Eliminating the Pathogen Xanthomonas hortorum pv. carotae from Carrot Seeds Using Different Types of Nanoparticles

There exists a wide range of plant pathogens that are commonly referred to as seed-borne pathogens due to their dominant mode of spread. Treating seeds to eliminate such pathogens is therefore very important in contemporary seed production. In the present study, eight types of nanoparticles were evaluated for their effectiveness against Xanthomonas hortorum pv. carotae, a seed-borne pathogen that affects plants of the Apiaceae family. Initially, parameters considering the inhibitory and bactericidal activity of individual nanoparticles were evaluated under in vitro conditions. In this way, three nanoparticles based on copper, silver, and silver/selenium composite were identified as being the most effective. Subsequently, their ability to eliminate Xanthomonas hortorum pv. carotae from artificially infected carrot seeds was tested. This was achieved through the qPCR quantification of the pathogen in 14-day-old plantlets developed from seeds inoculated with Xhc. Based on the obtained results, copper-based nanoparticles were the most effective, resulting in an approximately 10-fold decrease in the occurrence of Xhc in plantlets compared to the untreated control. Taking into account the fact that X. hortorum pathovars also attack other important horticultural crops, the presented results may have a much wider scope than just carrot seeds.