辣椒疫霉病对辣椒采后经济效益造成了较大损失，但目前暂未见关于采后辣椒疫霉病的生物防治研究。该试验从自然发酵蔬菜中分离筛选出一株对辣椒疫霉菌具有抑制效果的乳酸菌O2，其对辣椒疫霉菌的菌落生长抑制率为87.18%，经16S rDNA和生理生化实验鉴定其为植物乳杆菌（Lactobacillus plantarum）。采用固体稀释法分析O2发酵上清液的理化特性、对辣椒疫霉菌的最小抑菌浓度（MIC）和最小杀菌浓度（MBC），采用固体稀释法和牛津杯法分别测定O2发酵上清液对辣椒采后致病菌和部分食源性致病菌的抑菌图谱。结果表明，O2发酵上清液对过氧化氢酶、蛋白酶K、胰蛋白酶、胃蛋白酶不敏感，在温度40~120 ℃和15 W紫外灯照射30~150 min、pH值5范围内抑菌物质稳定，对辣椒疫霉菌的MIC和MBC分别为12.8 mg/mL和25.6 mg/mL，对红色炭疽菌、大肠杆菌、沙门氏菌、志贺氏菌和阪崎肠杆菌具有显著抑制效果。综上所述，植物乳杆菌O2具有良好的抑制辣椒疫霉菌效果，其代谢产物稳定性好，可作为采后辣椒疫霉病的生物防治菌株进一步开发利用。

The Phytophthora capsici disease has caused great losses to the economic benefits of postharvest pepper, but there has been no study on the biological control of Phytophthora capsici disease in postharvest pepper. In this experiment, a strain of lactic acid bacteria O2 with an inhibitory effect on Phytophthora capsici was isolated and screened from natural fermented vegetables. Its colony growth inhibition rate against Phytophthora capsici was 87.18%. It was identified as Lactobacillus plantarum by 16s rDNA sequence Analysis and based on physiological and biochemical experiments. The physicochemical properties, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the O2 fermentation supernatant against Phytophthora capsici were analyzed by the solid dilution method. The antibacterial profiles of the O2 fermentation supernatant against the postharvest pathogenic bacteria and some foodborne pathogens were determined by the solid dilution method and Oxford cup method. The results showed that the supernatant of O2 fermentation was insensitive to catalase, protease K, trypsin and pepsin, and the antibacterial substances remained stable in the temperature range of 40~120 ℃, after 15 W UV lamp irradiation for 30~150 min, and at pH5. The MIC and MBC of the O2 fermentation supernatant against Phytophthora capsici were 12.8 mg/mL and 25.6 mg/mL, respectively, and exhibited significant inhibitory effects against Colletotrichum gloeosporioides, Escherichia coli, Salmonella, Shigella and Enterobacter sakazakii. In summary, Lactobacillus plantarum O2 has a good inhibitory effect against Phytophthora capsici, and its metabolites high sound stability, thus, can be further developed and utilized as a strain for biological control of postharvest Phytophthora capsici disease.

湖南省重点研发计划项目（2021NK2014）；湖南省研究生创新科研项目（CX20220683）；湖南农业大学研究生创新科研项目（2021.63）；长沙市自然科学基金资助项目（kq2202224）；湖南农业大学第三批重大科研项目（创新团队培育工程2019）；湖南农业大学“双一流”学科建设项目（SYL2019061）