"Aphids are worldwide a serious pest on many plants, including important crops. The species Arabidopsis thaliana displays a large amount of natural genetic variation in resistance against the green peach aphid Myzus persicae. This project will exploit this natural genetic variation for mapping of quantitative trait loci (QTL) for Myzus resistance in publicly available Arabidopsis recombinant inbred lines, with a subsequent characterization of the causal genes. The objectives of the proposed project are (i) fine-mapping of one (or more) resistance QTL, (ii) cloning of the underlying genes, (iii) understanding of the mechanistic role of these genes and their gene products in defense against aphids, and (iv) decoding of the evolutionary trajectory of these genes by analyzing patterns of nucleotide variation within Arabidopsis thaliana and among close and distant Arabidopsis relatives. This project will lead to new insights into plant-insect interactions in general and plant-aphid interactions in particular, not only from a functional but also from an evolutionary perspective. It will help to dissect the genetic basis of plant resistance against aphids and will open up new perspectives for sustainable agriculture."