Western researchers lead sequencing of genome for second-largest group of animals

London, ON – An international consortium led by a researcher at The University of Western Ontario has unveiled the first genome of the second-largest group of animals on Earth: Chelicerates. 

Western’s Miodrag Grbić and a research team featuring scientists from Spain, Belgium, France, Portugal, USA, Chile, Germany and Switzerland have sequenced the genome of the spider mite, Tetranychus urticae, which is one of the world’s most cosmopolitan agricultural pests.

Feeding on more than 1,000 different plants – including 150 of agricultural importance, such as maize, soy, strawberries, tomatoes, cucumbers and peppers – the spider mite causes damages that approaches $1 billion annually. Insects and mites currently destroy 13 per cent of all potential crops.

“We have discovered this creature’s gene set and more importantly, we believe we have found its Achilles heel so that we can begin development of non-pesticide, alternative pest control measures,” says Grbić, a biology professor in Western’s Faculty of Science. “This species is renowned for developing resistance to pesticides. Within two years of introduction, spider mites are able to overcome new pesticides.” 

The scientific team uncovered the genetic basis for mites’ ability to feed on many different plants, discovering that the spider mite is able to multiply and evolve new genes to detoxify toxic plant molecules and – most surprisingly – also ‘hijacks’ detoxification genes from bacteria, fungi and plants to combat the plant defences before incorporating them into its own genome.

Miodrag Grbić

By identifying genes that allow us to breed plants resistant to spider mites, introduce new tools for biotechnology-based pest controls and reduce spider mites’ ability to reproduce, this pioneering genomics work opens new avenues for sustainable agriculture. This will result in more pesticide-free food on Canadian tables.

While the spider mite is an important and harmful pest, Grbić’s group, in collaboration with nano-physicists Jeff Hutter at Western and Marisela Velez at Universidad Autonoma de Madrid, also discovered a novel benefit: spider mite silk.

This naturally occurring nanomaterial of extreme lightness has potential uses as a reinforcement in composite materials – including for the automotive and aeronautic industries – nanodevices and nanoprobes for investigating the function of cells, and as a matrix for tissue engineering and drug delivery.

These efforts represent the first complete genome of chelicerates – the second-largest group of animals in the world behind insects – which include spiders, scorpions, horseshoe crabs, ticks and mites.

Published in the latest issue of the prestigious journal, Nature, this work, which was conceived in Grbic’s laboratory at Western in 2000, has been supported by the Natural Sciences and Engineering Research Council of Canada, Genome Canada, the Ontario Genomics Institute, the Ontario Research Fund- Global Leadership in Genomics and Life Sciences program and the USA Department of Energy.

Download high resolution photos

Spider Mite Profile Photo by Thomas Van Leeuwen and Wim Grunewald	Spider Mite Top View
Spider Mite on Tomato Leaf	Spider Mite Silk on Bean Plant
Treated vs Control Plant

For more information, please contact Jeff Renaud, Senior Media Relations Officer, 519-661-2111, ext 85165, jrenaud9@uwo.ca

Spider mites are one of the major pests in agriculture. They feed on more than 1,000 plant species and have rapid development (generation time of 7 days in a hot season). They represent a key pest for greenhouse crops, annual field crops and many horticultural crops. They are widespread in Canada. Spider mites cause yellow flecks on the leaf surface, and upon heavy infestation, leaves become pale, brittle and covered in webbing. This damage can cause severe reduction in yield.