title: Symbiotic characterization and diversity of rhizobia associated with native and introduced acacias in arid and semi-arid regions in Algeria.
abstract: The diversity of rhizobia associated with introduced and native Acacia species in Algeria was investigated from soil samples collected across seven districts distributed in arid and semi-arid zones. The in vitro tolerances of rhizobial strains to NaCl and high temperature in pure culture varied greatly regardless of their geographical and host plant origins but were not correlated with the corresponding edaphoclimatic characteristics of the sampling sites, as clearly demonstrated by principal component analysis. Based on 16S rRNA gene sequence comparisons, the 48 new strains isolated were ranked into 10 phylogenetic groups representing five bacterial genera, namely, Ensifer, Mesorhizobium, Rhizobium, Bradyrhizobium, and Ochrobactrum. Acacia saligna, an introduced species, appeared as the most promiscuous host because it was efficiently nodulated with the widest diversity of rhizobia taxa including both fast-growing ones, Rhizobium, Ensifer, and Mesorhizobium, and slow-growing Bradyrhizobium. The five other Acacia species studied were associated with fast-growing bacterial taxa exclusively. No difference in efficiency was found between bacterial taxa isolated from a given Acacia species. The tolerances of strains to salinity and temperature remains to be tested in symbiosis with their host plants to select the most adapted Acacia sp.-LNB taxa associations for further revegetation programs.
authors.affiliation: Laboratoire de Biotechnologie des Rhizobiums et Amélioration des Plantes, Département de Biotechnologie, Université d'Oran, Es Senia, Algeria.
authors.forename: Zineb Faiza
authors.initials: ZF
authors.lastname: Boukhatem
authors.forename: Odile
authors.initials: O
authors.lastname: Domergue
authors.forename: Abdelkader
authors.initials: A
authors.lastname: Bekki
authors.forename: Chahinez
authors.initials: C
authors.lastname: Merabet
authors.forename: Sonia
authors.initials: S
authors.lastname: Sekkour
authors.forename: Fatima
authors.initials: F
authors.lastname: Bouazza
authors.forename: Robin
authors.initials: R
authors.lastname: Duponnois
authors.forename: Philippe
authors.initials: P
authors.lastname: de Lajudie
authors.forename: Antoine
authors.initials: A
authors.lastname: Galiana
mesh_terms: D000045:Acacia / Q000382:microbiology*; D000462:Algeria; D020369:Bradyrhizobium / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D004269:DNA, Bacterial / Q000235:genetics; D003889:Desert Climate; D006358:Hot Temperature; D059128:Mesorhizobium / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D008969:Molecular Sequence Data; D042041:Ochrobactrum / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012231:Rhizobium / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D054712:Salinity; D012988:Soil Microbiology; D013559:Symbiosis
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S