Predicting the evolutionary fate of a virus resistant transgene in wild populations of Cucurbita pepo

Gene exchange between crops and their wild relatives is common and difficult to contain.  Unlike most traits of cultivated species, there are concerns that transgenes conferring resistance to herbivores or pathogens could enhance the fitness and weediness of wild species.  Gene flow between cultivated squash and its wild counterpart (Cucurbita pepo ssp. texana) may result in the introduction of a transgene that confers resistance to three common viruses in wild populations.  The fitness of the transgene during escape is influenced by the full ecological community as indirect costs associated with increased exposure to herbivory by cucumber beetles and the bacterial wilt disease they transmit can mitigate the fitness benefits of the VRT.  We have extensively studied the interactions among C. pepo, its primary herbivores (cucumber beetles and aphids), and the pathogens they transmit (Erwinia tracheiphila, the causative agent of bacterial wilt, and three mosaic viruses).  Unlike previous studies which typically challenge host plants with individual natural enemies, our experiments occurred in naturalistic settings in order to capture the complex interactions that occur between the plants, herbivores, and pathogens in nature.  Using a game theoretical model we can compare the competing strategies of transgenic and non-transgenic plants in the presence of both pathogens and determine not only if the virus resistant transgene can successfully invade a population of non-transgenic plants, but at what frequency transgenic plants will be present in the population.