Scientists from Ghent University and VIB (The Flemisch Institute for
Biotechnology) have demonstrated how nematodes, also known as roundworms,
manipulate the transport of the plant hormone auxin in order to force the
plant to produce food for them. Their findings, published January 16 in the
open-access journal PLoS Pathogens, could open up new possibilities for the
development of nematode-resistant plants.

Typical symptoms of a nematode infection in plants are withering, seriously
retarded growth, and impaired development of flower and fruit; severely
infected plants often do not survive the damage. Each year, plant-parasitic
roundworms cause more than 80 billion euro in agricultural losses worldwide.

Some 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 nutrients and
water. The roundworms inject a protein cocktail into a single plant cell of
the vascular bundle system, causing the plant cell to merge with neighboring
cells and start producing food for the worm. This plant cell - which can
become as large as 200 normal plant cells - is called the "nematode feeding
site."

In this study, Wim Grunewald and his colleagues demonstrate that roundworms
mislead the plant by disrupting its hormonal regulation. The plant hormone
auxin, important for most plant 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. Grunewald's team
studied the role of plant PIN proteins, which enable auxin transport, and
show that nematodes knock out certain PIN proteins and activate others in
order to establish and develop the nematode feeding sites.

This discovery advances our understanding of how nematodes feed themselves
through plants, and it may lead to ways to thwart these worms in crops -
such as by locally counteracting the nematodes' manipulation of auxin
transport.

Link to the published article:
[dx.plos.org]

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