Diversification of an emerging bacterial plant pathogen; insights into the global spread of Xanthomonas euvesicatoria pv. perforans

Abstract

Bacterial diseases pose significant threats to food security by reducing crop yield and increasing production costs. Managing these diseases is particularly challenging when pathogen populations are genetically diverse, rapidly evolving, and capable of long-distance dispersal. Xanthomonas euvesicatoria pv. perforans (Xep), one of the pathogens responsible for bacterial spot disease of tomato, exemplifies these challenges. Since its discovery in Florida in 1991, Xep has spread globally, affecting tomatoes in warm and wet production regions worldwide. Previous studies have indicated genetic diversity within Xep, suggesting the emergence of multiple lineages, but there was not a comprehensive global analysis. Here, we examined genome sequences of Xep strains from five continents and discovered extensive genetic diversity, including in genes important for virulence and breeding for resistance in tomatoes. In addition, we found that genetically similar strains were present on different continents, likely due to the international movement of contaminated seeds through global production chains. Our findings underscore the need for periodic monitoring of these pathogen populations and new approaches to effectively manage bacterial spot disease of tomato.