Abstract: In order to control the soft rot of pear fruit,the antagonistic bacteria against Rhizopus stolonifer were screened from endophytes isolated from different plants,and their biocontrol efficiency was investigated. Plate confrontation method was used to screen the endophytes against R. stolonifer,inoculation pathogen on punched fruit methods was adapted to investigate the efficacy of R1B against pear soft rot,and its antimicrobial substances were preliminarily examined. As results,strain R1B isolated from Dendrobium huoshanense presented antagonistic activities against R. stolonifer,and was revealed as the closest relatives of Bacillus velezensis based on the biochemical characteristics and 16S rRNA gene sequence analysis. The growth of R. stolonifer treated with R1B was almost completely inhibited. The disease incidence of soft rot in the pears treated with strain R1B was totally inhibited,while the control ones completely rotted after 4 days of incubation. The genes of synthesizing antimicrobial peptide（AMP）,bacA（bacylisin）,ituC（iturin）,bmyB（bacyllomicin）,and fenD（fengycin）,were detected in R1B. In sum,bacylisin,iturin and fengycin may be the antimicrobial substances produced by strain R1B. Results clearly suggest that strain R1B is a potential candidate for bio-controlling soft rot of pear fruit.

Key words: Bacillus velezensis, pear soft rot, antagonistic efficacy, Rhizopus stolonifer