Sensitive, Secure Detection of Race 3 Biovar 2 and Native U.S. Strains of Ralstonia solanacearum

Detecting and correctly identifying Ralstonia solanacearum in infected plants is important because the race 3 biovar 2 (R3bv2) subgroup is a high-concern quarantine pathogen, while the related sequevar 7 group is endemic to the southeastern United States. Preventing accidental import of R3bv2 in geranium cuttings demands sensitive detection methods that are suitable for large-volume use both onshore and offshore. However, detection is complicated by frequent asymptomatic latent infections, uneven pathogen distribution within infected plants, pathogen viable-but-not-culturable state, and biosecurity laws that restrict transport of R3bv2 strains for diagnosis. There are many methods to detect R3bv2 strains but their relative utility is unknown, particularly in the realistic context of infected plant hosts. Therefore, we compared the sensitivity, cost, and technical complexity of several assays to detect and distinguish R3bv2 and sequevar 7 strains of R. solanacearum in geranium, tomato, and potato tissue in...