Intra-diol ring cleaving dioxygenases in Tetranychus urticae: a new family ofdetoxification enzymes in Arthropods ?

All living organisms are exposed to potentially harmful compounds which they can only survive if these compounds are detoxified rapidly. For arthropods, the ability to metabolize plant toxins is considered as one of the major weapons in their co-evolutionary U+2018arms raceU+2019 with plants. However, similar defense mechanisms are applied to cope with pesticides that protect our crops from pests. Amongst arthropods, the two-spotted spider
mite Tetranychus urticae is notorious for its broad host plant range and ability to develop resistance towards pesticides. We have discovered a family of aromatic ring cleaving intra-diol dioxygenases (ID-RCD) in the recently sequenced genome of T. urticae, that were previously unreported in Metazoan genomes. These enzymes allow bacteria and fungi to detoxify aromatic plant defense molecules and man-made environmental pollutants. The projects aims to study the role of ID-RCDs in spider mite physiology, and potentially xenobiotic detoxification in specific. We will compare gene expression profiles of susceptible and pesticide resistant strains and study the effect of ingested plant defense molecules on ID-RCD gene expression. Next, their role will be studied by RNAi and representative genes which will be functionally expressed to study substrate specificity and potentially their interactions with toxins. Finally, we will localize ID-RCD expression in the mite body by in situ hybridization and immunolocalization.