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Etiology

Serogroups of Erwinia carotovora Potato Strains Determined with Diffusible Somatic Antigens. S. H. De Boer, Research plant pathologist, Research Station, Agriculture Canada, 6660 N.W. Marine Drive, Vancouver, British Columbia, V6T 1X2; R. J. Copeman(2), and H. Vruggink(3). (2)Associate professor, Department of Plant Science, University of British Columbia, Vancouver, V6T 1W5; (3)Research associate, Institute of Phytopathological Research, Wageningen, The Netherlands. Phytopathology 69:316-319. Accepted for publication 5 October 1978. Copyright 1979 The American Phytopathological Society. DOI: 10.1094/Phyto-69-316.

Antisera produced against selected potato strains of Erwinia carotovora were used to classify unknown strains of E. carotovora into serogroups. The basis of a serogroup was a reaction of identity with the homologous strain by double diffusion. The antigen responsible for precipitin band formation was heat stable and could be extracted with a conventional phenol-water extraction procedure for lipopolysaccharides. Approximately 83% of 1,001 strains from several culture collections could be classified in one of 18 serogroups that were established. In a survey of E. carotovora strains in British Columbia, five serogroups were found frequently; other serogroups were isolated rarely or not at all. Most strains identified as E. carotovora var. atroseptica belonged to one serogroup, but 14 strains belonged to a second serogroup which also accommodated two strains that were biochemically identified as E. carotovora var. carotovora. The two E. carotovora var. atroseptica serogroups were serologically related and one of these also was related to an E. carotovora var. carotovora serogroup.