Phylogenetic diversity of bacterial strains from root nodules of legumes grown wild in Egypt

A total of 38 bacterial strains were isolated from root nodules of Lotus, Vicia, Trifolium, Lathyrus, Astragalus, and Hippocrepis plants grown-wild at different geographical locations in Egypt. Analysis of the almost complete sequence of the 16S rRNA gene from the bacterial strains showed that seventeen of them isolated from all the six plant species were members of the genus Rhizobium, six from Lotus, Vicia and Hippocrepis were Ensifer, and the remaining six strains from Lotus and Vicia were Neorhizobium. Sequencing of the symbiotic nodC gene from eight selected rhizobial strains confirmed their affiliation with rhizobial species. These results suggest the existence of high rhizobial diversity in wild-grown Egyptian legumes. Nodules from Lotus, Trifolium, and Astragalus also contained bacterial species of the genera Achromobacter, Ancylobacter, Bacillus, Cronobacter, Curtobacterium, Flavobacterium, Paenibacillus and Pseudomonas. These results provide information about the diversity of rhizobia associated with wild-grown legumes in Egypt, and enlarged the rhizobial spectrum of Lotus, Vicia, Trifolium, Lathyrus, Hippocrepis and Astragalus, which supported to the idea that rhizobial promiscuity could be an adaption strategy to diverse environments.N.H. El Batanony thanks the Egyptian Ministry of Higher Education and Scientific Research (MoHESR) for funding her stay in the Department of Microbiology and Symbiotic Systems at Estación Experimental del Zaidín, CSIC, in Granada, Spain. The study was supported by the ERDF-cofinanced grant RNM-4746 from Consejería de Economía, Innovación y Ciencia (Junta de Andalucía, Spain)