According to a news release from the 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.
Agrobacterium causes crown-gall disease in fruit trees (apple, cherry, berry, walnut), woody ornamentals and shrubs including roses, herbaceous perennials, grape vines, and shade trees, in all affecting more than 100 greenhouse and nursery species valued at $16.2 billion in annual economic activity in the United States. It also is particularly problematic in hydroponic crop growing.
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.