Transcriptional changes in wheat exposed to wheat curl mite herbivory

Wheat curl mites, Aceria tosichella Keifer, are the most injurious pests of wheat (Triticum aestivum L.). The main injury stemming from wheat curl mite is indirect, and viruses associated with this pest and transmitted to wheat account for millions of dollars in losses to wheat crop each year. Wheat varieties resistant to wheat curl mites and viruses they transmit have been employed successfully in crop production, but their resistance to the vector and associated viruses is often incomplete, and the mechanisms underlying resistance are not known. In fact, little is known regarding the molecular-level interactions between wheat curl mites and their host plants. Thus, the goal of this work was to explore the consequences of wheat curl mite herbivory to wheat resistant to the mites (TAM112) using RNASeq technology and compare it to transcriptional changes in a susceptible wheat variety (Karl 93). We hypothesized that resistant wheat fed upon by wheat curl mites would exhibit a suite of gene expression changes, particularly in its defense-related pathways. We found that resistant wheat unregulated a number of genes and pathways responsible for herbivore and pathogen responses in plants, while these changes were absent in wheat susceptible to the mites. This is the first study to quantify transcriptome-level responses to wheat curl mite in wheat.