In a major breakthrough in efforts to tackle ash dieback, UK scientists have identified the country’s first ash tree that shows tolerance to ash dieback.
The development raises the possibility of using selective breeding to develop strains of trees that are tolerant to the disease.
The findings, which Defra believes could help ensure ash trees will thrive in UK woodlands, have today been published in a report co-funded by Defra and the Biotechnology and Biological Sciences Research Council (BBSRC).
Ash dieback has been spreading throughout the UK for a number of years, posing a real threat to the future of the species.
The Nornex project, led by the John Innes Centre (JIC) in Norfolk, looked at one heavily infected woodland in Norfolk where, among the many infected trees, there were exceptions which demonstrated very low levels of infection by the ash dieback fungus.
The researchers have identified one tree, nicknamed ‘Betty’, as having a strong tolerance to the disease.
The team compared the genetics of trees with different levels of tolerance to ash dieback disease.
From there, they developed three genetic markers which enabled them to predict whether or not a tree is likely to be tolerant to the disease – even whether it is likely to be ‘mildly’ or ‘strongly’ tolerant.
Betty was predicted to show strong tolerance.
The Nornex report also indicates that the three genetic markers are more prevalent in UK ash trees than in those from some other countries.
Reasons for this are as yet unknown but this could be taken into consideration for any future tree development programmes.
Unveiling the latest findings at the JIC Defra spokesperson in the Lords, Lord Gardiner, said:
“This Government has invested more than any other country in research on ash dieback, and today’s breakthrough is an excellent example of how the UK’s cutting-edge science is leading the way to help support tree health.
“We want to guarantee the graceful ash tree continues to have a place in our environment for centuries to come and this vital work is a major step towards ensuring just that.”
UK Chief Plant Health Officer, Nicola Spence said the development ’paves the way for tackling this destructive disease and will help ensure that Britain’s stock of ash trees, and its countryside, remains resilient against pests and disease in the future’.
Professor Allan Downie, Emeritus Fellow at the JIC and coordinator of the Nornex consortium, said: “The identification of genetic markers for trees with low susceptibility to ash dieback is a large first step, one of many that will be needed in the fight to help ash trees survive this disease epidemic.
“It is astonishing that we have come so far in so short a time, and this success is due to the commitment and collaboration of my many colleagues and the funding they received from BBSRC, Defra and NERC.”
Professor Melanie Welham, BBSRC Chief Executive, said: “Tree pests and pathogens present a significant challenge to our woodlands and habitats, but through fundamental bioscience research we can gain the vital insights needed to help protect the UK’s trees.”
Country Land and Business Association president Ross Murray said: “Ash is one of Britain’s iconic trees and the loss of the ash species would be devastating to the ecology and landscape of our countryside, as well as those woodland owners that rely on ash stock.
“This breakthrough highlights the value of good science in identifying resistant strains and holds the promise that although ash will be a much less common feature of our countryside in the immediate future, there is hope that a more resilient version can be nurtured and be enjoyed by our grandchildren.”
Woodland Trust director of conservation Austin Brady said: “We welcome today’s important news and are ready to help Defra with the task of screening native ash trees across the UK to find resistant or tolerant trees.
"Early indications suggest that the variability in UK ash means we may have more natural resistance in our trees than those on the continent.
“This offers hope to all who value the countryside and our beloved native ash tree, and is a real credit to the expertise of our plant health scientists.
"What is now paramount is the implementation of a thorough recovery plan, using this new knowledge, to start replacing the thousands of trees we will still inevitably lose with a range of our well-loved native species, alongside new strains of ash identified by this ground-breaking screening process.”
“We will need provision of further funding and support and must work to remove barriers which are deterring people from planting more trees, to ensure everyone has an opportunity to prolong the presence of ash in the countryside."
Prof Steve Woodward, Department of Plant and Soil Science, University of Aberdeen, said: "I welcome the report: the work has provided some exciting and very valuable results.
"There is clearly great variation in the extent to which trees are able to 'tolerate' the presence of the pathogen. A rate of 3 per cent of trees showing tolerance doesn't sound high but ash does seed prolifically, of course, so perhaps survivors will eventually fill some of the gaps left by more susceptible individual trees.
"The three genetic markers for tolerance present in a small proportion of ash give a super tool for marker-led selection and breeding."