Whitefly Resistance In Solanum Section Lycopersicon

Whiteflies (Bemisia tabaci  and Trialeurodes vaporariorum) are a major problem in tomato growing. They cause damage by uptake of phloem, secretion of honeydew, on which sooty molds can grow, and most importantly they transmit viruses.  Whiteflies are difficult to control with insecticides. Also, they develop resistance to the insecticides very quickly. The best strategy is to prevent the problems occurring using whitefly resistant varieties.  Resistance towards whiteflies is found in wild relatives of the cultivated tomato. Well known sources are Solanum pennellii and S. habrochaites.  Whitefly resistance is based on chemical compounds present in the glandular trichomes and different species contain different compounds toxic to whiteflies.  Attempts to use these wild species as sources of resistance have until now not resulted in whitefly resistant tomatoes. This is most likely because of the complex nature of the resistance in these species. New sources of resistance in species more closely related to the cultivated tomato may be more useful. We have carried out a broad screening for whitefly resistance in Solanum, that resulted in the identification of several new sources of resistance. For one of them, Solanum  galapagense, a mapping population was created, which was genotyped and phenotyped. Phenotyping included insect assays and non-targeted metabolomics. This resulted in the identification of two major QTLs explaining the complete resistance and chemical compounds involved in the resistance.