Phenotypic and genotypic characterization of root nodules rhizobia of Medicago littoralis Rhode and Melilotus indicus (L.) All. growing in the Oasis of Touggourt, Oued Righ Valley, in the Algerian Sahara

Forty rhizobial strains were isolated from root nodules of Medicago littoralis Rhode and Melilotus indicus (L.) harvested from the sandy soils of Touggourt’s oases in the Oued Righ Valley, Algerian Sahara. The isolates were studied for their cultural, biochemical and symbiotic effectiveness. All of them were fast-growing bacteria; utilized a wide range of carbon sources, produced abundant extracellular polysaccharides, tolerated high concentrations of NaCl (up to 2.5 %), grew at temperatures between 28 and 45 °C and at pH values between 4.5 and 9. The isolates were sensitive to the antibiotics kanamycin, tetracycline and rifampicin but showed resistance to neomycin and erythromycin. All the…