Research of bacterial spot of tomato illuminates pathogen’s diversity throughout Florida during production season

American Phytopathological Society

Florida is the largest producer of fresh market tomatoes in the United States, accounting for a third of the nation’s fresh market tomatoes. The state’s hot, humid climate makes tomatoes more susceptible to outbreaks of bacterial pathogens, such as the one that causes bacterial spot of tomato, which can adversely affect yield. Currently farmers have few options for controlling this disease once it starts to spread.

To learn more about this disease, University of Florida scientists characterized 585 strains of the pathogen collected across 70 Florida commercial tomato fields. They also gathered information about each plant, such as seed producer and seedling origin. They then identified associations between these data points, finding that both farms and transplant facilities could be important points of pathogen spread.

“We knew that the pathogen population on tomato was changing in Florida, but this study included many fields across the state that we were able to get a big picture view of the diversity of the pathogen in Florida (and south Georgia) overall and at the field level,” said Jeannie Klein-Gordon, a plant pathologist from the University of Florida in Gainesville who is now at Michigan State University.

Klein-Gordon and her UF colleagues identified genetic associations between traits and new genetic variation. They also discovered that the overall pathogen population in Florida, and even within single fields, is very diverse, suggesting multiple points of pathogen introduction and spread.

By understanding the pathogen’s population in tomato fields, researchers can provide more effective treatment strategies for growers and work with breeders to ensure better cultivar success in the future. The tomato industry can use this data to more effectively focus management efforts at points of entry in the production system.

“To our knowledge, this is the largest collection and characterization effort for a bacterial plant pathogen within a single production season within a limited geographic area,” said Klein-Gordon. “Our research shows the ability of plant pathologists to combine large-scale surveys with network analyses to study pathogen spread and population structure.”

Klein-Gordon and her colleagues thank the Florida tomato growers for their assistance with this study. To learn more, read “Assessing Changes and Associations in the Xanthomonas perforans Population Across Florida Commercial Tomato Fields Via a Statewide Survey” published in Phytopathology.

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