Scientists have grown the world’s first genetically modified elm trees. The achievement could lead to the reintroduction into their natural habitat of elm trees resistant to the Dutch elm disease (DED) fungus.
A team of scientists from the University of Abertay Dundee in Scotland performed the groundbreaking work.
Since 1970, more than 20 million elms in the UK have fallen victim to the environmentally devastating disease while, over the past 70 years, more than 70 per cent of US mature elms have been destroyed by DED.
By transferring anti-fungal genes into the elm genome, Abertay researchers have produced genetically modified elms that could fight off the killer DED fungus, which rapidly spreads through infected trees. Their work is published in the August 2001 edition of the academic journal, The Biochemist.
Professor Kevan Gartland is Head of the Division of Molecular and Life Sciences within the University of Abertay Dundee’s School of Science and Engineering and leads the eight-strong research team behind the development.
He said, “This is an example of environmentally-friendly biotechnology. Our work on elm trees could be used to tackle the damage to landscapes and ecosystems caused by tree fungal diseases, such as Dutch elm disease and chestnut blight, throughout the world.”
First studied in Holland, Dutch elm disease is carried by elm bark beetles, which breed under the bark of elms. After the disease is contracted, fungal growth spreads throughout the tree, preventing water and minerals from reaching the branches and leaves. The tree can take weeks or years to die.
Traditional plant breeding approaches to the problems of Dutch elm disease in Europe have failed, and non-GM biotechnological methods have enjoyed only limited success.
Since 1992, the project has been funded by the UK Forestry Commission, which is keen to restore elms to the British landscape where all other efforts have failed.
The Abertay team’s recent discovery marks the culmination of a decade’s work in the forest biotechnology area, according to Professor Gartland.
He explained, “It’s all down to hard work, perseverance and a bit of ingenuity. We used two methods to transfer 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 meters in height already. 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.”
Elm trees first appeared around 40 million years ago and can live for up to 300 years. There are at least 40 different species. Elms are highly valued as shade and amenity trees in the UK and US. They are highly prized for their beauty in the landscape and their ability to withstand environmental stresses in the urban environment.
The remaining seven million US urban elms are worth around $19 billion -- $2,900 per tree. English elms make a particularly good candidate for GM technology because they do not regenerate by seed in the UK.
The Washington and Boston elms are famous cultural symbols in the US, being associated with significant treaties and the American War of Independence. Over the past 80 years, more than 300 million elms have been destroyed by Dutch elm disease throughout the Northern Hemisphere and New Zealand.
Abertay’s GM English elms are being developed under strict laboratory conditions and have not been released into the environment.
(Reference: The Biochemist, August 2001)