Morphological, Biochemical and Molecular Characterization of Rhizobia from Halophytes of Khewra Salt Range and Attock

Present investigation was aimed to isolate and characterize plant growth promoting rhizobacteria (Rhizobia) from rhizosphere (EC: 2300 μS/cm; pH: 8.6) of four halophytes: Sonchus arvensis L., (sow thistle), Solanum surratense Burm. F., (yellow berried night shade), Lactuca dissecta D. Don., (wild lettuce) and Chrysopogon aucheri (Boiss.) Stapf (golden beared grass) collected from Khewra Salt Range and compared with Rhizobium isolate from Solanum surratense Burm. F. of arid soil (EC: 210 μS/cm; pH: 7.9) of Attock (treated as control). The isolates were identified and characterized on the basis of colony morphology and biochemical traits viz gram staining, catalase and oxidase tests and carbon and nitrogen source utilization pattern. The survival efficiency of isolates was measured in culture (colony forming unit / g soil). The genetic diversity among the isolates assessed by RAPD-DNA finger printing and PCR was done for the presence of 16S-rRNA gene. On the basis of carbon / nitrogen source utilization patterns, Rhizobium isolates placed in five different groups and were designated as Rkh1, Rkh2, Rkh3, Rkh4 and Rak5 but RAPD tests categorized the isolates into two clusters. The RAPD results were further analyzed by MVSP software; similarity matrix was measured and converted into dendrogram using UPGMA clustering method.