Strains of the group I lineage of Acidovorax citrulli, the causal agent of bacterial fruit blotch of cucurbitaceous crops, are predominant in Brazil.

摘要: Bacterial fruit blotch (BFB), caused by the seedborne bacterium Acidovorax citrulli, is an economically important threat to cucurbitaceous crops worldwide. Since first report of BFB in Brazil 1990, outbreaks have occurred sporadically on watermelon and, more frequently, melon, resulting significant yield losses. At present, genetic diversity and population structure A. citrulli strains remain unclear. A collection 74 isolated from naturally infected tissues different cucurbit hosts between 2000 2014 18 reference other countries were compared pulsed-field gel electrophoresis (PFGE), multilocus sequence analysis (MLSA) housekeeping virulence-associated genes, pathogenicity tests seedlings species. The Brazilian comprised predominantly group I (98%), regardless year isolation, geographical region, or host. Whole-genome restriction digestion PFGE revealed that three unique previously unreported haplotypes (assigned as B22, B23, B24) Brazil. greatest (four haplotypes) was found among collected northeastern region Brazil, which accounts for than 90% country's melon production. MLSA clearly distinguished into two well-supported clades, agreement with observations based analysis. Five strains, representing haplotypes, moderately aggressive four II highly aggressive. In contrast, no differences severity observed squash seedlings. Finally, we a differential effect temperature vitro growth representative haplotypes. Specifically, tested, all grew at 40 41°C, whereas only 3 15 (haplotypes B8[P], B3[K], B15) 40°C. Three haplotype B8(P) 41°C. These results contribute better understanding associated reinforce efficiency assessing structure. This study also provides evidence suggest might be driver ecological adaptation populations.