Abstract: In order to screen antagonistic strains of strawberry gray mold pathogens and provide strain resources for the biological control of strawberry gray mold，the endophytic bacteria with inhibitory effect on strawberry Botrytis cinerea were isolated and screened from healthy strawberry plants by plate confrontation method，the effect of antagonistic strains on the mycelial growth of the pathogen was observed by light microscope，and the antagonistic bacteria and gray mold pathogen were returned to healthy strawberry fruits at the same time for in vivo inhibition，and their antibacterial effects were evaluated.The analyses of morphological，physiological and biochemical characteristics，and 16S rDNA sequence comparison were performed to identify each antagonistic strain. The results showed that 34 bacterial isolates were isolated and purified from healthy strawberry plants.Among them，five strains with good antagonism performance to strawberry gray mold pathogen were screened through plate confrontation experiments，namely R09，R11，R14，R16 and R22.Their inhibition rates were 67.56%，70.67%，68.11%，65.22% and 63.33%，respectively. Through morphological observation，it was found that all five strains were bacilli with round and opaque colonies，with sizes ranging from 0.321—0.413 μm，0.379—0.582 μm，0.300—0.700 μm，0.500—1.000 μm，and 0.350—0.390 μm，respectively.Based on the morphological，physiological，biochemical，and molecular biological characteristics of each strain，the five endophytic bacteria were identified as Bacillus methylotrophicus，Bacillus siamensis，Bacillus vallismortis，Bacillus velezensis，Bacillus amyloliquefaciens.It was observed that the mycelial morphology of the pathogen in the confrontation area showed obvious deformities，bends，and swelling.The in vivo inhibition test showed that all five antagonistic bacteria had good inhibitory effects on the pathogen of strawberry gray mold，among which Bacillus siamensis had the best effect，the diameters of strawberry lesions was 66.17% smaller than those of CK（without antagoninsti bacteria）.This study expanded the strain resources for the biological control of strawberry gray mold and provided a reference for the production of biocontrol agents for strawberry diseases.

Key words: Strawberry, Gray mold, Antagonistic bacteria, Endophytes, Bacteriostasis, Plate confrontation method, Phylogenetic tree

摘要： 为筛选草莓灰霉病病原菌拮抗菌株，给草莓灰霉病的生物防治提供菌株资源，采用平板对峙法从健康草莓植株中分离筛选对草莓灰霉病菌灰葡萄孢菌具有抑制作用的内生细菌，利用光学显微镜观察拮抗菌株对灰葡萄孢菌菌丝生长的影响，将各拮抗菌和灰霉病病原菌同时回接至健康草莓果实上进行活体抑制试验，评价其抑菌效果。通过形态学、生理生化特征以及16S rDNA序列比对等对各拮抗菌株进行鉴定。结果表明，从健康草莓植株中分离纯化出34株细菌分离株，与草莓灰霉病病原菌平板对峙筛选出5株拮抗性能较好的菌株R09、R11、R14、R16、R22，其对草莓灰霉病菌的抑制率分别为67.56%、70.67%、68.11%、65.22%和63.33%。通过形态观察发现，5种菌株均为杆菌，菌落圆形不透明，大小分别为0.321~0.413、0.379~0.582、0.300~0.700、0.500~1.000、0.350~0.390 μm；结合各菌株形态学、生理生化及分子生物学特征，确定这5株内生细菌分别为甲基营养型芽孢杆菌、暹罗芽孢杆菌、死谷芽孢杆菌、贝莱斯芽孢杆菌、解淀粉芽孢杆菌。对峙培养后病原菌菌丝形态有明显的畸形、弯曲、膨大现象。活体抑制试验显示，5种拮抗细菌均对草莓灰霉病病原菌有较好的抑制作用，其中暹罗芽孢杆菌的效果最佳，草莓病斑直径较CK（未用拮抗菌处理）减小66.17%，为草莓灰霉病的生物防治扩大了菌株资源，为草莓病害生防菌剂生产提供参考依据。

关键词: 草莓, 灰霉病, 拮抗菌, 内生菌, 抑菌作用, 平板对峙法, 系统发育树