Journal Article

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

Iruegas-Bocardo, Fernanda, Doan, Tien Thi Kieu, Kebede, Misrak, Huguet-Tapia, Jose C., Osdaghi, Ebrahim, Roach, Rebecca, Bernal, Eduardo, Félix-Gastélum, Rubén, Minsavage, Gerald V., Jones, Jeffrey B., Luo, Laixin, Thummabenjapone, Petcharat, Jibrin, Mustafa O., Miller, Sally A., Louws, Frank J., Subedi, Aastha, Adhikari, Pragya, Cirvilleri, Gabriella, Egel, Daniel S., Kaur, Amandeep, de la Barrera, Laura Belen Tapia, Ivey, Melanie Lewis, Trueman, Cheryl, Klein-Gordon, Jeannie, Rotondo, Francesca, Roberts, Pamela D., Adhikari, Tika B., Goss, Erica M., Creswell, Tom C., Vallad, Gary E., Sharma, Anuj, Francis, David M., Maynard, Elizabeth T., Nguyen, Nga Thi Thu, Quezado-Duval, Alice M., Timilsina, Sujan, Coutinho, Teresa A., Shutt, Vou M., Ruhl, Gail E.

2025

Overview

Emerging and re-emerging plant diseases continue to present multifarious threats to global food security. Considerable recent efforts are therefore being channeled towards understanding the nature of pathogen emergence, their spread and evolution. Xanthomonas euvesicatoria pv. perforans (Xep ) , one of the causal agents of bacterial spot of tomato, rapidly emerged and displaced other bacterial spot xanthomonads in many tomato production regions around the world. In less than three decades, it has become a dominant xanthomonad pathogen in tomato production systems across the world and presents a compelling example for understanding diversification of recently emerged bacterial plant pathogens. Although Xep has been continuously monitored in Florida since its discovery, the global population structure and evolution at the genome-scale is yet to be fully explored. The objectives of this work were to determine genetic diversity globally to ascertain if different tomato production regions contain genetically distinct Xep populations, to examine genetic relatedness of strains collected in tomato seed production areas in East Asia and other production regions, and to evaluate variation in type III secretion effectors, which are critical pathogenicity and virulence factors, in relationship to population structure. We used genome data from 270 strains from 13 countries for phylogenetic analysis and characterization of type III effector gene diversity among strains. Our results showed notable genetic diversity in the pathogen. We found genetically similar strains in distant tomato production regions, including seed production regions, and diversification over the past 100 years, which is consistent with intercontinental dissemination of the pathogen in hybrid tomato production chains. Evolution of the Xep pangenome, including the acquisition and loss of type III secreted effectors, is apparent within and among phylogenetic lineages. The apparent long-distance movement of the pathogen, together with variants that may not yet be widely distributed, poses risks of emergence of new variants in tomato production.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Agriculture / Bacteria, Phytopathogenic / Biological diversity / Copper / Distribution / Diversification / Effectors / Environmental conditions / Epidemics / Epidemiology / Evolution / Food security / Food supply / Genes / Genetic aspects / Genetic diversity / Genetic Variation / Genomes / Gram-negative bacteria / Identification and classification / International economic relations / Microbiological research / Pathogenicity / Pathogens / Phylogenetics / Phylogeny / Plant diseases / Plant Diseases - microbiology / Population genetics / Population structure / Seeds / Solanum lycopersicum - microbiology / Spot / Strains (organisms) / Tomatoes / Vegetable industry / Virulence factors / Xanthomonas - classification / Xanthomonas - genetics / Xanthomonas - pathogenicity / Xanthomonas euvesicatoria