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Etiology

Erwinia chrysanthemi: Serological Comparisons of Strains from Zea mays and Other Hosts. Robert S. Dickey, Professor, Department of Plant Pathology, Cornell University, Ithaca 14853; Larry E. Claflin(2), and Cathy H. Zumoff(3). (2)Associate professor, Department of Plant Pathology, Kansas State University, Manhattan 66506; (3)Research technician, Cornell University. Phytopathology 77:426-430. Accepted for publication 20 August 1986. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/Phyto-77-426.

Four types of reactions were observed in Ouchterlony double diffusion tests when 47 strains of Erwinia chrysanthemi originally isolated from Zea mays or Zea mays var. rugosa and 131 strains from 40 different hosts were tested with antisera produced against two glutaraldehyde-treated strains from corn. The reactions observed included: a strong primary precipitin band, a strong primary band plus a weak secondary band, only a weak secondary band, or no bands. A strong primary band was used to designate serovar groups; however, only four strains produced a primary band with either antiserum. Three of the strains, originally isolated from corn, reacted with one antiserum and were included in a new group that was designated serovar V, whereas the fourth strain previously assigned to serovar II group reacted with the other antiserum. Thirty-seven strains produced only secondary bands with the two antisera; 20 of the strains were isolated originally from corn and 17 were isolated from nine different hosts. The secondary bands were shown to be similar, if not identical, by fusion of the bands and by cross absorption tests. Although only corn strains produced primary bands, there was no definite relationship between production of secondary bands and the original host, geographical location, and phenotypic characteristics of the strains. Thirty-three strains of other Erwinia species or subspecies did not react with the two antisera. The results demonstrated the specificity of the antisera for strains of E. chrysanthemi, the heterogeneity of the antigenic properties of strains and the limitations of the antisera for diagnoses and identification of phytopathogenic strains isolated from corn plants.