Abstract: 【Objective】The objective of this study is to develop a duplex PCR system to simultaneously and reliably detect Clavibacter michiganensis subsp. sepedonicus and Pectobacterium atroseptica. 【Method】 Choosing the cellulose A gene sequence encoded by the native plasmid pCS1 of C. michiganensis subsp. sepedonicus which was published on the GenBank and comparing it with the nucleotide sequence of closely-related species and some pathogens of potato, a specific pair of primers, CMS1/CMS2, was designed and synthesized. A duplex PCR system had been established under the optimized PCR parameters using the combining primers CMS1/CMS2 and ECA1f/ECA2r which was a specific pair of PCR primers to detect P. atroseptica. 【Result】 Using CMS1/CMS2 primers, a single unique PCR band of 913 bp was amplified from C. michiganensis subsp. sepedonicus. The detection sensitivity was 100 fg•μL-1 of DNA and 105 CFU•mL-1 of bacteria. Under the duplex PCR system, the 913 and 690 bp PCR bands from P. atroseptica could be specifically amplified. The detection sensitivity was 600 fg•μL-1 of DNA and 5×105 CFU•mL-1 of bacteria.【Conclusion】The duplex PCR system could simultaneously and rapidly detect the two pathogens.

Key words: potato, Clavibactermichiganensissubsp.sepedonicus, Pectobacteriumatroseptica, duplexPCR, moleculardetection