New approaches for the early detection of tree health pests and pathogens

Lead Research Organisation: University of Exeter
Department Name: Biosciences


The UK's forests, woods and trees are under threat from a growing number of pests and diseases. Many of these threats are alien; historically not present in the UK and having been introduced from overseas. Some of these threats may reach the UK naturally i.e. as wind-borne spores from continental Europe; potentially one pathway for introduction of the disease ash die-back. The alternative and probably more common pathway of introduction is via human activity, especially trade; for example moving infected plants (another pathway identified for ash die-back) or through the shipping of goods associated with infested timber (as was the case with the recent introduction of the Asian long-horn beetle into Kent in packaging crates for stone). These cases clearly demonstrate that we need to do more to improve our nation's biosecurity and protect our plants and trees; both cultivated and in the wider environment.
In order to do this we need better methods for detecting these pests and diseases that allow us to find them earlier and with greater efficiency. By detecting these threats earlier you can minimize the damage they cause, by either preventing an outbreak occurring in the first place or by finding it early and then stopping it from establishing and spreading further. At present we rely on trained inspectors to find these alien pests and pathogens, mainly via visual inspections of imported plants and plant-based products e.g. timber. However, given the volume of inspections required, the finite amount of resource available and the huge practical challenges associated with these inspections, this task is extremely difficult and the efficiency of detection is low.
This project is designed to change that situation by providing better methods for detecting tree pests and pathogens; both moving in trade and in the environment. It will look at new technologies for the detecting changes in infected plants; using either 'sniffer' technology to identify differences in the volatile chemicals given off by diseased and healthy plants or imaging techniques that can detect changes beyond the range of human vision. It will also look at developing and designing novel traps for capturing insects and DNA-based detection approaches that look for air- and water-borne pathogens. This will include better approaches for trapping spores and then applying high-throughput sequencing methods that will allow the identification of not only known pathogens but also new ones too.
However, developing these new technologies is only part of the challenge. It is also necessary to make sure these new methods are fit-for-purpose and that they work in a way that meets the needs of those enforcing tree health regulations (e.g. government), those upon who those regulation impact (e.g. woodland owners and industry) and the end-users who would be expected to use these new tools (e.g. inspectors in the field). We will also examine what type of end-users could be involved; this could be trained government inspectors (the traditional approach) or alternatives such as those working in the industry, volunteers or even the general public. So looking to see if a so-called 'citizen science' approach could be used for any of these new approaches.
It is also important to ensure that these new approaches can be deployed effectively, for example at locations that pose the greatest risk, and in a way that offers the best cost-benefit (i.e. the best balance between cost of using the technology and the improvements it can offer in terms of better pest and disease detection). In order to do this, we will take an interdisciplinary approach; getting experts from many different fields e.g. biology, mathematics, chemistry, engineering, physics, economics and social science, to work together to come up with the best overall solution that works technically, economically and socially.

Technical Summary

This project has 6 work packages (WP), each based around a different combination of skills and expertise. For WP2-6 there will be a focus on a particular detection technology, while WP1 will provide the technical oversight needed for effective deployment of these different technologies, as summarised:
WP1:a participatory interdisciplinary approach will be used to evaluate the needs of stakeholders and to ensure that the technologies meet these. It will also focus on the requirements of effective technology deployment, using mathematical modeling to develop sampling strategies, to create network-based risk maps and economic assessments of cost-effectiveness. Further aspects of deployment will be analysed using social science approaches including end-user acceptability and the potential for using citizen science.
WP2:analytical chemistry approaches will be used to identify diagnostic volatile organic compounds produced by pests, pathogens and diseased hosts and to translate these onto commercial-available portable platforms for use by inspectors in the field.
WP3:multispectral imaging will be used to identify markers for the early detection of biotic/abiotic stress in plants. A prototype bioimaging camera will be constructed that can be used to validate this approach in the field.
WP4:will develop mathematical models of spore movement and investigate metagenomics for broad-spectrum surveillance utilizing existing monitoring networks e.g. pollen traps. In addition, a novel integrated cyclone-based trapping and molecular detection system will be developed and evaluated.
WP5:novel semiochemical attractants will be identified for a range of wood-boring beetle pests, incorporated into traps designed for efficient detection and then deployed in a risk-based network.
WP6:methods for sampling and rapid screening water for Phytopthora spp., including 'unknowns' will be developed and validated. This will combine high-throughput sequencing with a rapid bioinformatic.

Planned Impact

The interdisciplinary design of this proposal will ensure maximum ongoing impact. Central to this is stakeholder engagement and our proposal has adopted a novel approach to facilliate this. Traditional approaches to developing new detection or diagnostic technologies have assumed the 'build it and they will come' approach; where the focus is on the technical aspects of the novel methodology, rather than the needs of end-users and the specifics of how it will be effectively deployed. This proposal reverses that by taking an inclusive view of what is required to achieve a successful outcome i.e. the deployment of a new technology that improves our biosecurity, and then co-designs technologies which fit that purpose. It achieves this by embracing an interdisciplinary approach and through establishing early engagement with stakeholders and end-users. Critical to this is the creation of a Learning Platform (Work package 1) which sits at the core of the project and cuts across the other technology-driven work packages (WPs 2-6). This platform will create communication channels, facilitate collaboration and knowledge sharing across work packages and stakeholder groups, actively disseminating project outcomes and enabling the pathways to impact. This will be delivered as a series of workshops; both cross-cutting (looking at the broader issues associated with detection and its successful deployment) and more focused (looking at specific issues associated with a particular technology and the contexts for its use). In addition to interacting with stakeholders (e.g. policy-makers, inspectors, NGOs, industry), this approach will use the breadth of expertise established within the consortium and assembled from across a wide-range of disciplines. This brings together 'technology-owners' (natural and physical scientists) with 'technology-evaluators' (mathematical and social sciences) to ensure that the best technological approaches are married with suitable sampling and risk-based deployment strategies, that they have stakeholder acceptability and offer genuine cost-efficiency benefits to public and private stakeholders alike.

In addition to the novel approach built into the project design, the effective delivery of impact will also benefit from a consortium which has an extremely strong track record of delivering translation science, to policy and industry alike. As government science agencies, the major remit for both Fera and Forest Research is to take science and technology and to translate it into policy-focused tools and evidence. This is a role they provide routinely for Defra and Forestry Commission, and their associated inspectors on the frontline in the field (e.g. Fera PHSI and FC Inspectors). In terms of delivery of technologies to end-users including industry, there is also a strong track record across the consortium in a whole range of contexts e.g. Worcester (horticulture industry diagnostics), JHI (potato industry diagnostics), Greenwich (pest trap deployment) and Fera (field diagnostics deployment). The integration of a number of SMEs within the consortium is another pathway to impact; providing a route for new technologies to be made freely available beyond the end of the project. Finally as plant and tree health sits within a European regulatory framework, the ability to engage with international partners and stakeholders is important. The consortium has a wealth of experience and contacts in this area, in particular through its central role in a range of related EU-funded projects e.g. Q-Detect (Fera-led), ISEFOR (Aberdeen-led) and PERMIT (FR-led). It will also build upon existing systems for knowledge exchange within our region, especially through the use of the European Plant Protection Organization (EPPO). By working with EPPO, using activities such as its workshops and conferences, we will be able to reach out to tree health practitioners across Europe; in many cases the real frontline for UK biosecurity.
Description I am funded to contribute to Work package 6: Development of non-targeted water surveillance methods for water-borne tree pathogens based on metagenomic approaches ('Water surveillance')". Specifically, my contribution is to assist with development a bioinformatics pipeline for identification and reporting of the species detected in each sample and to provide bioinformatics guidance and expertise.

To this end, I have implemented a straightforward pipeline involving sequence similarity search using BLASTN and taxonomic identification using MEGAN. Having received Phytophthora ITS metabarcoding sequence data from the PI of this workpackage (i.e. Dr David Cooke at JHI), I have run my pipeline on this and reported the results to him.

Furthermore, I have attended various project meetings and other opportunities to sit down with fellow members of the "New approaches for the early detection of tree health pests and pathogens" consortium to provide advice on bioinformatics aspects of the project.

I have also used a proportion of my funded time towards generating sequence data from several tree-pathogenic Phytophthora species, which will aid future developments in sequence-based detection. this has led to several publications describing these datasets.
Exploitation Route All sequence data are publicly available via GenBank and SRA and may be accessed without restriction by any researchers. Details of bioinformatics pipeline will be described in full in any future publications arising from it.
Sectors Agriculture, Food and Drink

Title Phytophthora genomics data 
Description We have generated genome sequences for multiple isolates of several species of Phytophthora that cause disease on trees. 
Type Of Material Database/Collection of data 
Provided To Others? No  
Impact No notable impacts yet. However, the availability of these datasets will enable development of molecular detection/identification by others.