Detection of Clavibacter michiganensis subsp. sepedonicus by DNA amplification.

Control of bacterial ring rot ultimately depends on the accurate and sensitive detection of C. michiganensis subsp. sepedonicus in infected potato tissues and tubers. Polymerase chain reaction (PCR) based detection of C. michiganensis subsp. sepedonicus appears to have the potential to circumvent many of the problems currently associated with detection of this phytopathogen. PCR reactions using primers specific to C. michiganensis subsp. sepedonicus and genomic DNAs from related strains, including phytopathogens, did not produce any amplification products. C. michiganensis subsp. sepedonicus was detectable from a mixture of potato and bacterial DNA by amplification of a DNA sequence specific to C. michiganensis subsp. sepedonicus. Detection by DNA amplification allowed direct processing of plant tissue samples, and circumvented the need for prior isolation of the suspected phytopathogen.