J. Dreier et al., SOUTHERN HYBRIDIZATION AND PCR FOR SPECIFIC DETECTION OF PHYTOPATHOGENIC CLAVIBACTER-MICHIGANENSIS SUBSP MICHIGANENSIS, Phytopathology, 85(4), 1995, pp. 462-468
Clavibacter michiganensis subsp. michiganensis is the causal agent of
bacterial wilt and canker in tomato (Lycopersicon esculentum). Specifi
c detection of this important bacterial pathogen was possible using So
uthern hybridization with DNA-probes derived from plasmid-borne genes,
celA encoding an endocellulase and pat-1 involved in pathogenicity. T
he celA probe differentiated the C. m. subsp. michiganensis, insidiosu
s, nebraskensis, tessellarius, and sepedonicus; moreover, the pat-1 pr
obe distinguished virulent from avirulent strains of C. m. michiganens
is. A polymerase chain reaction based on primers derived from the pat-
1 region was developed. Virulent strains were detectable in homogenate
s prepared from infected tomato plants, naturally contaminated seeds,
and healthy plant homogenates containing as few as 2 X 10(2) bacteria
per milliliter.