Research On Organophosphate-dissolving Bacteria From The Rizosphere Soil Of Chinese Pine

Phosphorus is an essential mineral element for the growth and development of plants. Although the total phosphorus content is high, the available phosphorus content is very low in farmland soil. How to solve this problem that the deficiency of phosphorus in the soil? As we all known, it is feasible to apply fertilizer to improve soil phosphorus content, but this is easy to cause environmental pollution even the utilization is not high. Using the-solubilizing roots bacterium of plants and biological systems related to phosphorus cycle to regulate the use of phosphorus in roots, is one of the most effective ways. There are many types of solubilizing microorganisms, including bacteria, fungi and actinomycetes. Bacteria are divided into organic phosphorus and inorganic phosphorus. Organophosphate-dissolving bacteria is capable to convert the phosphorus which is difficult to be absorded by plants into available shape, these bacteria have potential value in application. This study involves the isolation, identification and solubilizing properties of organophosphate-dissolving bacteria in Chinese pine roots soil from Qingshuihe County. It is safe to make conclusions as following:(1) In plate culture, four strains with stronger solubilizing ability were obtained based on the determination of solubilizing circle, which are named YP-l,YP-3, YP-4and YP-7. The order of organophosphate-dissolving ability is YP-3> YP-4> YP-7> YP-1, the ratio of D/d are3.15,2.61,2.27and1.56respectively. In liquid culture, YP-1has the strongest ability in solubilizing, and YP-4in the second. Solubilizing capacity of this two strains are24.42±0.52μg/mL and23.47±0.38μg/mL.(2) The identifications depended on morphological, physiological, biochemical and molecular biology of strains YP-1, YP-3, YP-4and YP-7are Pseudomonas, Stenotrophomonas sp,seudomonas fluorescens and Lysobacter sp respectively.(3) For organophosphate-dissolving ability, YP-1is the best taking sucrose as carbon, YP-4is the highest under glucose as carbon source, YP-1gets the top with ammonium sulfate as nitrogen, and YP-4is the first nitrate of potash as nitrogen.(4) In this study, Sephadex G-150gel filtration column was used to pure supernatant protein of YP-1and YP-4. Main peak proteins were collected which posses phosphate-solubilizing enzyme activity. SephadexG-150gel filtration chromatography and SDS-PAGE show the size of extracellular protein with phosphate-solubilizin enzyme activity in YP-1and YP-4were38.6kD,34.9kD respectively.