Root-knot worm meets its match.

A microscopic worm that slashes the yields of a wide range of food crops may have met its match in a transgenic plant that stops the parasite in its tracks.

Scientists at the University of Georgia created a library of genes from the root-knot nematode to search for unique ones that the parasite requires to infect its host. The researchers honed in on one specific gene, 16D10, that was highly conserved across the four most common species of the root-knot nematode.

Blocking the expression of this gene in the humble Arabidopsis model plant species produced transgenic plants with 95-98% resistance to the root-knot nematode.

Dick Hussey, who led the group, commented, 'I can't think of a single agricultural species that isn't affected by this parasite which is what makes it so interesting.'

Root-knot nematodes infect around 2000 different species of plant. Infestation can lead to losses of 45% in carrot crops and a 70% reduction in bulk weight of onions. New treatments to control the worms are desperately as many nematicides are no longer available and others, such as Telone, will be phased out by the European Commission by 2009.

Hussey is currently using the technology to develop a transgenic soya bean and has approached biotechnology companies with his idea, but has been unable to find a partner. He says that biotech companies appear more interested in developing their own systems so that they own the intellectual property rights.

[ILLUSTRATION OMITTED]

The group became interested in the 16D10 gene because plants are known to use small peptides as signalling molecules.