Abstract
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.