Generation of transgenic asulam-resistant potatoes to facilitate eradication of parasitic broomrapes (Orobanche spp.), with the sul gene as the selectable marker

Root-attaching parasitic flowering broomrapes (Orobanche spp.) are major constraints to vegetable, legume and sunflower production around the Mediterranean and elsewhere, with banned methylbromide fumigation or land abandonment of these affected crops as the major "solutions" to the problem. We report the specific generation of transgenic asulam-resistant potatoes as a way to eradicate this pest. The target-site resistance in the crop allows the herbicide to be translocated from treated leaves to the parasite via crop roots. This inhibitor of dihydropteroate synthase lethally then prevents folic acid biosynthesis in the parasite. Additionally, we demonstrate that asulam can be used directly in selecting resistant transformants, without the need for another selectable marker.