Preliminary Isolation and Identification of the Antagonistic Bacterial Strain 5A5-3 Against Common Orchid Diseases

320 strains were isolated from 10 soil samples collected at Mu Us sandy land of China. After growing confrontation test to Colletotrichum gloeosporioide,57 strains were screened preliminarily. The strain 5A5-3 screened from biological crusts of Mu Us sandy land with a rather higher antagonistic activity against C. gloeosporioide was obtained after secondary screening. The strain 5A5-3 was further identified by morphological and cultural characteristics,physiological and biochemical experiments and 16S rDNA sequence analysis. Based on the results,the strain was finally identified as a Bacillus velezensis. 16S rDNA sequences analysis of strain 5A5-3 revealed that it had100% similarity to B. velezensis CR-502.