Sensitive and specific detection of Xanthomonas hortorum pv. pelargonii in geranium by real-time PCR

Xanthomonas hortorum pv. pelargonii is the causal agent of bacterial blight of geranium. A specific and rapid real-time PCR assay for detecting the bacterium in plant was developed in this study. We compared sensitivity of conventional and real-time PCR for detection of the pathogen in inoculated plants. For application to disease management programs, PCR amplification must be able to detect latent infections of asymptomatic geraniums. Our results displayed that conventional PCR lacks sufficient sensitivity to be used as diagnostic tools for detection of X. hortorum pv. pelargonii in latent infections. On the other hand, real-time PCR is suitable method for detection of latent infection of the bacterium in planting materials and can be considered in management programs. The ability for accurate and reliable detection of X. hortorum pv. pelargonii in asymptomatic tissue is a significant step in setting up “pathogen free” certification programs for bacterial blight of geranium.