Actinomycetes Population Research And Screening Of Antagonistic Actinomycetes Anti-animal Pathogen From The Saline-alkali Soil In Shiyang River Basin

In this research, five samples were collected from three types of soil in the Shiyang River basin in Hexi Corridor. The cultivate actinomycetes were isolated and analyzed with soil physicochemical properties. There were 298 actinomycetes strasins isolated from 5 soil samples. Streptomyces genus is a major component of actinomycetes, it accounted for 80.53% of all actinomycetes, while the non-Streptomyces accounted for 19.47%. Streptomyces as the dominant genera, with total of 11 taxa and the non-Streptomyces total of 9 genera.From a different sample point of view of actinomycetes were isolated from No.9is the maximum number of soil samples, there are 8 genera and No. 91 was isolated108 strains. Besides Streptomyces genus, the distribution of the rare actinomycetes were also different, some species were isolated in few samples, or could not be isolated. No. 9 sample was isolated 8 genus of rare actinomycetes, it suggested that No. 9 sample have the richest diversity of actinomycetes.Gause’s medium isolated which made the highest number of actinomycetes strains, most of them were Streptomyces genus. In rare actinomycetes, Nocardiopsis,Pseudonocardia and Nocardia were at the relatively high level. The isolate ability of Glycerinum-L-Asparagine Monohydrate medium took the second place. It could isolate 74 actinomycetes strains. The Improved Proline medium could isolate 17 rare actinomycetes species from 7 genus, so it is the most suitable medium for the growth of the rare actinomycetes.The result indicated that the diversity of actinomycetes of 3 soil types, and the quantity of Streptomyces was secondary saline soil>native saline soil>farmland soil and the species diversity was secondary saline soil > farmland soil > native saline soil. whether the diversity of rare genus actinomycetes was secondary saline soil>farmland soil>native saline soil. It can be suggested that secondary saline soil have the richest diversity of actinomycetes.The biggest differences in the soil physicochemical properties is total phosphorus in 5 samples. The variable coefficient was 1.416. The second place was alkaline phosphatase which one’s variable coefficient was 0.8892. Soil properties and the quantity of actinomycetes are closely correlated, and the result of simple correlationanalysis showed that the quantity of Nocardia were the most affected by the soil properties and the catalase was the most important in these soil environmental factors.In this study, we researched the antagonism from 298 actinomycetes strains isolated to four kinds of anti-animal pathogens by agar block method and filter method, and 105 actinomycetes strains with high antagonism activity were screened,it accounts for 35.2% of the 298 actinomycetes strains.After preliminary screening and secondary screening, witch got 11 strains that had better antibacterial effect. The antagonistic strains with excellent antibacterial activity were identified with their morphological characteristics, physiological and biochemical characteristics and 16 S r RNA gene phylogenetic analysis. 11 strains which has excellent antibacterial activity to animal pathogen belong to Streptomyces,DA910318 was Streptomyces atrovirens,DA910321 was Streptomyces malachitofuscus,DA080402 was Streptomyces mirabilis, DA080411 was Streptomyces rochei, DA910314 was Streptomyces graminofaciens, DB090208 was Streptomyces albovinaceus, DC080331 was Streptomyces marokkonensis,DC080325 was Streptomyces althioticus, DE080223 was Streptomyces exfoliates, DE110406 was Streptomyces albogriseolus, and DE110333 was Streptomyces pilosus.