Isolation And Identification Of Mineral Phosphate-solubilizing Bacteria From Soils & Clone Of The Mineral Phosphate-solubilizing Gene From Enterobacter Cloacae

Phosphate-solubilizing microorganisms(PSM) in soils play an important role in phosphorus cycling, can transform insoluble phosphate into soluble phosphate and improve using of the phosphate fertilizer. Some researches on PSM are taken, the results as followes:In this experiment, 30 strains of phosphate-solubilizing bacteria isolated from the soil of 4 kinds of areas in Beijing, were studied the characters of phosphate-solubilizing along with the other 22 strains of bacteria stored in this lab.Among the strains C-2, C-12 , C-15, CW-1 were identified by Biolog Automation System,the results were: C-2 as Burkolderia caryophylli,C-12 as Enterobacter cloacae,C-15 as Pseudomonas aeruginsoa,however CW-1 were not given species identification in the database of bacterium. Physiological and biochemical tests of the strain C-12 were studied and 16S rDNA sequences were analyzed. Our results showed the C-12 was Enterobacter cloacae.The C-12 was mutated by Tn5 transponson, however no mutant without phosphate-solubilizing ability was obtained from 20,000 exconjugants by different methods. Maybe the phosphate-dissolving character was controlled by more complex gene and new methods needed were applied to measure the phosphate-dissolving ability of the mutants. Designing primers based on sequences of pqqE gene in others bacteria and getting one product about 582bp by PCR show 85% similarity with the gene cloned from other bacteria.The product was labeled by DIG as probe and then found the only signal band located in the genomic DNA in Southern blotting experiment.