CHARACTERIZATION OF RALSTONIA SOLANACEARUM CAUSING BACTERIAL WILT IN BELL PEPPER IN THE STATE OF PERNAMBUCO, BRAZIL

Abstract

Seventy-seven bacterial strains obtained from wilted bell pepper plants from the Agreste and Mata mesoregions of Pernambuco State (northeastern Brazil), were identified as Ralstonia solanacearum using multiplex PCR. The strains were further analyzed to characterize their biochemical, physiological, and molecular diversities. The biovars and biotypes were determined biochemically, and a molecular characterization of the strains was made using multiplex PCR, rep-PCR, and ISSR. The genotypic diversity was assessed, considering the number of genotypes observed and how they were distributed throughout the populations, for their differences in terms of richness, evenness and diversity. Strains of biovar 3, biotype 8 and phylotype I were predominant (97.40%), but biovar 1, biotypes 3 and 6 and phylotype II were also present. Rep-PCR analysis using REP and BOX primers, and ISSR showed similarities among the majority of the strains; however, these primers did not allow strain separation by biovars, biotypes, phylotypes or areas. Analysis of the genotypic diversity revealed a moderate diversity in the overall population, with a high variability in the strains from the same municipality.