Xanthomonas

A genus of Gram-negative, aerobic, rod-shaped bacteria, several species of which are important plant pathogens. Xanthomonas campestris causes black rot of cabbages and cauliflowers, common blight of beans, and bacterial spot of tomatoes and peppers, cutting yields and market quality, while X. fragariae, X. ampelina, and related species attack other crops. Ironically, the same species is industrially precious: X. campestris ferments sugars into xanthan gum, one of the food industry’s most important thickeners and stabilisers. The genus thus spans crop disease and food ingredient production, and its study links plant pathology with industrial biotechnology. Control of the pathogens relies on clean seed, crop rotation, and resistant varieties.