New approach in detecting phytopathogenic bacteria by combined immunoisolation and immunoidentification assays

Antibodies coated onto a suitable solid phase, e. g. polystyrene beads, rods for inoculating agar plates, or petri dishes, enable selective trapping of homologous bacteria and of immunologically related bacteria by immunoaffinity. After washing away unbound organisms, the bound organisms are desorbed and plated on a suitable medium. Selective immunoisolation has been demonstrated for various phytopathogenic bacteria including Corynebacterium michiganense ssp. michiganense, Erwinia chrysanthemi, E. carotovora ssp. atroseptica, Xanthomonas campestris pv. begoniae and Pseudomonas syringae pv. phaseolicola. Three serological methods are described for additional rapid immunoidentification of colonies directly on agar plates and for screening for cross-reacting microorganisms: (a) direct immunodiffusion on dilution plates, (b) agar mixed-antibody assay, (c) fluorescent antibody colony staining. Schemes are presented for increasing the reliability and sensitivity of sample screening for quality indexing of plant material, and for efficient screening and isolation of possible cross-reacting microorganisms to enable production of more specific antisera.