Researchers Tackle Crown Gall in Woody Ornamentals
June 9, 2020 
Photo: Kamil Duman
Crown gall can be a devastating disease in woody ornamentals, shrubs, and roses. Crown gall, which results from the spread of Agrobacterium, affects more than 100 greenhouse and nursery species valued at $16.2 billion in annual economic activity in the U.S. It also is particularly problematic in hydroponic crop growing.
Recently, USDA Agricultural Research Service (ARS) scientists and their Oregon State University (OSU) collaborators have developed a new, highly detailed genetic way to trace the spread of Agrobacterium, one of the world’s most important bacterial plant pathogens, according to research just published in Science.
What gives Agrobacterium its virulence is the presence of plasmids inside the bacterial cells. Plasmids are autonomously replicating DNA molecules that have become part of the bacterium, but are not essential to the physiology of the cells. These plasmids have genes that give Agrobacterium the unique ability to transfer a portion of the plasmid into plant cells and genetically reprogram the host to cause disease.
These plasmids also have genes that allow Agrobacterium to transfer the entire plasmid horizontally from one bacterium to another, rather than only vertically as in parent to offspring. Once acquiring a harmful plasmid, a previously benign strain of Agrobacterium can become a novel pathogen line. This ability has made control of the pathogen and tracking of an outbreak very difficult.
Learn more about this research here.
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