Phenotypical and genotypical characteristics of root-nodulating bacteria isolated from annual Medicago spp. in Soummam Valley (Algeria)

Abstract

In the framework of agro-pastoral system management using local annual medics coupled with their native root-nodulating bacteria to extend pasture zones, increase forage yields and improve ovine and bovine breeding in Algeria, we investigated diversity of rhizobia from annual Medicago spp. (Medicago arabica, Medicago polymorpha, Medicago minima and Medicago orbicularis).Ten nodulating-isolates were characterized by morphological, cultural, physiological and biochemical features, SDS-PAGE analysis and PCR-RFLP of 16S rDNA. The results show some degree of genetic diversity among the isolates; three can be affiliated to Sinorhizobium meliloti, one to Rhizobium galegae and six were separate.Local annual medics would have a high degree of specificity in their symbiotic interaction. Furthermore, our results support the presence of Rh. galegae in the Mediterranean region.This work is a preliminary step towards selection of efficient symbiotic Medicago-rhizobia to develop inoculants for management of agro-pastoral systems using local annual medics in Algeria.