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Use of Monoclonal Antibodies Specific for Pectate Lyase as Serological Probes in the Identification of Soft Rot Erwinia spp.. M. J. Klopmeyer, Former postdoctoral research associate, Department of Plant Pathology, University of Wisconsin-Madison, 1630 Linden Drive, Madison 53706; A. Kelman, professor, Department of Plant Pathology, University of Wisconsin-Madison, 1630 Linden Drive, Madison 53706. Phytopathology 78:1430-1434. Accepted for publication 23 June 1988. Copyright 1988 The American Phytopathological Society. DOI: 10.1094/Phyto-78-1430.

Polyclonal and monoclonal antibodies (MCAs) were prepared against a purified extracellular endopectate lyase (PL) from Erwinia carotovora subsp. carotovora, causal agent of bacterial soft rot of potato. The antibodies were tested on crude PL preparations from representative soft rot Erwinia spp. including E. c. carotovora, E. c. atroseptica, and E. chrysanthemi in a dot blot immunoassay. The polyclonal anti-PL sera reacted with PL from all soft rot Erwinia spp. tested, but cross-reacted weakly with PL from pectolytic Pseudomonas and Xanthomonas strains. The MCAs reacted with PL from 55 strains of E. c. carotovora, 10 of 11 E. c. atroseptica strains, and most of 20 potato strains of E. chrysanthemi tested. Reaction with PL from 24 non-potato E. chrysanthemi strains was variable and was not related to the host plant or geographical origin of the strain. The MCAs did not react with PL from pectolytic pseudomonads, a pectolytic xanthomonad, or commercially prepared pectic enzymes from Aspergillus spp.