DNA Testing for Phosphine Resistance ——The Future of Resistance Monitoring and Management

摘要

In recent years, monitoring programs have detected increasing levels of resistance to phosphine among pest insect species. Effective management of resistance requires knowledge of the frequency and distribution of resistance genes within populations. Such knowledge-based management strategies will require rapid, high-throughput resistance assays. Our research is focussed on genomic approaches to identifying phosphine resistance genes in two of the major worldwide pests of stored products, Tribolium castaneum and Rhyzopertha dominica. These genes will then be used in rapid diagnostics to provide data on resistance gene distribution. Our results to date indicate that in both T. castaneum and R. dominica, high-level resistance is mediated by two major genes, each of which confers weak resistance, butwhich interact synergistically to provide high-level resistance. For R. dominica, the genes appear to be the same in all outbreaks yet studied,which suggests they are conserved in most(if not all) cases of high level resistance. This observation enhances the validity of a DNA based test for phosphine resistance, at least in a great majority of cases. Data produced by DNA testing can be used to model the spread of resistance, to indicate pest management strategies that may be deemed at "high-risk" of promoting resistance as well as to assess the probability of success or failure of future resistance management strategies. As DNA testing and the more traditional resistance bioassays have complementary advantages and limitations,it will be most effective to apply both techniques in a program for resistance monitoring