Mite Genomics, a Detoxification Story

Plants produce a wide range of secondary metabolites to defend themselves against herbivore attacks, and generalist herbivores have evolved mechanisms to avoid, sequester or detoxify a broad spectrum of natural defense compounds. Successful arthropod pests have also developed resistance to diverse classes of pesticides and this adaptation is of critical importance to agriculture. The two-spotted spider mite, Tetranychus urticae, an extreme polyphagous pest with more than 1,100 documented hosts, has an extraordinary ability to develop pesticide resistance.

Besides T.urticae, we sequenced and annotated also T.evansi and T.lintearius, resp. a oligophage and a monophage, with the aim at elucidating these differences in feeding habits.

Furthermore, the chelicerate reference genome T.urticaeunderwent further finishing involving optical mapping to assemble the scaffolds further to chromosome scale sequences.

Indeed, from our results it became clear that we need high quality assemblies to be able to pinpoint genes belonging to known detoxification families (like P450, monooxygenases) but also new gene families not previously associated with detoxification in other herbivores, including ring splitting dioxygenase genes acquired by horizontal gene transfer in T.urticae.

From our comparative studies, we could show that, although the 3 mites originated from different parts of the globe, high levels of similarity and even synteny could be observed. These features opens possibilities allowing us to mine for difference in gene content, gene-family size, etc.