Screening of the agents and antagonistic bacteria to Pectobacterium carotovorum subsp. brasiliense

Bacterial soft rot of potato, caused by Pectobacterium carotovorum subsp. brasiliense（Pcb）, is one of the most important diseases in the world. It is widespread and serious in potato producing areas in China and usually causes huge economic losses. Little investigation has been done on applications of chemical and biological control to the disease in China. In this study, Pcb was used as the indicator bacteria against nine kinds of chemical agents to develop effective chemicals on the plate experiment. Four kinds of chemicals, including Wanshengqing（20% bromothalonil + 5% cuppric nonyl phenolsulfonate）, gramcazole （3% zhongshengmycin）, octyl amine acetate and Kecocon（1.5% thiazolone）have acquired good antibacterial effect on Pcb respectively. Further investigation showed that five antagonistic bacterial strains which were isolated from soils have good bacteriostatic activities to Pcb and were preliminarily identified as Pantoea ananatis, Serratia marcescens, Pseudomonas plecoglossicida and Staphylococcus sciuri by 16S rDNA, respectively. The antagonistic bacterial strain of RFjk2 which was identified as Serratia marcescens showed a potential application on biological control of potato soft rot. The results would lay the foundation for the chemical and biological control to bacterial soft rot of potato.