Ghent, Belgium
January 13, 2009
Scientists from
Ghent University and
VIB have succeeded in showing
how nematodes are able to manipulate the transport of the plant
hormone auxin in order to force the plant to produce food for
them. This advancement in knowledge about this process opens new
possibilities for the development of nematode-resistant plants.
Nematodes
Nematodes are small worms. Some species are plant-parasitic and
infect plants including important agricultural crops. The
typical symptoms of a nematode-infection are withering,
seriously retarded growth, and impaired development of flower
and fruit. Severely infected plants often do not survive the
damage that the worms inflict. Each year, plant-parasitic
nematodes cause more than 80 billion euro in agricultural losses
worldwide.
Plant roots as food factories
Some of these nematodes have developed an ingenious way of
making a plant feed them. They penetrate the plant’s roots and
make their way to their host’s vascular bundles, which are part
of the plant’s transport system for water, minerals, sugars, and
other nutrients. The nematodes select a single plant cell in the
vascular bundle system and then inject this cell with a cocktail
of proteins. The activating influence of these proteins causes
the plant cell to merge with neighboring cells and to start
producing food for the nematode. This plant cell − which can
become as large as 200 normal plant cells − is called the
nematode feeding site.
Nematodes trick the plant
Research has revealed that nematodes mislead the plant by
disrupting its hormonal regulation. The plant hormone auxin,
which is important for nearly every one of the plant’s
developmental processes, accumulates at the site of infection.
Later, when the feeding site needs to grow, auxin accumulates in
the neighboring plant cells. Until now, scientists have not
known how nematodes manipulate the transport of auxin.
PIN proteins
Wim Grunewald and his colleagues from VIB and Ghent University
have been studying the role of PIN proteins in a popular model
plant: the mouse ear cress (Arabidopsis thaliana). These plant
proteins enable the transport of auxin from one cell to another.
To discover the specific function of the various PIN proteins,
the researchers have used plants that, through manipulation, are
not able to produce PIN1, PIN2, PIN3, PIN4 or PIN7. In this way,
the researchers have been able to show that nematodes knock out
certain of the plant’s PIN proteins, while other PIN proteins
are activated just to transport auxin to the neighboring cells.
With this discovery, the scientists are taking us a step closer
towards fully understanding the way in which nematodes feed
themselves through plants. Ways to thwart the nematodes can then
be invented − for example, by locally counteracting the
nematodes’ manipulation of auxin transport. Because current
methods for protecting agricultural and other crops against
nematodes require substances that are very environmentally
unfriendly, this finding can lead to important improvements in
combating this costly problem.
Relevant scientific publication
This research appears in the authoritative journal PloS
Pathogens (Grunewald et al., Plant-parasitic nematodes
manipulate PIN-mediated auxin transport to facilitate
infection).
Funding
This research has been funded by: Ghent University, FWO and VIB.
VIB is a non-profit research institute in the life sciences.
Some 1100 scientists and technicians conduct strategic basic
research on the molecular mechanisms that control the
functioning of the human body, plants, and micro-organisms.
Through a close partnership with four Flemish universities −
Ghent University, the Katholieke Universiteit Leuven, the
University of Antwerp, and the Vrije Universiteit Brussel − and
a solid investment program, VIB unites the forces of 65 research
groups in a single institute. Their research aims at
fundamentally extending the frontiers of our knowledge. Through
its technology transfer activities, VIB strives to convert the
research results into products for the benefit of consumers and
patients. VIB also develops and distributes a broad range of
scientifically substantiated information about all aspects of
biotechnology. More info at:
www.vib.be.
With over 30,000 students, Ghent University (UGent) is one of
the largest universities in the Dutch-speaking world. The
university’s educational offering encompasses virtually all of
the academic fields of study established in Flanders. UGent
prides itself on being an open, socially engaged and pluralistic
university in an international context. More info at:
www.ugent.be. |
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