What keeps Tomato growers up at night? Xanthomonas. They are the genus of proteobacteria responsible for Bacterial Spot, which is a disease that wreaks havoc on Tomato plants. The trouble with Xanthomonas is that there is enough genetic variability within the genus that plant breeders have a hard time coming up with resistant plant varieties and pathologists are unable to create a chemicals to combat the disease. As of now, farmers are stuck using the same control mechanisms they’ve been using for half a century: Copper based pesticides. Although they’ve been effective, they are expensive and must be applied frequently. Copper based pesticides are also indiscriminate in terms of what they kill. Beneficial insects, soil bacteria, fungi, etc. are all affected by copper based pesticides.
Scientists like Dr. Sam Hutton (featured in this video) are working on transgenic tomato plants that resist bacterial spot. They’ve managed to find resistance in a relative of tomatoes (sweet peppers), and have had great success with resistance in trials. Trouble is, willing tomato operations are required to scale up the transgenic solution to bacterial spot. If no willing growers can be found, this tomato may never do what it was designed to do: help farmers overcome a troubling plant disease.
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