New research to decode the genetic secrets of prolific potato pest

The full weight of a consortium of world-leading scientists – including those who helped decode the entire human genome – is being thrown at a parasitic worm less than 1mm long.

The potato cyst nematode (PCN), Globodera pallida, attacks potato crops all over the world and is particularly devastating in developing countries where the potato is a subsistence crop. A £1.7 million project led by the University of Leeds to fully sequence its DNA, hopes to shed light on the mechanisms that make the tiny worm such a successful parasite – and lead to methods to sustainably manage this pest.

The research, funded by the Biotechnology and Biological Sciences Research Council (BBSRC), draws together experts from the University of Leeds, the Wellcome Trust Sanger Institute, Rothamsted Research and SCRI, Scotland’s leading centre for crop research.

“Although there is partial resistance in some potato varieties, it is very difficult to breed this resistance into commercial ones - so we’re tackling the problem from a different perspective,” says Dr Peter Urwin from Leeds’ Faculty of Biological Sciences. “If we can find out exactly how this worm works so efficiently, it should lead to measures that will help the potato plant to withstand attack.”

The worm invades the roots of the potato plant and injects a substance causing the plant to create a unique cell from which it feeds via a specialised tube. By doing this, the nematode stunts root growth and deprives the potato plant of essential nutrients, which leads to lower quality, smaller crops.

Says Dr Urwin: “This tiny parasite has evolved many clever mechanisms that we hope to be able to understand more fully through this research. We have no idea what this injected substance is or how it manages to persuade the plant to create the feeding cell. In addition, its eggs can remain viable in the soil for up to twenty years, with hatching triggered by sensing chemicals released by potato roots nearby. Because of this, once a field is infected, it’s almost impossible to get rid of them.”

G. pallida is an international problem, affecting the world’s two major potato growing regions – the Ukraine and Idaho, USA – as well as 18 countries in the EU and 55 countries world wide. The widespread cultivation of potato varieties such as Maris Piper, which whilst naturally resistant to other PCNs, are not resistant to G. pallida, suggests that the significance of the worm is likely to increase.

UK farmers spend in excess of £50 million a year in efforts to manage the pest. Infestations are currently treated with toxic chemicals, which do not enter the food chain, but are expensive to apply and can make soil sterile, killing other living organisms within it.

Dr Urwin says that controlling G. pallida is essential to maintain the competitiveness of UK potato industry, which together with processing and retail markets is worth some £3 billion per year. “We think that consumers are more likely to support UK production that avoids pesticide residues and environmental harm and that is soundly based on a sustainable approach,” he says.

The team hope to complete the sequencing by 2012.

Source: University of Leeds

Related stories:

Research about plant viruses could lead to new ways to improve crop yields
(PhysOrg.com) -- An interdisciplinary group of scientists has obtained the first detailed information about the structure of the most destructive group of plant viruses known: flexible filamentous viruses.
Insight into the evolution of parasitism
Scientists at the Max Planck Institute for Developmental Biology, together with American colleagues, have decoded the genome of the Pristionchus pacificus nematode, thereby gaining insight into the evolution of parasitism. In their work, which has been published in the latest edition of Nature Genetics, the scientists from Professor Ralf J. Sommer's department in Tübingen have shown that the genome of the nematode consists of a surprisingly large number of genes, some of which have unexpected functions.
Scientists behind 'doomsday seed vault' ready the world's crops for climate change
As climate change is credited as one of the main drivers behind soaring food prices, the Global Crop Diversity Trust is undertaking a major effort to search crop collections—from Azerbaijan to Nigeria—for the traits that could arm agriculture against the impact of future changes. Traits, such as drought resistance in wheat, or salinity tolerance in potato, will become essential as crops around the world have to adapt to new climate conditions.
How plants fine tune their natural chemical defenses
Even closely related plants produce their own natural chemical cocktails, each set uniquely adapted to the individual plant's specific habitat. Comparing anti-fungals produced by tobacco and henbane, researchers at the Salk Institute for Biological Studies discovered that only a few mutations in a key enzyme are enough to shift the whole output to an entirely new product mixture. Making fewer changes led to a mixture of henbane and tobacco-specific molecules and even so-called "chemical hybrids," explaining how plants can tinker with their natural chemical factories and adjust their product line to a changing environment without shutting down intracellular chemical factories completely.
Graduate student discovers, names bacterium linked to psyllid yellows
To make a discovery and get to name it is just about every scientist's dream. For one graduate student at UC Riverside that dream already has come true.
Aphids are sentinels of climate change
Aphids are emerging as sentinels of climate change, researchers at BBSRC-supported Rothamsted Research have shown. One of the UK's most damaging aphids - the peach-potato aphid (Myzus persicae) - has been found to be flying two weeks earlier for every 1°C rise in mean temperature for January and February combined.
Key to virulence protein entry into host cells discovered
Researchers from the Virginia Bioinformatics Institute (VBI) at Virginia Tech have identified the region of a large family of virulence proteins in oomycete plant pathogens that enables the proteins to enter the cells of their hosts. The protein region contains the amino acid sequence motifs RXLR and dEER and has the ability to carry the virulence proteins across the membrane surrounding plant cells without any additional machinery from the pathogen.
'Green' potato health risk can be eliminated by cutting away affected area
Potatoes that have turned 'green' can potentially contain a naturally occurring toxin called Glycoalkaloids (GA) and pose a risk to public health according to a review paper published in the latest online issue of SCI's Journal of the Science of Food and Agriculture (JSFA).

News discussion:

General Science news