Dr. Burr's research on grape crown gall is aimed at furthering and transferring knowledge that will assist the grape industry in managing the disease. His lab developed a very sensitive method for detecting the grape crown gall pathogen, Agrobacterium vitis, which has led to greatly elucidating its presence in association with grapes and a better understanding of its biology in vineyards. They determined that the bacterium is randomly distributed systemically in dormant grape canes and can also be detected in dormant buds as well as on surfaces of leaves and shoots during the growing season. Therefore, the pathogen can survive internally as well as externally. They were also able to determine that wild grapevines in NY as well as in CA often carry the crown gall pathogen. They are currently finishing a project to determine if “clean” vines can be produced through tissue culture propagation. 

Another component of Tom's work involves the development of biological control for the disease. This has involved studying a strain of A. vitis, F2/5, that does not cause crown gall but is able to inhibit crown gall infections specifically on grape wounds. The mechanism of inhibition is still unknown however, they have determined that it is not caused by antibiosis. Pathogenic strains of A. vitis are not killed by F2/5 but are prevented from causing infection specifically on grapevines. F2/5, like other strains of A. vitis, causes necrosis of grape tissue and therefore they have worked to develop a derivative strain that does not cause grape necrosis but still is inhibitory to crown gall. Currently, they are working towards developing a commercial product utilizing this F2/5 derivative.

October 6, 2017 
Dr. Thomas J. Burr, Professor, College of Agriculture and Life Sciences, Cornell University