Genetic code of first arachnid cracked

An international team of scientists - including Ghent VIB scientists - has succeeded in deciphering the genome of the spider mite. This is also the first known genome of an arachnid. This premiere not only brings along new insights into the evolution of arthropods, but also offers new opportunities to develop means of crop protection against the spider mite.

Spider mites, house dust mites and ticks

Spider mites belong to the group of the Acari (among arachnids) and are related to dust mites and other parasitic mites such as ticks that transmit serious diseases to humans and animals. (http://www.acari.be/)

Enormous damage to many crops

Spider mites are colonial, invasive mites that feed on plant juices. The spider mite Tetranychus urticae likes over 1100 different plant species and is a real plague in ornamental gardens and in greenhouse cultivation in our regions, among which, tomatoes, peppers, cucumbers, strawberries, or complete corn and soybean fields.

Spider mites pierce plant cells of the leaves and suck them dry. On most plants, spider mite damage can be recognized as small yellow spots on leaves. Spider mite pests lead to reduced harvests for farmers and are a threat to food production. In severe attacks, the leaves, or even entire plants, wither and die. Spider mites got their name from their ability to make silk threads which they wrap around plants.

The annual cost of pesticides against spider mites amounts to 0.5 to 1 billion dollars and scientists predict that due to global warming, spider mite plagues will increase. Furthermore, the spider mites are known to show resistance to different kinds of pesticides and the current study of the genome will shed light on the mechanisms present in the mite to develop fast adaptation and resistance.

Genome reveals unique characteristics

Stephane Rombauts, Pierre Rouze and other colleagues from the research team of Yves Van de Peer were part of the international team that mapped the genome of T. urticae. This genome contains unique genes that have not been identified in other arthropods. These new genes play an important role in the development of spider mites during evolution. The researchers identified numerous genes - involved in detoxification and digestion - which help to explain the unsurpassed resistance of spider mites to pesticides and his polyphagy. New genes were also identified that are responsible for the production of silk threads by the spider mite. With this knowledge, scientists can try to reproduce this nanomaterial and possibly this new material may then be used in medical biotechnology. The unique combination of properties that can be found in silk threads - including particularly strong, not too elastic elastic and shock resistant - can hardly be found in any other type of material.

Source : VIB (the Flanders Institute for Biotechnology)