Leeds, United Kingdom
November 28, 2007
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 (1). “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.
(1) Figures cited from the British Potato Council
BACKGROUND
1. Parasitic worms cause disease in plants, animals and humans.
This new initiative from the BBSRC expands the scope of an
international effort to use genome technology to help understand
these poorly understood pathogens. The activities of the four
partners will be as follows: the Leeds group will lead the
research; SCRI will focus on genes involved in the parasitic
process of the nematode; Rothamsted Research will use the genome
information to develop studies on natural enemies of PCNs and
the Wellcome Trust Sanger Institute will develop comparative
studies with other parasitic nematodes.
2. The most economically important species of potato cyst
nematodes are Globodera rostochiensis and Globodera pallida. G.
rostochiensis has been largely managed in the UK through the
development of the popular Maris Piper potato, a strain of
potato which is naturally resistant to it. There is no
comparable, natural resistance gene for G. pallida, which
devastates potato crops around the world – including Maris Piper
crops. Infested soil is currently treated with toxic chemicals,
such as astelone, which do not enter the food chain, but are
expensive to apply and are harmful to the environment.
3. Dr Peter Urwin is part of the internationally renowned Plant
Nematology Lab of the Centre for Plant Sciences at the
University of Leeds. The lab works on improving fundamental
knowledge of plant nematodes and the development of technologies
to be used in managing problematic species for which it holds 7
patents with a further 5 pending. Dr Urwin’s work is
specifically linked to agricultural plant nematodes and he has
expertise in those affecting potato, rice and banana crops.
4. The University of Leeds’ Faculty of Biological Sciences is
one of the largest in the UK, with over 150 academic staff and
over 400 postdoctoral fellows and postgraduate students. The
Faculty has been awarded research grants totalling some £60M and
funders include charities, research councils, the European Union
and industry. Each of the major units in the Faculty has the
highest Grade 5 rated research according to the last government
(HEFCE) Research Assessment Exercise, denoting research of
international standing. The Faculty is also consistently within
the top three for funding from the government’s research
councils, the BBSRC and NERC. www.fbs.leeds.ac.uk
5. The Wellcome Trust Sanger Institute is one of the world's
leading genome sequencing centres. As well as being a leading
partner in the Human Genome Project sequencing one-third of the
human genome sequence, the Institute participates in national
and international projects to sequence the genomes of
disease-causing organisms. Currently, it is sequencing or
analysing the genomes of some 40 organisms. The Institute
employs nearly 600 people in the purpose-built campus at
Hinxton, near Cambridge, UK. http://www.sanger.ac.uk
6. Rothamsted Research is based in Hertfordshire and is one of
the largest agricultural research institutes in the country. It
is sponsored by the Biotechnology and Biological Sciences
Research Council (BBSRC). Prof Brian Kerry leads the Nematode
Interactions Unit, which is focused on the interactions between
nematodes and their plant hosts and the microbial community in
the rhizosphere. The research has produced two patents for
compounds that affect the behaviour of nematodes in the
rhizosphere and reduce root invasion and has led to the
development of a biological control product for use against
root-knot nematodes in tropical soils. (www.rothamsted.ac.uk).
7. SCRI is an internationally renowned centre for crop research
based at Invergowrie on the banks of the Firth of Tay in
Scotland. It employs more than 300 staff. It has expertise in
barley, soft fruits and potatoes: it hosts the Commonwealth
Potato Collection. The four, main science programmes are
Environment Plant Interactions, Genetics, Plant Pathology and
Food Quality, Health and Nutrition. SCRI has a history of
breeding for PCN resistance. The Pathology group has a strong
record in the study of host-parasite interactions. The knowledge
that comes from SCRI’s research programmes informs the policies
of the Scottish Government. The senior staff are also active in
UK and European agencies. SCRI has a commercial subsidiary,
Mylnefield Research Services, which mediates partnerships with
business to develop innovative products. www.scri.ac.uk |
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