Taxonomic Identification And Resistance Screening Of Actinomycetes

This paper firstly described the status of actinomycetes classification and the application of polyphasicta taxonomy in classification and identification of actinomycetes, the overview of sunflower sclerotiotinia disease were also stated. By combining physical treatments of vibration with different selective media, and the separation effect was analyzed. The 16 S rRNA gene sequences of 42 cultivatable strains isolated from nanji soil samples were determined. The analysis indicated that Bacillus was the predominant bacteria and the predominant group of the actinomyces is the genus Arthrobacter. Strain E3 T showed 16 S rRNA gene sequence similarties of 98.54% to their most closely related species. After the analysis of DNA hybridizations, we can concluded that strain E3 T represents a novel species within the genus Arthrobacter and subjected to polyphasic taxonomy studies.31 cultivatable strains were isolated from soil samples derived from Inner Mongolia Autonomous Region Bayannaoer League Wu- yuan County. The analysis of the 16 S rRNA gene sequence of the isolates showed us that the number of the Streptomyces is the most and no new species discovered.Cells are aerobic, Gram-positive and non-motile. Strain E3 T sharing highest sequence similarities with the type strains of Arthrobacter cryoconiti CGMCC 1.10698T(98.54%),Arthrobacter stackebrandtii CCM 2783T(98.33%)and Arthrobacter alpinus DSM 22274T(98.05%). Levels of DNA–DNA relatedness between strain E3 T and three above-mentioned type strains were 24.32%,23.52% and 21.22%, far below the threshold of 70%. Results of polar lipid acid analyses indicated that strain E3 T have PIM,PI,PG,DPG,GL and unidentified phospholipid. The predominant menaquinone were MK-9(H2)、MK-8(H2) and MK-10(H2). Major fatty acids were anteiso15:0(77.28%),iso16:0(7.40%)and anteiso17:0(4.46%).Based on the results of morphological characteristics, physiological and biochemical characteristics, chemical analysis, phylogenetic analysis and molecular taxonomy study, strain E3 Tis assigned as the type strain of a novel Arthrobacter species and the name Arthrobacter nanjiensis sp.nov. was proposed.An investigation was conducted into the screening of antagonisticmyeetes-fungus from the isolations derived from Inner Mongolia Autonomous Region Bayannaoer League Wu- yuan County. With plate bacteriostasis assays, strain F5 displayed obvious antagonisms against S. sclerotiorum. The width of the antifungal band was 17.83 mm and the inhibitive efficacy maintained stable. Strain F5 and its metabolites showed good anti-fungal activity, the metabolites can also inhibited the formation of sclerotia on the plate. F5 was identified as Streptomyces sp based on the morphologic characteristics and phylogenetic analysis of 16 S rDNA.