UNIVERSITY PARK, Pa. — A nearly $4 million grant awarded to Penn State will support an interdisciplinary, multi-university team of researchers as they explore bacterial pathogens causing leaf spot diseases that are damaging valuable agricultural crops such as watermelon and pumpkin.
The grant, from the U.S. Department of Agriculture's National Institute of Food and Agriculture, will be supplemented by nearly $3 million in matching investments from seed companies and associated industries and over $1 million from the universities involved, according to project director Carolee Bull, professor and head of the Department of Plant Pathology and Environmental Microbiology in the College of Agricultural Sciences.
In addition to advancing the science the research will have real-world impacts, and members of the industry are equal partners in the research and support for the project.
“Beets, Swiss chard, squash, cantaloupe, watermelon, zucchini and pumpkin are among the victims of bacterial pathogens that these crops carry to the field in and on their seeds,” said Bull, who also serves as the director of Penn State’s Microbiome Center, which is housed in the Huck Institutes of the Life Sciences.
“These diseases have devastating effects on these crops. Home gardeners also may be plagued by these diseases in their home plots. We have put together a world-class team and are thrilled that the USDA and the international seed industry recognize the value of our research and the important contributions it will have on global seed and plant health.”
Bull explained that seedborne bacterial leaf spot diseases are caused by a group of related bacteria in the species P. syringae, which contaminate or infect seeds or can infect plants via wounds or natural openings. Once the bacterium enters a plant, it multiplies and causes black lesions that reduce the plant’s ability to photosynthesize and make its own nutrients to grow.
These diseases have increased in frequency and are recognized as a major economic threat to agricultural production. In fact, in 2017, the prevalence of bacterial leaf spot diseases was 75%, and the average incidence was 80% in New York beets.
Likewise, from 2013 to 2014, disease outbreaks caused by P. syringae destroyed an estimated 8,000 acres of watermelon and squash in Florida, including major commercial production areas. Seed infestation has been identified as the main factor contributing to both long distance dissemination of the pathogen and its introduction into new geographic areas.
Bull will serve as project director for a team of university, government and industry scientists, including postdoctoral scholars and graduate students, as they embark on a four-year study of the biology and epidemiology of the pathogens causing this disease in crops grown for seed and those grown for food. The researchers will study seed microbiomes and use diagnostic metagenomic and other approaches to detect the pathogens in and on the seed.