Molecular mechanisms of gene expression variation associated with resistance in a polyphagous pest

Spider mites are important crop pests that can mount a strong transcriptional response when challenged with a novel host, or after adaptation to acaricides. Resistance is therefore a worldwide serious problem. However, gene regulatory mechanisms underlying this plasticity and adaptation potential are not well studied. We have started to unravel the global architecture of gene expression variation in these generalist herbivores.  An eQTL analysis revealed that a single trans eQTL hotspot controlled large differences in the expression of a subset of genes in different detoxification gene families. Additional genetic approaches identified  a duplicated HR96-related gene as causal for the expression differences between strains. The presence of a large family of HR96-related genes in T. urticae may enable modular control of detoxification and facilitating this species’ known and rapid evolution to diverse pesticides and host plants.