Ash trees

Scientists discover genetic basis of resistance to ash tree dieback

New research has uncovered the genetic basis of resistance to ash dieback, which may help in the battle against the disease in this country

A new study, researched by scientists from Queen Mary University of London and the Royal Botanic Gardens, Kew, offers hope in the battle to protect the UK’s trees against ash dieback.

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The genetic basis of resistance to ash dieback in UK trees has been identified, which opens up new conservation avenues.

Researchers from both institutions sequenced DNA from over 1,250 ash trees to find inherited genes associated with ash dieback resistance. Results shows that resistance is controlled by multiple genes, which suggests that surviving trees could be used to restore diseased woodlands, by natural regeneration or selective breeding.

The study was published in journal Nature Ecology and Evolution, and offers hope to arboretums and tree experts across the UK.

Silk Wood in autumn, Westonbirt Arboretum,
© Anne Gilbert/Alamy

Professor Richard Nichols, author of the study, said: “We found that the genetics behind ash dieback resistance resembled other characteristics like human height, where the trait is controlled by many different genes working together, rather than one specific gene.”

“Now we have established which genes are important for resistance we can predict which trees will survive ash dieback. This will help identify susceptible trees that need to be removed from woodlands, and provide the foundations for breeding more resistant trees in future.”

The research involved collecting samples from ash trees in a Forest Research mass screening trial, which comprises 150,000 trees planted across 14 sites in south east England. Many genes associated with ash dieback resistance were similar to those previously shown to be involved in disease or pathogen responses in other species.

According to the Woodland Trust, Hymenoscyphus fraxineus, which was first scientifically described in 2006 under the name Chalara faxinea, will affect 95 per cent of ash trees across the UK. It can affect trees of all ages and symptoms include leaves developing dark patches in summer that wilt and discolour to black, shoots and leaves dying back, which is visible in summer, lesions where branches meet the trunk and new growth from previously dormant buds further down the trunk (a common response to stress in trees).

It is expected to cost the British economy £7.6 billion over the next 10 years.

Professor Richard Buggs, senior research leader in plant health at the Royal Botanic Gardens, Kew, and author of the paper said: “Ash dieback threatens to kill over half of the 90 million ash trees in the UK. This will have a huge impact on the British landscape. Our new findings will help us to predict how ash populations will evolve under ash dieback.”

“While many ash trees will die, our findings are encouraging from a long-term perspective and reassure us that ash woodlands will one day flourish again.”

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Westonbirt Arboretum recently announced that it would be working on a major project to replace diseased ash trees in its ancient Silk Wood.