Comparative Membrane Protein Characterization of Brazilian Strains of Ralstonia solanacearum

Abstract

SDS-PAGE patterns of outer membrane proteins of Ralstonia solanacearum were compared with those of R. picketti, Erwinia carotovora subsp. carotovora, E. carotovora subsp. atroseptica, Burkholderia gladioli pv. gladioli and B. caryophylli. These species were discriminated easily on the basis of the dominant bands. For intraspecific grouping of R. solanacearum, outer membrane proteins for twenty-three strains isolated from Brazil were extracted by LiCl and analyzed by SDS-PAGE. All strains had protein bands of ca, 30 and 42 kDa. The strains showed various polypeptide patterns associating with the both original hosts and biovar. Major differences among Brazilian strains were detected when comparison was conducted basing on bands of 27, 29, 38 and ranging from 58 to 190 kDa. Biovars 3 and 2 from tomato were discriminated clearly from the other strains by absence of a 58 kDa band. In potato strains, biovar 1 was different from biovar 2 by the presence of 110 kDa band. On the whole, strains of the same biovar isolated from the same host exhibited uniform pattern. The SDS-PAGE profiles of membrane proteins will be useful as a benchmark for an intraspecific grouping of R. solanacearum.