The tiny two-spotted spider mite (Tetranychus urticae) causes much anxiety for farmers, and has been, to date, a scientific mystery. It feeds on over 1,100 species of plants, including 150 greenhouse plants and crops, such as maize, soy, tomatoes and citrus.
The cost of chemically controlling damage caused by the spider mite exceeds USD 1 billion per year. In the latest issue of the journal Nature, a multinational consortium of scientists publish the sequenced genome of the spider mite, revealing how it is capable of such feeding frenzy, as well as other secrets of this tiny pest. These findings open the door to new approaches in pest control and crop protection, by allowing greater insight into the biological interactions between plants and herbivores that feed on them.
Élio Sucena and Sara Magalhães, group leaders at the Instituto Gulbenkian de Ciência (IGC) and the Centre for Environmental Biology, University of Lisbon (Portugal), respectively, are part of the 55-strong team of researchers from 10 countries that were involved in this project. Led by Miodrag Grbic (University of Western Ontario, Canada), this team analysed the genome of the spider mite, sequenced with funds from the US Department of Energy (DOE) Joint Genome Institute (JGI) programme, Genome Canada and the European Union.
The spider mite feeds on an astonishingly large number of plants because it withstands the toxins that plants produce. This in itself is an amazing feat. However, among arthropods (animals with exoskeletons, such as spiders, ticks, crustaceans and insects), the spider mite holds first place in the number of pesticides it is resistant to. Mites become resistant to new pesticides within two to four years, meaning that control of multi-resistant spider mites has become increasingly difficult.
Having the sequence of the spider mite genome has shown light on the genetic basis for its feeding flexibility and pesticide resistance. The secret lies in having, on the one hand, more copies of the genes involved in digesting and degrading plant toxins when compared to insects. On the other, the tiny pest seems to have incorporated genes from bacteria and fungi that are involved in digestion and detoxification.
Indeed, the researchers identified two groups of bacterial and fungi genes that are unique to the spider mite, suggesting that the tiny arthropod is adept at making the most of the innovation of transfer of genes between distant species (called lateral gene transfer - a rare occurrence in nature).
Other groups of genes are shared, with aphids, for example (aphids are insects that also feed on crops). By comparing the aphid genome with that of the spider mite, it seems that the bacterial genes moved first into the insects and from these were taken up by the spider mite.
The name gives it away: spider mites make webs, for protection against predators and as a barrier against bad weather. However, their webs are different to those made by spiders: the genome sequence has revealed 17 genes involved in making web proteins. These proteins make thinner fibres, but seem to be slightly more resistant to mechanical forces than other natural materials.
All these secrets came out of a very small genome - only 90 megabases (the fruit fly genome has 180 megabases; the human genome has 3,000 megabases). It is, indeed, the smallest arthropod genome sequenced so far, and reveals a remarkable evolutionary history: the spider mite has lost many genes that are shared amongst arthropods, but has accumulated species-specific genes, such as those that give it the ability to withstand toxins and pesticides.
The Portuguese scientists were involved in analysing immunity-related genes found in the spider mite genome. The spider mite belongs to the Chelicerata family, the second largest group of terrestrial animals. Chelicerates include spiders, scorpions and ticks. Chelicerates and insects make up the Arthropods. The spider mite is the first chelicerate to have its entire genome sequenced and analysed.
Ana Godinho | EurekAlert!
Forest Management Yields Higher Productivity through Biodiversity
14.10.2016 | Technische Universität München
Farming with forests
23.09.2016 | University of Illinois College of Agricultural, Consumer and Environmental Sciences (ACES)
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.
In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...
'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.
Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
21.10.2016 | Health and Medicine
21.10.2016 | Information Technology
21.10.2016 | Materials Sciences