Serological detection of Clavibacter michiganensis subsp. michiganensis, a pathogen of tomato [Lycopersicon esculentum] bacterial canker, by enzyme linked immunosolbent assay

The current experiment was carried out to investigate the serological characteristics of Clavibacter michiganensis subsp. michiganensis, a pathogen of tomato bacterial canker, and to apply serological methods to a simple diagnosis and detection of this pathogen. Furthermore, the detection of C. m. subsp. michiganensis by ELISA was studied with these antisera. The results obtained were summarized as follows: 1) Antisera produced to use against two isolates of C. m. subsp. michiganensis were specific toward C. m. subsp. michiganensis, but reacted weakly toward C. m. subsp. sepedonicus, however there was no reaction to other phytopathogenic bacterial strains in the agglutination tests. 2) In the agar double diffusion test, 27 isolates of C. m. subsp. michiganensis were classified into 2 sero-groups. But the precipitin band related classification of the sero-groups showed a very weak reaction. The 27 C. m. subsp. michiganensis isolates which were tested were serologically the same. 3) With these results, it was suggested that the serological methods could be used in a simple diagnosis and detection of C. m. subsp. michiganensis. 4) The detection of C. m. subsp. michiganensis by the ELISA method with a conjugate prepared with anti-YM 7709 serum ws studied. C. m. subsp. michiganensis could be detected over the 1 x 1,000,000 cfu/ml level. 5) The ELISA value in 27 isolates of C. m. subsp. michiganensis and other bacteria was compared. Only C. m. subsp. michiganensis exhibited a high reaction. But, the ELISA value varied according to the isolates. 6) When the population of C. m. subsp. michiganensis on tomato leaves was higher than 1,000,000 cfu per 1g of the leaves, the bacteria could be detected by the ELISA method. 7) The results of these experiments suggest that the ELISA method can be used for detection of C. m. subsp. michiganensis on tomato leaves