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Physiology and Biochemistry

Characterization of Pseudomonas solanacearum Biovars Based on Membrane Protein Patterns. Maria C. G. Dristig, Graduate student, Departamento de Fitopatologia, Universidade de Bras?lia, 70919, Bras?lia, DF, Brazil; J. C. Dianese, Professor, Departamento de Fitopatologia, Universidade de Bras?lia, 70919, Bras?lia, DF, Brazil. Phytopathology 80:641-646. Accepted for publication 30 November 1989. Copyright 1990 The American Phytopathological Society. DOI: 10.1094/Phyto-80-641.

Membrane proteins were extracted from 65 isolates representing biovars 1, 2, and 3 of Pseudomonas solanacearum. The isolates were from five regions of Brazil and seven host species. The proteins were compared by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. All strains of biovars 1 and 3 had protein bands with approximate molecular masses of 35?37 kDa, which were absent in biovar 2 strains. A similarity matrix, based on the presence, absence, or intensity of an average of 29 different bands, revealed the relationships between strains classified in all three biovars. Comparisons of P. solanacearum to three other nonfluorescent pseudomonads and to four pathovars of Xanthomonas campestris showed close similarity within the first group, contrasting to clear separation from xanthomonads. Virulent, extracellular polysaccharide-producing isolates of P. solanacearum and nonfluidal forms of those same strains had similar protein patterns.