sativa (Tunisia) and description of Ensifer numidicus sp. nov. and Ensifer garamanticus sp. nov.

Merabet

Martens

Mahdhi

et al. 2010

International Journal of Systematic and Evolutionary Microbiology

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Nine isolates from Argyrolobium uniflorum, Lotus creticus, Medicago sativa (Tunisia) and Lotus arabicus (Senegal) were analysed by multilocus sequence analysis (MLSA) of five housekeeping genes (recA, atpD, glnA, gltA and thrC), the 16S rRNA gene and the nodulation gene nodA. Analysis of the individual and concatenated gene sequences demonstrated that the nine new strains constituted three stable, well-supported (bootstrap and gene sequence similarity values) monophyletic clusters, A, B and C, all belonging to the branch of the genus Ensifer, regardless of the phylogenetic reconstruction method used (maximum likelihood, maximum-parsimony, neighbour-joining). The three groups were further characterized by API 100 auxanographic tests, host specificity and nodA gene sequence analysis. On the basis of these data, clusters A and C are suggested as representing two novel species within the genus Ensifer, for which the names Ensifer numidicus sp. nov. (type strain ORS 1407T=LMG 24690T=CIP 109850T) and Ensifer garamanticus sp. nov. (type strain ORS 1400T=LMG 24692T=CIP 109916T) are proposed. The cluster B strains were assigned to Ensifer adhaerens genomovar A.

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Phenotypic and genotypic diversity of Genista saharae microsymbionts from the infra-arid region of Tunisia

Cited by 33 publications

References 16 publications

Characterization of Rhizobial Bacteria Nodulating Astragalus corrugatus and Hippocrepis areolata in Tunisian Arid Soils

Characterization of Rhizobial Bacteria Nodulating Astragalus corrugatus and Hippocrepis areolata in Tunisian Arid Soils

Legume-nodulating bacteria (LNB) from three pasture legumes (Vicia sativa, Trigonella maritima and Hedysarum spinosissimum) in Tunisia

Multilocus sequence analysis of root nodule isolates from Lotus arabicus (Senegal), Lotus creticus, Argyrolobium uniflorum and Medicago sativa (Tunisia) and description of Ensifer numidicus sp. nov. and Ensifer garamanticus sp. nov.

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