Dutch elm disease, which has destroyed more than 20 million trees across Britain in the past 30 years, may have met its own nemesis.
Scientists at the University of Abertay in Dundee have created a batch of genetically modified elms that are resistant to the fungus, which brings certain death to the hardwood trees. They claim that their "ground-breaking initiative" could lead to elm trees being re-introduced into their native habitats.
"This is an example of environmentally friendly biotechnology," said Professor Kevan Gartland, the head of molecular and life sciences at the university. "This work could help tackle damaged landscapes and ecosystems blighted by tree fungal diseases, such as Dutch elm disease and chestnut blight, throughout the world."
Elm trees, of which more than 40 species exist, first appeared about 40 million years ago and can live for up to 300 years. But since 1970, more than 20 million have fallen victim in the UK while, over the past 70 years, more than 70 per cent of mature elms in the United States have died.
However, a team of eight scientists at Abertay has found that anti-fungal genes transferred into the elm genome could give the trees the capacity to fight off the killer fungus.
The fungus that causes Dutch elm disease is carried by elm bark beetles which, as their name suggests, breed under a tree's outer bark. The fungus quickly spreads through the tree, preventing water and nutrients from reaching the branches and leaves. Once this diseased stage takes hold, trees can die within weeks. So far, experiments to try to halt the disease using traditional plant-breeding methods have failed.
"The Abertay discovery marks the culmination of a decade's work in the forest biotechnology area," Professor Gartland said. "It's all down to hard work, perseverance and a bit of ingenuity. We used two methods to transfer the genes into the elm genome: through the use of agrobacterium – nature's own genetic engineer – and by firing minute DNA-coated ball-bearings at elm-leaf pieces using a helium-powered gun. Both methods produced good results; some of the trees have reached one and a half metres in height already."
As yet, all of Abertay's genetically modified English elms have been cultivated under strict laboratory conditions and have not been released into the environment. Professor Gartland said: "When the time is right, the trees will undergo rigorous testing in an effort to establish their resistance to Ophiostoma-novo-ulmi, the Dutch elm disease fungus."
A spokesman for the Forestry Commission, which has been funding the project since 1992, said yesterday: "Much of the devastation over the last 30 years has been caused by a mutated and highly virulent strain of Dutch elm disease which we believe orginated in north America.
"We are obviously watching the Abertay project with great interest but there is no possibility as yet of these trees being released into the environment. Our policy is that nothing should be released into the ecosystem until we are satisfied that it is safe to do so and that it would be a significant advantage to forestry. At the same time, we don't want to close our minds to the advantages that this technology could bring."
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