The Study On The Culturable Actinomycete Diversity Of The Saline-alkaline Soil In Hexi Corridor In The Winter And On Antagonistic Ability For Rape Pathogen Sclerotinia Sclerotiorum

Three types of saline-alkaline soil were collected from10sample spots in HexiCorridor in Gansu province at this research. The diversity of actinomycetes in thesaline-alkaline soil was researched. Simultaneously, combined with the soil properties,simple correlation analysis and stepwise regression analysis were conducted. Therelations among actinomycetes diversity, soil enzymes and soil physical-chemicalfactors were researched. In addition, the tolerance test of salinity of dominantactinomycetes was researched. Two actinomycetes strains isolated from the soil showthe inhibition effect on the rape sclerotiniose.8actinomycetes genera were isolated from10soil samples, Streptomyces genusis a major component of actinomycetes, Nocardiopsis and Nocardia were only secondto Streptomyces in component of actinomycetes, and they were important exceptingStreptomyces. In farmland soil, actinomycetes species diversity and quantityconcentrated almost of all in the Streptomyces genus; actinomycetes species diversityand quantity concentrated mainly in the Streptomyces genus in secondary saline soiland native saline soil too, but other actinomycetes genera were also embodied,Nocardiopsis and Nocardia were especially. Whether dominant species diversity andquantity, Streptomyces ratio was farmland soil> secondary saline soil> native salinesoil in actinomycetes.11groups were isolated from14groups of Streptomyces genus,Albosporus, Flavus, Globisporus and Aureus distributed wide comparatively,Albosporus was the most primary in Streptomyces genus.The most dominant actinomycetes strains were carried out phylogenetic analysisof16S rRNA gene sequences in each soil sample at the highest dilution. The primaryresults showed: X23-5-2（KC898851） and X23-5-4（KC898849） were new species ofStreptomyces genus from farmland soil X soil samples, another9strains ofStreptomyces and1strains of Nocardiopsis could be new species in doubt.The simple correlation analysis and stepwise regression analysis had been carriedout simple for physical and chemical factors of3saline soil types with the quantityand diversity of actinomycetes and their predominant species. The results showed that the most intimate relation to soil environmental factors was the quantity ofStreptomyces. pH was the most important in these soil environmental factors. As theraise of pH, conductivity, Na⁺, Cl^-and SO₄^2-, the activity of soil enzyme could bedropped, then the ratio of the quantity and diversity of Streptomyces could be dropped,other genera of actinomycetes could be raised.In the most dominant47strains, only strains Ⅰ8-5-2, Ⅱ8-4-4and Ⅹ8-5-1could not tolerant5%NaCl concentration; all other tested strains could tolerant5%NaCl concentration All of the tested strains could not tolerant10%NaClconcentration and their salt-tolerant ability was same. All of the tested strainspossessed strong ability of tolerance alkaline, most of strains could grow well atpH9.0, the part of strains could tolerant pH10.0, even pH11.0.Two strains expressing significant ability of inhibiting the rape pathogenSclerotinia sclerotiorum were isolated from the saline-alkaline soil, their serialnumder were Ⅳ22-3-3and Ⅳ22-3-12. They were identified as Streptomycehydrogenas（Ⅳ22-3-3） and Streptomyce globisporus（Ⅳ22-3-12）.The study on diversity of actinomycetes in saline-alkaline soil of Hexi Corridoris beneficial to understand the actinomycete population, distribution and resources inthis important ecological and agricultural area. It provided effective basic data for theuse and development of actinomycetes.