Isolation And Identification Of Two Biocontrol Streptomyces Strains And Their Biocontrol Effect On Plant Disease

Agricultural antibiotics were mainly obtained from the secondary metabolites ofactinomycetes. Screening the most effective isolate from the various microorganisms in the soilenvironment was the basic work of developing newly agricultural antibiotic product, which also isthe pathway to solve bottleneck of agricultural antibiotic. Therefore, screening high potentialactinomycete strains is the aim of this study. Based on the result of biocontrol control effect,2potential biocontrol streptomycete strains, isolated from soil samples of Mount Emei, wereobtained and indentified.（1）221actinomycete strains were isolated from the soil samples collected from Mount Emeiat different altitude by10-fold serious dilution. There were72actinomycete strains withantifungal activity, which is33%of all the isolations。（2）42actinomycete strains with stable antifungal activity were obtained by the dual-culturemethod. Three strains, which producted metabolites aganist plant pathogenic fungi, weredetermined through the growth rate determination method. Strains C1905and5071effectivelyinhibited Rhizotonia cerealis, and the inhibitory rates were79.07%and73.26%, respectively. Theinhibitory rates of strains1706against Fusarium graminearum and Valsa mali were75.58%and61.63%, respectivly.（3）The result of potting experiment shows that the control effect of strains1706and C1905against wheat powdery mildew and strawberry powdery mildew were about62%and80%respectively. Control effect of strain C1905on wheat powder mildew was69%, and moer than70%on strawberry powdery mildew.（4）Strain1706and C1905were indentified as Streptomyces rishiriensis and Streptomyceslavendulae by means of16S rDNA sequences analysis based on the culture characteristics,physiological and biochemical characteristics determination.