Isolation and identification of rhizobial strains from faba bean nodules.

To maximize of faba bean production in the new reclaimed land in Egypt need to isolate and select of effective rhizobial strains. Thirty rhizobial isolates were collected from the healthy root nodule of faba bean (Vicia faba) grow in different geographic locations and soil properties in Egypt. Morphological studies, nodulation, salinity tolerance, as well as 16S rDNA partial sequence were used for identification and characterization the obtained rhizobial isolates. All tested isolates were short rod, Gram negative and most of them were opaque and high viscosity. According to nodulation, the promising isolates were determined. The most promising isolates tolerated the high NaCl concentration up to 3.5 and 4%. Moreover the two isolates are 2 is and Nob3 had a positive growth at 4.5% NaCl concentration (10⁷Rhizobial cell per ml.). Data showed that both Is 2 and Nob 3 isolates were the best isolates where they gave the highest number of nodules and growth characteristics of the two faba bean varieties. The 16S rDNA sequencing results revealed that the nearest bacterial species to our isolate M4 was Rhizobium sp. (KF111868) 94% identity while, M6 isolate was 99% identical to Rhizobium rubi (BBJU0100046). The sequence was submitted to NCBI website with accession number Gen Bank: KX639721 and KX639722 respectively.