Serological Characterization of Potato Isolates of Erwinia-Carotovora Subsp Atroseptica and Subsp Carotovora using Polyclonal and Monoclonal-Antibodies

Abstract

Serological, biochemical and physiological characteristics of 81 strains of Erwinia carotovora subsp. atroseptica (Eca) and 67 strains of subsp. carotovora (Ecc) from potato, isolated in Spain and from several international collections, have been studied. Ouchterlony double diffusion (ODD), indirect immunofluorescence (IIF) and indirect enzyme-linked immunosorbent assay (ELISA) were the methods used. The antibodies were polyclonals from eight antisera prepared with Era serogroup I and Ecc serogroup III and tao monoclonal antibodies (MAbs), 4G4 from Spain and 4F6 from Canada, both prepared with Era strains of serogroup I. Serogroup I for Era and several serogroups for Ecc were the most commonly found in the collection studied. Serological relationships between Era and Err independently of the serogroups were observed by IIF and ELISA using polyclonal antibodies. Common epitopes between all Era and Err studied were detected. Both MAbs recognized epitopes in Eca strains of serogroups I and XXII in IIF and ELISA but they did not react with strains of other serogroups nor Err strains. The pattern of reaction against the strains assayed was rather similar but not identical indicating that they represent two different and well conserved epitopes. This study confirms the serological complexity of Err and Era and gives information about the serological probes for detection of both subspecies.