The whitefly pest and vector, and the geminiviruses that it transmits, have become the principal deterrents to vegetable production in the U.S. sunbelt states, in Mexico, and throughout the Caribbean Basin since the introduction and spread of the B biotype whitefly vector in the late 1980's. The most effective means of controlling geminivirus-incited diseases is through resistant tomato varieties. The proposed research is designed to develop pathogen derived resistance using genetic engineering. Dominant defective versions of the geminivirus transcription activator protein (TrAP) will be expressed in transgenic plants which will mimic wild type protein in most respects, but will be unable to activate transcription. These defective proteins are expected to interfere with the wild type TrAP protein of an incoming virus. The proposed work will take advantage of a powerful combination of interdisciplinary expertise from industry and academia. State of the art information concerning the molecular epidemiology of geminiviruses, predicted evolutionary relationships between viruses, geminivirus replication and transcription strategies, and proven transgenic tomato technology will be employed to develop genetically engineered tomato cultivars with geminivirus specific and/or broad-spectrum resistance.Applications:This research will produce transgenic tomatoes with specific and/or broad-spectrum resistance to whitefly transmitted geminiviruses. The availability of virus resistant tomatoes will avoid the heavy use of pesticides that is presently used for the control of whiteflies in the field. The demonstration of the proposed pathogen derived resistance genetic engineering approach in tomato will provide a sound experimental basis for using this technology in other horticultural industries.
