Population structure and natural selection in the Chalara ash dieback fungus, Hymenoscyphus pseudoalbidus

Lead Research Organisation: John Innes Centre
Department Name: Crop Genetics

Abstract

Chalara ash dieback is a devastating disease of the European ash and has destroyed large numbers of trees in continental Europe and Scandinavia over the last 20 years. It is caused by a fungus, Hymenoscyphus pseudoalbidus, of which the asexual stage is Chalara fraxinea, hence the common name of the disease. It was first identified in the UK in 2012 and has since been found at hundreds of sites throughout Britain and Ireland. The fungus spreads by dispersal of the sexual spores by the wind and by imports of diseased trees.

Ash is a sexual species which reproduces by prolific seed production, so over the course of time, it is very likely that resistance to Chalara will evolve in the UK population by natural selection. An important challenge for forest scientists is to accelerate this process so that the ash population can recover more rapidly, ideally within a few decades. As the behaviour of introduced forest pathogens can be unpredictable, it is important to understand the evolutionary potential of the fungus.

This project will investigate the ecological genetics and evolutionary potential of H. pseudoalbidus, i.e. the way that genetic variation in the fungus is distributed in relation to the natural environment and its capacity to evolve in response to natural selection. We will obtain information about four key aspects of the population biology of the fungus which can be applied to breeding and management of commercial and natural ash populations.

First, we will investigate the distribution of vegetative compatibility (VC) groups in populations of H. pseudoalbidus in the UK. Many fungi use VC as a system of self/non-self recognition so that when genetically different individuals encounter each other, they form barriers between them which largely prevent each individual from invading the territory occupied by the other. Another important feature of VC barriers is that they inhibit fungi from transmitting doubled-stranded RNA viruses to each other. Study of the spatial distribution of VC groups and of the two mating types will allow us to assess the potential for dsRNA viruses to become established in the H. pseudoalbidus population and thus contribute to attenuating the Chalara epidemic.

Second, we will study the spatial distribution of genetic variation in H. pseudoalbidus, as determined by two types of DNA marker. As the fungus appears to be an ecologically obligate pathogen which depends entirely on its host to complete its life cycle, natural selection is most likely to takes place within host tissue. We will estimate levels of genetic diversity in local populations of H. pseudoalbidus and variation between populations. This will enable us to understand how diverse are the populations of the fungus which are dispersed by the wind and on imported trees. We will then investigate genetic diversity within trees at different stages of the life cycle. This will provide insights into the operation of natural selection on the fungus within its host.

Third, we will investigate variation in traits related to pathogenicity and the life-cycle of H. pseudoalbidus. This information is fundamental to understanding the way that natural selection can cause the fungus to evolve in the natural environment. It is also important for breeding resistant ash trees because if a higher level of pathogenicity involves a cost to the fungus in terms of its reproductive fitness, resistance should become established more widely in the population of ash trees.

Lastly, we will investigate the relationship of H. pseudoalbidus to a closely-related fungus, H. albidus, which has known in the UK since the 19th century and is not considered a harmful pathogen. In particular, our research will aim to understand why H. pseudoalbidus is a much more aggressive parasite than H. albidus and what potential there is for dsRNA viruses to be transferred from H. albidus to H. pseudoalbidus, possibly contributing to a decline in the epidemic of Chalara.

Technical Summary

This proposal is to research the ecological genetics and evolutionary potential of Hymenoscyphus pseudoalbidus (Hp), the ascomycete fungus which causes Chalara ash dieback (CAD) of the European ash (Fraxinus excelsior). This disease has destroyed large numbers of trees in continental Europe; it appeared in the UK in 2012 and has spread rapidly. The project will study four key aspects of Hp to provide a sound foundation for research on its population biology and disease management.

1. We will investigate the spatial distribution of vegetative compatibility (VC) groups in populations of Hp in the UK and will research the potential for dsRNA viruses to become established in Hp and thus attenuate the CAD epidemic.

2. We will study the spatial distribution of DNA marker variation in Hp, both within and between local populations and with developed lesions within trees. This will provide insights into the potential for natural selection to influence evolution of the fungus.

3. We will investigate variation in pathogenicity and life-cycle traits in Hp. This will provide insights into the potential for evolution of Hp by via natural selection, including responding to enhanced resistance in ash populations. Also, as coevolutionary theory makes the robust prediction that a higher cost of pathogenicity will lead to stronger selection for host resistance, studies of pathogen variation will allow predictions of the extent to which 'natural' resistance will become established in the ash population and how quickly this will happen.

4. We will investigate the genetic and ecological relationship between Hp and a closely related fungus, H. albidus (Ha), which is a non-pathogenic fungus indigenous to the UK. The research will compare pathogenicity traits in Ha and Hp and, through comparative study of their VC and mating sytems, will assess the potential for any dsRNA viruses to be transmitted between these fungal species.

Planned Impact

Knowledge about populations of Hymenoscyphus pseudoalbidus (Hp) will inform (1) breeding strategies for resistance to Chalara ash dieback (CAD) in commercial ash trees in the UK and elsewhere and (2) management of natural populations of Fraxinus excelsior, the European ash, to promote evolution of resistance to CAD. All four objectives of this project will contribute to this goal.

Diversity in vegetative compatibility (VC) groups (VCG) is an indicator of the likely success of control methods using hypovirulent Hp infected by dsRNA viruses pathogenic to the fungus. The diversity of VCG in ascomycetes is an important determinant of the rate of transmission of deleterious dsRNA. If VC diversity in Hp is low, both across the UK and in local populations, and if each genet in a developed lesion occupies a large volume of wood, it may be possible to consider using hypovirulent Hp to control CAD by transmitting the virus to other genets. This project will therefore provide information about the likely success of attempts to use hypovirulent strains of Hp to limit the severity of outbreaks of CAD.

The project will also provide information relevant to genetic and pathogenic variation in Hp and processes by which new genotypes are generated and dispersed. Such data on pathogen variation are essential in breeding for disease resistance. If new outbreaks are established by genetically diverse populations of Hp originating from sites where CAD is already established, it will be relatively easy to set up trials to select CAD-resistant ash because each trial will be exposed naturally to a wide range of pathogen genotypes. By contrast, if new outbreaks are established by small sub-samples of established populations, it will be necessary to establish many trial sites because data from any one site may not be typical of responses to Hp in general.

Data on fitness costs and trade-offs will indicate the likely success of resistance breeding and releasing resistant germplasm into the natural environment. An important feature of host-parasite coevolution is that variation in the host influences parasite evolution and vice-versa. Specifically, a higher cost of pathogenicity leads to a higher frequency of resistance in the host. If costs of pathogenicity are high, we can rely on natural selection to re-establish resistance to CAD in the wild population of F. excelsior because resistance genes will be reassorted within genomes of the host, which reproduces sexually and disperses prolific amounts of seed. By contrast, if costs are low, it may be necessary to devise other strategies for reviving the native ash population, such as introduction of resistant germplasm from East Asia.

Research on Hymenoscyphus albidus (Ha), a fungus indigenous to the UK which is closely related to Hp, is more speculative but may in the long term be richly rewarding. Ha may be a source of dsRNA viruses capable of mitigating the damage caused by Hp The potential for using Ha as a source of hypovirulence to control Hp requires not only knowledge of dsRNA in Ha but also of ecological and biological interactions between Ha and Hp.

The project will also contribute to the quality of life in the UK (BBSRC Strategic Priority for Lifelong Health and Wellbeing). A public health study (Donovan et al. 2013, Am. J. Preventative Medicine 44:139-145) showed that access to the natural environment, especially woodland, has great benefits in increasing opportunities for exercise and thus for cardiovascular and respiratory health. Indeed, FR has found that one of the main public concerns about CAD and other tree epidemics is the loss of access to woodland for recreation, a common theme in the value that the general public in the UK places on natural forests. As ash represents 13% of broadleaf tree cover in the UK, recovery from this destructive disease will benefit the public by restoring access to woodland and reducing the risk of injury from falling, diseased trees.
 
Title TheAshProject: A Lasting Legacy for the Ash Tree 
Description Artistic walks, talks and workshops 
Type Of Art Performance (Music, Dance, Drama, etc) 
Year Produced 2017 
Impact Producing a major new commission by internationally recognised artists Ackroyd & Harvey plus walks, talks and a programme of workshops, an online archive and a Kent wide plan for landscape restoration in the wake of ash dieback. 
URL http://www.theashproject.org.uk/
 
Description Dieback, a devastating disease of European ash (Fraxinus excelsior), has destroyed many trees in continental Europe and Scandinavia. It was first observed in north-east Europe in 1992 and was detected in the UK in 2012 although analysis of forestry plantings indicates it probably arrived here in the early to mid-1990s. The fungus which causes ash dieback, Hymenoscyphus fraxineus (formerly H. pseudoalbidus, anamorph Chalara fraxinea) is endemic to Far East Asia, where it is a mild pathogen of native Fraxinus species. Although the mode of arrival of the fungus in Europe is not known, the epidemic on European ash may have originated from as few as two sexually compatible fungal genotypes.

Ash is a keystone species in the natural environment throughout the UK and is an important commercial hardwood species; until the arrival of dieback, it was second only to oak as the frequently planted broadleaf tree. As a large, fast-growing deciduous tree, it is also important as an amenity species and provides important ecological services. Recovery of the UK ash population will benefit wildlife, forestry, farming, maintenance of roads and railways, and indeed the general public who use woodlands for exercise and relaxation.

As ash and the dieback fungus both reproduce sexually, there is a high potential for natural selection to act on both species and to cause the interaction between them to evolve. In coevolutionary theory, the long-term outcome will be determined by fitness costs of traits in both partners: of pathogenicity in the fungus and of dieback-resistance in the tree. It is predicted that if these penalties are substantial, ash dieback will lessen in severity after several sexual generations, allowing the UK's woodlands to recover. For this to happen, natural selection must be effective in altering gene frequencies in both plant and fungus. The opportunity for this to happen is greatest if populations are large, mobile and uniform, without much internal subdivision.

In this project, we investigated the ecological genetics of H. fraxineus. Related research on variation in dieback-resistance in F. excelsior from the UK is now in progress. Our overall aim was to investigate the population biology of the pathogen, with a view to understanding and managing ash dieback, and indeed destructive, invasive plant pathogens in general.

We investigated the spatial structure of H. fraxineus populations, to assess the potential for natural selection to operate within fungal populations. Our research combined studies of DNA markers, mating-type genes and virus infection with analysis of vegetative compatibility, a system of self-nonself recognition found in many fungi. Our data were consistent with ash dieback arriving in the UK in two ways. One was as airborne ascospores, the products of sex, which were blown on the wind from continental Europe and infected ash in the east of the UK, including ancient woodlands. The other route was in diseased nursery stock planted throughout the UK. Both modes of arrival made large contributions to the ash dieback epidemic in the UK, both resulted in high genetic diversity in fungal populations, there was little differentiation between the two types of population, and the structure of local populations does not differ from that expected with random mating. The implication for host-parasite coevolution is that a large population size and frequent recombination in H. fraxineus generates high genotypic diversity on which natural selection can act.

We developed the analysis of local variation by investigating the dynamics and structure of H. fraxineus populations within trees. The fungus first infects leaves, then grows through the rachis into the wood. Eventually it reaches boughs and stems, where it causes large cankers which may girdle the bark, killing the tree above the lesion. We showed that an ash tree may be initially infected by hundreds of ascospores or even more, reflected in the very high genetic diversity in fungal populations within leaves and rachises. This indicates a high potential for natural selection during this early stage of infection. The next generation of ascocarps is formed on fallen, infected rachises during the winter and spring, so we also predict that there is a high potential for natural selection during growth, mating and reproduction within the old rachis, followed by spore dispersal.

In research on the indigenous fungus H. albidus, which is a weak pathogen of ash and is closely related to H. fraxineus, we also found high diversity in vegetative compatibility phenotypes. The wide variation in vegetative compatibility in both fungi implies that there is limited potential for viruses to be transmitted between fungal genets, either within H. fraxineus or between H. fraxineus and H. albidus. It is therefore unlikely that virus-infection can be used to attenuate the growth of H. fraxineus and thus control ash dieback, in contrast to the successful exploitation of virus-induced hypovirulence to manage chestnut blight in south-eastern Europe.

In contrast to leaf infections, almost every stem lesion we examined was formed by only one genotype of H. fraxineus. We hypothesise that of the many fungal genets that infect a leaf, those that take the least time to grow from infected leaflets through the rachis and into the bark of shoots and stems are most likely to infect the boughs and trunk. Although stem cankers kill trees, they do not contribute directly to the pathogen population because the fungus within a canker can only reproduce if it somehow manages to infect a rachis. Genes which alter fungal pathogenicity can be subject to natural selection, however, if they also alter reproduction or spore dispersal. We measured a large fitness cost of pathogenicity, implying that there may be an ecological trade-off between the ability to cause disease and the capacity for fungal reproduction. This high penalty of pathogenicity in the fungus means it is likely that resistance genes will be maintained in the host population of F. excelsior.

Viewed together, our results suggest that the most likely long-term outcome of the ash dieback epidemic is that H. fraxineus will persist in Europe as a pathogen of moderate importance, while F. excelsior will evolve to become moderately resistant to dieback. This parallels some other recent epidemics of invasive diseases, such as myxomatosis of rabbits. Even so, we do not know how long it will take for this equilibrium to be reached; a reasonable estimate is a few tens of generations over several hundred years.

As trees are long-lived, their populations take so long to recover from attack by aggressive, invasive parasites, and the costs of responding to devastating epidemics are so high, it is vital to restrict the movement of destructive pathogens, including potentially infected planting stock. A substantial reduction in the distribution of exotic plant species into and around Europe, unless they are known not to be carriers of invasive pests - in accordance with the "precautionary principle" - would help to achieve this.

Further work is in progress to complete experiments begun in this project. Results will be reported in our ResearchFish submission in March 2020.
Exploitation Route Despite recent advances including a complete genome sequence, much of the biology, pathology and ecology of H. fraxineus remains unknown. An question of particular importance for future research and forest management is what variation there is in overall aggressiveness and individual pathogenicity traits in H. fraxineus in its native range, which is thought to cover much of temperate Asia east of the Urals - a vast area. This has important consequences for future disease control (see above: 'Movement of ash plants and wood').

Forest Research continues to investigate the threat that ash dieback presents to the environment including transport corridors and other services in the UK. A student at Forest Research in working on this subject from November 2017 to December 2020, jointly funded by Defra, Network Rail and the Woodland Trust.

An important question which concerns the host, noting that genetic resistance is likely to be the main route to recovery of ash in the UK, is whether or not there will be a significant detrimental effect of selecting strongly for dieback resistance. In a Danish population of F. excelsior, susceptibility to dieback was associated with low levels of iridoid glycosides, compounds which are toxic or deterrent to invertebrate herbivores (Sollars et al., 2017). JIC led a successful bid by a consortium including NIAB East Malling Research and the University of Warwick for BBSRC response-mode funding in April 2018 (BB/R018618/1), to investigate the relationship between the chemical content of ash leaves and bark, resistance to dieback, susceptibility to invertebrates, and tree phenology. This is a multi-disciplinary project involving plant pathology, entomology, genetics, population genetics, ecology, metabolomics and plant molecular biology. It is expected that the results will indicate if there is a significant trade-off between resistances of ash to different pests and pathogens. Forest Research and Norfolk County Council are making an in-kind contribution, valued at approximately £20,000, to the research through provision and management of a field trial site with a deer fence near Acle, Norfolk.

As a resource for the project above and future research on ash, JIC and NIAB-EMR have established a collection of F. excelsior accessions which is strongly enriched for genotypes which show good resistance to dieback in natural situations where most other ash trees nearby are heavily diseased. The population, known as JENNIFER: the John Innes / East Malling National Nursery for Fraxinus excelsior Research, consists of 328 Fraxinus lines, including 324 F. excelsior, which have been replicated by grafting, funded by an extension to the Nornex project. This permits replicated experiments on individual genotypes, and different experiments to be conducted on the same genotype. Two or more ramets of each accession are being maintained at JIC and EMR, while up to six ramets have been planted in a field trial. Further multiplication of the population will be achieved by additional grafting onto rootstocks grown from seed from a disease-free location.

JIC, together with NIAB-EMR is contributing to a current Tools & Resources project at the University of Warwick (BB/B021452/1) to develop improved methods for untargeted metabolite profiling and identification of secondary metabolites in leaves of UK F. excelsior accessions which discriminate between high and low levels of resistance to dieback. The results of this research will feed into BB/R018618/1.

JIC and FR are collaborating with others, including EMR, the Future Trees Trust and the Royal Botanical Gardens Kew, on setting up orchards with resistant F. excelsior germplasm, which can be used as sources of seed or graftwood for future sowing and planting when restrictions on the movement of healthy ash wood and seed within the UK have been lifted.

A further threat to ash trees in the UK is the emerald ash borer, Agrilus planipennis. This beetle, native to East Asia, has caused widespread destruction of native ash species in eastern North America. It is now moving eastwards across Eurasia and has affected F. excelsior as far west as Moscow Oblast in the Russian Federation (Straw et al., 2013). JIC is collaborating with Ohio State University, RBG Kew and NIAB-EMR to conduct controlled trials of the susceptibility of a wide range of UK F. excelsior genotypes for responses to A. planipennis in quarantine conditions in the USA.
Sectors Agriculture, Food and Drink,Communities and Social Services/Policy,Environment,Leisure Activities, including Sports, Recreation and Tourism,Transport

URL https://www.forestry.gov.uk/fr/infd-9kchzr
 
Description Introduction of ash dieback and other pathogens of tree and shrub pathogens into the UK The evidence that H. fraxineus was pathogenic on ash in the UK at least as early as 2004 but probably even in the early 1990s (Wylder et al., 2018) pre-dates by several years the first formal record of the fungus in the UK (Sansford, 2013). It also pre-dates much of our scientific knowledge of the pathogen and the disease (Kowalski, 2006; Gross et al., 2012). The significance of lesions and other symptoms on planting stock and trees in the wider environment in the UK is therefore unlikely to have been appreciated, perhaps not even recognised. The high genetic diversity of H. fraxineus at both planted sites and in the wide environment imply that the fungus arrived in the UK by two routes in substantial amounts: on infected planting stock and as airborne spores from the continent (Wylder et al., 2018; Orton et al., 2017). Once sporulation of H. fraxineus began to take place at geographically diverse locations across the UK, the spread of the fungus was inevitable. Increasing global trade has resulted in the dispersal of numerous pests and pathogens across the world on imported plants, including many tree pathogens (Brasier, 2008; Roy et al., 2014). The UK has been a substantial importer of trees from continental Europe. Between 2003 and 2011, five million ash saplings were imported (Sansford, 2013) even though it was known, at least during the latter half of that period, that H. fraxineus was causing widespread damage to ash in exporting countries (Pautasso et al., 2013). Even so, ash dieback is only the most striking recent example of introductions which have led to destructive disease outbreaks in the UK when a parasite has encountered a highly susceptible host. Others which have recently been introduced by trade into the UK include Phytophthora ramorum, P. alni, P. lateralis, P. austrocedri, Cryphonectria parasitica and Dothistroma septosporum (Freer-Smith and Webber, 2015). The "Precautionary Principle" should be exercised in the trade in plants but this is not the case at present. On the contrary, the trading system within the European Union assumes that planting stock is safe to move unless proved otherwise (Brasier, 2008). To support disease management within such a system, it is important to understand the risks and consequences of pathogen transmission. In turn, this requires knowledge of how pathogen populations are structured and their potential for evolution within ecosystems in the UK. But this cannot be achieved while a disease and its pathogen remain poorly understood, which is the case for the great majority of the world's plant diseases. The results of the present project on ash dieback and other, related research imply that management of an introduced plant pathogen requires vigorous action to establish and enforce stronger measures to prevent movement of diseased plant material not just between continental Europe and the UK, but into and within Europe. The evidence that the ash dieback epidemic may have been initiated by as few as two individuals of H. fraxineus, possibly even as little material as one ascocarp (Gross et al., 2014; McMullan et al., 2018), indicates that coordinated efforts are required by national plant health authorities and the relevant industry, including forestry and nurseries. Reinvigoration of the nursery trade in the UK would help to reduce demand for imported trees. Educating the public to appreciate the beauty and interest of native trees instead of demanding ever more unusual exotic species, may help to reduce the flow of imported plants; perhaps this could be achieved a charismatic presenter of TV programmes on gardening championing the benefits of home-grown, native species. ???? ?????? ??? ???????, ?????? ????????? ????????, ???????????? ?????? ?????? ? ????, ?????? ? ?????? ????, ???????? ???????????? ?????? ???????. [The forests crack under the axe, billions of trees are dying, the dwellings of beasts and birds are ravaged, rivers are drying and drying, irrevocably miraculous landscapes are disappearing.] A. P. Chekhov, "Uncle Vanya" Potential for use of hypovirulence in control of ash dieback Hypovirulence, caused by the fungal mycelium becoming infected by a dsRNA virus, has been exploited for control of chestnut blight in North America and Europe (Rigling and Prospero, 2018). For this method to be effective, there must be a high probability that mycelia which encounter one another in the tree, soil or leaf litter are of the same VCG, so that viruses can spread through the fungal population. This is evidently not the case for H. fraxineus (Brasier and Webber, 2018; Orton et al., 2017), so it is very unlikely that hypovirulence can be used as a means of controlling ash dieback. Moreover, dsRNA viruses detected in H. fraxineus (Schoebel et al., 2014) were relatively benign, which would also limit the potential for using them in disease control. Plant management Other approaches to tree management and disease control are therefore required. Our research and observations in affected woodland support and extend previous conclusions that ascospores of H. fraxineus are produced in vast quantities and are occasionally dispersed over very long distances, and that the disease progress of ash dieback is slow but relentless. There is therefore almost certainly no value in attempting to restrict the spread of the pathogen or the disease, now that it is firmly established in the UK and has become severe in several counties. Essentially, we will have to live with ash dieback. This project does not indicate specific methods of managing diseased woodland or individual trees. It has been proposed that individual trees can be protected against dieback for some years by selective pruning of diseased branches (note correspondence in the October 2017 issue of Quarterly Journal of Forestry). Presumably this works by physically removing the slow-growing fungus before the infection progresses into the trunk or a large bough, but the intensive labour required means it is only economically feasible for individually valuable trees or small woods with good access in areas where disease pressure is low. Until resistance of F. excelsior to ash dieback becomes more widespread in the UK, it will be necessary to manage diseased trees to prevent injury to people and livestock as well as damage to vehicles, buildings and transport routes. As disease progress within an infected mature tree is usually slow, however, early preventative measures such as pre-emptive felling are not generally required or indeed recommended. On the contrary, landowners are encouraged to leave trees in an affected area unless they become hazardous, to ensure that potentially resistant trees are not removed unnecessarily. It will also be necessary to plant alternative tree species where required for ecosystem services, particularly to consolidate river and canal banks to prevent erosion and flooding, a function for which ash has been especially important. This has been discussed extensively elsewhere (Mitchell et al., 2014; Forestry Commission, 2017). Resistance and recovery In the course of our research on populations of H. fraxineus, it has become apparent that as elsewhere in northern Europe (McKinney et al., 2014), there is substantial variation in the degree to which ash trees are damaged by dieback. As there is a substantial fitness cost of pathogenicity in the fungus (see above: Objective 3) and as ash and H. fraxineus are sexual organisms, we predict that in time, ash and the ash dieback pathogen will co-evolve to a balanced equilibrium in which there is a moderate level of resistance in the tree population and moderate pathogenicity in the fungus, as in rabbits and the myxoma virus (Kerr et al., 2015). We cannot yet predict what the strength or frequency of host resistance or pathogen aggressiveness will be in the long term, nor how long it will take for this balanced equilibrium to be achieved. The lesson for tree management in future is to take rigorous action to prevent another equally damaging pathogen from entering the UK. Movement of ash plants and wood Regarding genetic diversity of H. fraxineus in its native range (see below: 'Prospects for future research'), the practical point is that if new genotypes of H. fraxineus arrive in Europe, they may (or may not - we cannot tell in advance) be more damaging than the limited range of genotypes which are here at present. Newly arrived genotypes would interbreed with H. fraxineus already present in Europe, greatly increasing the genetic diversity of this harmful pathogen in the wider environment. In principle, even one ascocarp on one fallen leaf would very likely introduce new, unknown genetic variation (McMullan et al., 2018). A complete prohibition on movement into Europe of Fraxinus plants and ash wood, whether green or dry, would significantly reduce the risk of this happening. This requires cooperation between European countries both inside and outside the EU, including European regions of the Russian Federation. There seems to be no further practical advantage to restricting the movement of healthy ash plants or ash wood from healthy trees within the UK, because ash dieback has now reached every county and H. fraxineus is so well-adapted for long-distance dispersal. On the contrary, restoration of ash populations by planting with seed from trees which are predicted to have at least moderate dieback resistance or with grafts from such trees should positively be encouraged. The ban on imports of ash from continental Europe should remain in place, however, unless UK authorities are fully convinced that Europe-wide controls on import of ash from East Asia are rigorous and stringent. We are aware that such divergence between rules for trade within the UK and between the UK and other EU countries, based on a scientific understanding of ash dieback, is not in accordance with current EU legislation.
First Year Of Impact 2018
Sector Agriculture, Food and Drink,Communities and Social Services/Policy,Creative Economy,Environment,Leisure Activities, including Sports, Recreation and Tourism,Culture, Heritage, Museums and Collections,Transport
Impact Types Cultural,Societal,Economic,Policy & public services

 
Description Advice to House of Lords on plant biosecurity, especially trees: discussion with policy advisor to HoL Energy & Environment Select Committee regarding future biosecurity for UK woodlands and farming
Geographic Reach National 
Policy Influence Type Gave evidence to a government review
 
Description Advised DEFRA following a request for information following the potential threat from H. frxineus strains not yet present in Europe
Geographic Reach National 
Policy Influence Type Gave evidence to a government review
 
Description Discussions with Norfolk County Council on management of ash dieback and restoration of ash in Norfolk
Geographic Reach Local/Municipal/Regional 
Policy Influence Type Participation in a advisory committee
 
Description Engagement with Government: Advice to JNCC regarding deployment of resistant Ash trees
Geographic Reach National 
Policy Influence Type Gave evidence to a government review
Impact Dr Elizabeth Orton and Prof James Brown gave evidence based advice about how to proceed with developing a plan to deploy resistant ash.
 
Description Forest Pathology Group Presentation on ash dieback
Geographic Reach National 
Policy Influence Type Influenced training of practitioners or researchers
 
Description Hosted visit by Future Trees Trust and gave advice on current situation regarding testing for resistant ash trees in UK.
Geographic Reach National 
Policy Influence Type Influenced training of practitioners or researchers
 
Description Input to DEFRA review of research on ash
Geographic Reach National 
Policy Influence Type Participation in a national consultation
 
Description Meeting of Dr Joan Webber (Forest Research) with Rt Hon Michael Gove, Secretary of State for the Environment, Food and Rural Affairs.
Geographic Reach National 
Policy Influence Type Participation in a national consultation
 
Description Participated in DEFRA organised Ash Dieback Research Oversight Group (ADROG) meeting
Geographic Reach National 
Policy Influence Type Participation in a national consultation
 
Description Presentation and Discussion with Deputy Director for Animal and Plant Health Evidence and Analysis, DEFRA at JIC.
Geographic Reach National 
Policy Influence Type Participation in a national consultation
 
Description Presentation to Nicola Spence, DEFRA Chief Plant Health Officer on visit to JIC
Geographic Reach National 
Policy Influence Type Gave evidence to a government review
 
Description Seminar hosted by HRH Prince Charles on tree health & biosecurity, attended by Dr Joan Webber (Forest Research)
Geographic Reach National 
Policy Influence Type Membership of a guideline committee
Impact National consultation on tree health and biosecurity, including researchers, academics, NGOs, industry, etc hosted by HRH Prince Charles at Highgrove.
 
Description Student at Forest Research working on ash dieback, in collaboration with Woodland Trust and Network Rail
Amount £90,000 (GBP)
Organisation Department For Environment, Food And Rural Affairs (DEFRA) 
Sector Public
Country United Kingdom
Start 11/2017 
End 12/2020
 
Title JENNIFER collection of ash 
Description With East Malling Research, JIC established the JENNIFER collection of ash genotypes as a national resource for research in the UK. JENNIFER = John Innes / East Malling National Nursery for Integrated Fraxinus excelsior Research 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? Yes  
Impact Field trial of the JENNIFER collection planted at a site near Acle, Norfolk 
 
Description Collaboration of FR with BOKU, Austria 
Organisation University of Natural Resources and Applied Life Sciences
Country Austria 
Sector Academic/University 
PI Contribution Collaboration of Joan Webber & Clive Brasier, Forest Research, with Thomas Kiritsis, BOKU, Austria, on ecological genetics of Hymenoscyphus albidus.
Collaborator Contribution Information on breeding strategies of Hymenoscyphus albidus in Europe.
Impact Paper on ecological genetics and breeding systems of Hymenoscyphus albidus in Forest Ecology.
Start Year 2015
 
Description Collaboration on emerald ash borer 
Organisation East Malling Research
Country United Kingdom 
Sector Academic/University 
PI Contribution Identification of suitable Fraxinus excelsior accessions from the JENNIFER collection for emerald ash borer trials. Data analysis. Leading the publication.
Collaborator Contribution RBG Kew: Formation of collaboration and planning experiments. EMR: Provision of plant material for EAB experiments. OSU: Conduct of experiments and data analysis.
Impact A paper has been accepted subject to revision, reporting data on response of UK Fraxinus excelsior to emerald ash borer in controlled trials.
Start Year 2016
 
Description Collaboration on emerald ash borer 
Organisation Ohio State University
Country United States 
Sector Academic/University 
PI Contribution Identification of suitable Fraxinus excelsior accessions from the JENNIFER collection for emerald ash borer trials. Data analysis. Leading the publication.
Collaborator Contribution RBG Kew: Formation of collaboration and planning experiments. EMR: Provision of plant material for EAB experiments. OSU: Conduct of experiments and data analysis.
Impact A paper has been accepted subject to revision, reporting data on response of UK Fraxinus excelsior to emerald ash borer in controlled trials.
Start Year 2016
 
Description Collaboration on emerald ash borer 
Organisation Royal Botanic Gardens, Kew
Country United Kingdom 
Sector Charity/Non Profit 
PI Contribution Identification of suitable Fraxinus excelsior accessions from the JENNIFER collection for emerald ash borer trials. Data analysis. Leading the publication.
Collaborator Contribution RBG Kew: Formation of collaboration and planning experiments. EMR: Provision of plant material for EAB experiments. OSU: Conduct of experiments and data analysis.
Impact A paper has been accepted subject to revision, reporting data on response of UK Fraxinus excelsior to emerald ash borer in controlled trials.
Start Year 2016
 
Description Collaboration with NIBIO, Norway, to try to determine population structure of H. albidus in UK 
Organisation Norwegian Institute of Bioeconomy Research
PI Contribution Provided samples and post-doc to access sequencing technologies.
Collaborator Contribution Provided expertise and equipment to sequence samples
Impact Data are inconclusive
Start Year 2015
 
Description Establishment of JENNIFER population of ash genotypes 
Organisation East Malling Research
Country United Kingdom 
Sector Academic/University 
PI Contribution Production of replicated clones of 328 Fraxinus accessions in the JENNIFER collection, for future research on ash including ash dieback, resistance to herbivores and phenological traits.
Collaborator Contribution East Malling: Cloning the Fraxinus accessions by grafting. Norfolk CC and Forest Research: Provision of trial sites with deer fence for ash dieback trials.
Impact Planted field trial near Acle, Norfolk, January 2018.
Start Year 2015
 
Description Establishment of JENNIFER population of ash genotypes 
Organisation Forest Research
Country United Kingdom 
Sector Public 
PI Contribution Production of replicated clones of 328 Fraxinus accessions in the JENNIFER collection, for future research on ash including ash dieback, resistance to herbivores and phenological traits.
Collaborator Contribution East Malling: Cloning the Fraxinus accessions by grafting. Norfolk CC and Forest Research: Provision of trial sites with deer fence for ash dieback trials.
Impact Planted field trial near Acle, Norfolk, January 2018.
Start Year 2015
 
Description Establishment of JENNIFER population of ash genotypes 
Organisation Norfolk County Council
Country United Kingdom 
Sector Public 
PI Contribution Production of replicated clones of 328 Fraxinus accessions in the JENNIFER collection, for future research on ash including ash dieback, resistance to herbivores and phenological traits.
Collaborator Contribution East Malling: Cloning the Fraxinus accessions by grafting. Norfolk CC and Forest Research: Provision of trial sites with deer fence for ash dieback trials.
Impact Planted field trial near Acle, Norfolk, January 2018.
Start Year 2015
 
Description JIC/FR collaboration on Chalara ash dieback 
Organisation Forest Research
Country United Kingdom 
Sector Public 
PI Contribution Research on pathology, molecular markers, population genetics and natural selection in Chalara ash dieback.
Collaborator Contribution Research on pathology, population genetics and forest management in relation to Chalara ash dieback.
Impact Papers in peer-reviewed journals: published and in press. Advice to Forestry Commission and DEFRA. Public awareness activities. Advice to forestry industry. Disciplines: plant pathology (particularly forest pathology), population genetics, forestry.
Start Year 2014
 
Description Review of ash resources in UK and impact of dieback 
Organisation Earth Trust
Country United Kingdom 
Sector Charity/Non Profit 
PI Contribution Review of ash genetics resources and impact of dieback in the UK.
Collaborator Contribution Review of ash genetics resources and impact of dieback in the UK.
Impact Book chapter by Clark & Webber.
Start Year 2015
 
Description Advice by Dr Joan Webber (Forest Research) to Forestry Commission on tree management related to ash dieback 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact Advice by Dr Joan Webber (Forest Research) to Forestry Commission on management of trees related to falling boughs and whole trees caused by ash dieback.
Year(s) Of Engagement Activity 2018
 
Description Advisor, Nornex 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Prof James Brown was one of the two advisors to the Nornex project on ash dieback, contributing knowledge about population genetics and plant breeding.
Year(s) Of Engagement Activity 2013,2014,2015,2016
 
Description Appearance by Dr Joan Webber (Forest Research) on Countryfile Winter Diaries, BBC1 
Form Of Engagement Activity A broadcast e.g. TV/radio/film/podcast (other than news/press)
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Media (as a channel to the public)
Results and Impact Interviewed for BBC1 TV Countryfile Winter Diaries about tree diseases, including ash dieback.
Year(s) Of Engagement Activity 2018
 
Description Article on ash dieback in the John Innes Centre 'Advances' magazine. 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Article on ash dieback written for the print and online publication Advances by the JIC to report on the work happening on the project.
Year(s) Of Engagement Activity 2017
 
Description Article on on the Ash dieback project featured in NERC's magazizne Planet Earth 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact An article was written for NERC's magazine to show what was currently being funded and the work we intended to do.
Year(s) Of Engagement Activity 2014
 
Description Attended and presented a poster at the international conference 'Genetics of Tree-Parasite Interactions' in Orleans, France 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact We presented our ongoing work to a international community of delegates as well as meeting local landowners to discuss impacts of tree diseases.
Year(s) Of Engagement Activity 2015
 
Description Discussions with DEFRA about ash research requirements 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Policymakers/politicians
Results and Impact Discussion with DEFRA officials about the impact of current research on ash dieback, notably research at JIC, for policy on control of ash dieback and for international trade in live plants, timber and firewood. These conclusions of the discussion fed into a strategy meeting held in January 2019 and will thus feed into a strategy document being written by DEFRA.
Year(s) Of Engagement Activity 2018
 
Description Dr Joan Webber (Forest Research) regularly updated FR ash dieback project pages. 
Form Of Engagement Activity Engagement focused website, blog or social media channel
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Regular updates of Forest Research web pages on ash dieback with information relevant to the general public, industry, policy-makers and others.
Year(s) Of Engagement Activity 2014,2015,2016,2017,2018
 
Description Dr Joan Webber, Forest Research: professional advice to student at National School of Forestry & University of Cumbria 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Postgraduate students
Results and Impact Advice to an undergraduate student at the University of Cumbria and National School of Forestry relating to his thesis on, 'The effect of Chalara dieback and rainfall on tree-ring increment in European ash (Fraxinus excelsior)'.
Year(s) Of Engagement Activity 2015,2016,2017
 
Description Dr Joan Webber, Forest Research: visit by Chinese forest pathologists 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Study visit by Chinese scientists to Forest Research, including Dr Joan Webber, to learn about current research on ash dieback.
Year(s) Of Engagement Activity 2015
 
Description Hosted a visit of representatives from The Woodland Trust,Tree Council, Norfolk and Suffolk County Councils 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Stakeholders with an interest in woodlands and the environment visited the institute to discuss the impact of ash dieback on land management practice and understand implications for the disease in the short and longer term. They left with a better understanding of the disease and raised many questions about future research areas,
Year(s) Of Engagement Activity 2017
 
Description Meeting with Natural England, about ash dieback 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Policymakers/politicians
Results and Impact Prof James Brown updated science advisor to Natural England on current situation of ash dieback, prospects for recovery and future threats to woodland
Year(s) Of Engagement Activity 2017
 
Description On camera interview with BBC local news and press release published by local newspaper. 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Interview and press release on our recently published paper on ash dieback attracted interest form local news outlets and led to questions from public.
Year(s) Of Engagement Activity 2017
 
Description Presentation to British Society for Plant Pathology Annual Meeting about the project and findings regarding population structure 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact Presented the current findings of out work on populations structure of the pathogen in the UK to researchers including postgraduate students. This sparked discussion afterwards.
Year(s) Of Engagement Activity 2016