DIVERSITY OF BACTERIA ASSOCIATED WITH ROOT NODULES OF HEDYSARUM PALLIDUM DESF. GROWING IN DIFFERENT REGIONS OF ALGERIALEYLA BOUKAOUS, RAOUDHA FERJANI, HANANE MELLAL, WAJDI MIMOUNI2, RADJA TIR, MERIEM GACI, MARWA CHERNI, ANDREA SQUARTINI, HADDA IMENE OUZARI AND YACINE BENHIZIA
This work deals with the study of the bacterial diversity associated with the wild legume Hedysarum pallidum nodules collected from six different sites of Algeria along a geobioclimatic level transect. A total of eighty-one bacterial isolates were retrieved from harvested plants nodules. Isolates were subjected to preliminary sorting through internal transcribed spacer 16S-23S rRNA amplification, which allowed the distinction of 20 different polymorphic haplotypes. Thirty-two representative isolates were subjected to species identification using partial 16S rRNA gene sequencing. The identified strains were affiliated to Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria and Firmicutes with an uneven distribution between the different sites indicating an important bacterial diversity. The phenotypic characterization carried out illustrated the diversity of the isolates. Principal Component Analysis (PCA) of soil parameters showed a differentiation between soil samples. Denaturing gradient gel electrophoresis analysis (DGGE), highlighted the presence of a band across all investigated samples that showed 100% nucleotide identity to Mesorhizobium camelthorni. Such uncultured taxon is envisaged as the responsible of nodule induction in Hedysarum pallidum but the role and possible contribution to the symbiosis exerted by culturable bacteria are discussed.