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.

Abstract

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.

Ensifer glycinis sp. nov., a rhizobial species associated with species of the genus Glycine

“…To end the debate, the Judicial Commission of the International Committee on Systematics of Prokaryotes made a final decision that Ensifer takes priority over Sinorhizobium and should be used at least in official journals, such as the International Journal of Systematic and Evolutionary Microbiology (Young, 2010). Since then, the names of eight novel species and new combinations have been validly published within the genus Ensifer, including Ensifer garamanticus (Merabet et al, 2010), Ensifer numidicus (Merabet et al, 2010), Ensifer mexicanus (Lloret et al, 2007), Ensifer sojae (Li et al, 2011a), Ensifer americanus (Wang et al, 2013), Ensifer psoraleae (Wang et al, 2013), Ensifer sesbaniae (Wang et al, 2013) and Ensifer morelensis (Wang et al, 2013).…”

Ensifer alkalisoli sp. nov. isolated from root nodules of Sesbania cannabina grown in saline–alkaline soils

“…Ensifer kummerowiae, Ensifer medicae, Ensifer meliloti, Ensifer mexicanus, Ensifer morelense, Ensifer numidicus, Ensifer psoraleae, Ensifer saheli, Ensifer sesbaniae, Ensifer sojae and Ensifer terangae (Casida Jr, 1982;Li et al, 2011;Lloret et al, 2007;Martens et al, 2008;Merabet et al, 2010;Wang et al, 2013;Yan et al, 2016;Young, 2003). In order to clarify the accurate taxonomic position of this novel Ensifer group, we performed the present study to compare it with the defined Ensifer species.…”

Multilocus sequence analysis supports the taxonomic position of Astragalus glycyphyllos symbionts based on DNA–DNA hybridization

“…A year later, Zeigler (2003) found that a smaller number of genes, or even a single, carefully selected core gene, can equal or even surpass the precision of DNA-DNA reassociation for the quantification of genome relatedness and assigning related bacteria to the correct species. The taxonomic potential of the MLSA technique, confirmed by DNA-DNA relatedness, has allowed the assignment of many nodule bacteria into species (Martens et al, 2008;Merabet et al, 2010;Rincó n-Rosales et al, 2009;Vinuesa et al, 2005). The MLSA technique has also been applied for rapid and reliable species identification in other bacterial genera, e.g.…”