ISOLATION OF SALT TOLERANT RHIZOBACTERIA WITH PHOSPHATE SOLUBILIZATION AND NITROGEN FIXATION TRAITS FROM SOME DIFFERENT FIELDS IN KERMAN, IRAN

Background and Aim:Plant Growth Promoting Rhizobacteria (PGPR) are highly diverse and this research in the subject of Microbial biotechnology in agriculture focus on the saline resistant indigenous bacteria with beneficial effects on plant growth because native rhizobacteria in our arid and semi-arid regions adapted to abiotic stresses.Methods:Soil samples were collected from rhizosphere of plants of fields in Kerman. 5 grams of rhizosphere soil samples were suspended to 45 ml sterile saline. Following serial dilution technique and using Luria agar, different colonies were obtained. The ability of isolates to fix atmospheric nitrogen was confirmed by growth of spot inoculated isolates on nitrogen free media as Burk, Jensen and Ashby’s media. 10 μl aliquot of each suspension with 1×107 CFU/ml was spot inoculated on sperber agar. A clear zone around each spot was considered positive evidence of phosphate solubilization. Luria broth tubes were prepared in different NaCl concentrations as 0.5 to 9.0%. Inoculated tubes were incubated at 30oC for 7 days and growth was measured by O.D. at 660 nm.Results:Out of 20 isolates, 5 resistant rhizobacteria to 9% NaCl were selected. They showed considerable phosphate solubilization as (SE: 3229, 3216, 3219, 3223 and 3226). Their abilities to grow on nitrogen free media also revealed nitrogen fixation trait.Conclusion:selected rhizobacteria showed very promising results on phosphate solubilization, nitrogen fixation and salt resistance and they have very good potential to be used in further experiments for molecular identification and may be biofertilizer construction.

کلیدواژه ها:

Phosphate solubilization ، Nitrogen fixation ، NaCl resistance ، Rhizobacteria ، PGPR