Xylella Fastidiosa Active Containment Through a multidisciplinary-Oriented Research Strategy

Work Packages

Workplan of the project

The XF-ACTORS Consortium has been set up to implement a multidisciplinary research program, organized in 10 work packages (WP).

WP1 – Coordination and Management of the Consortium.

WP2 – Biology and genetics of relevant X. fastidiosa strains.

This Work package aims at developing critical information on Xf pathogenicity, biology, and genomics, and to elucidate the potential epidemiological consequences of the establishment of novel Xf strains in the EU territory.

The information gathered in this WP will provide critical elements to determine the major EU crops threatened by Xf and particularly by those Xf strains that can be imported on contaminated plants in comparison to those that are already established in the EU.

New understanding of the evolution of the Xf population in the contaminated areas, and identification of critical parameters involved in Xf-plant interactions could indicate new ways on how to deal with and control disease risk under actual and future changing conditions of trade and climate.

Research outputs are to be implemented in WPs 6, 7, and 8. The involvement of the research centers located in Brazil, USA, Costa Rica and Taiwan, brings to this WP an important added value to better understand the genome-wide Xf diversity and the genetic evolution.

WP3 – Early detection of Xf symptoms using remote sensing.

This work package aims to determine the remote sensing methods that most efficiently detect the physiological and biochemical effects of early stages of Xf infection, across a range of scales and platforms.

While suspected Xf infections associated to olive quick decline (OQDS) have been successfully identified through visual interpretation of aerial photos (Gualano et al., 2014), the automated analysis of hyperspectral and thermal images will be needed to detect early, i.e. pre-visual, symptoms of Xf infection.

We aim to achieve this objective by starting with leaf level measurements in the laboratory, under controlled Xf infection levels, then testing methods at the leaf-scale in natural settings, and progressively scaling up measurements from the leaf, over the branch, to the crown, and the crop and landscape scale. To achieve the latter steps, ground and aerial vehicles will be used.

WP4 – Implementation of sampling schemes and innovative tools for early detection of X. fastidiosa in host plants.

The overall goal of this WP is to develop diagnostic tools that, coupled with the outcomes of the activities focusing on “Early detection of Xf symptoms using remote sensing – WP3”, will provide tools and procedures for an early surveillance system, paramount to support pest management activities.

To control Xf spread it is crucial that newly infected sites are quickly detected so that measures can be implemented to face the epidemic (Parnell et al., 2014; 2015). However, since not all locations can be inspected there is a need to define criteria for prioritization of the sites for surveying and to define sampling size.

The research program will specifically develop innovative monitoring procedures and user friendly tools/devices for rapid detection of Xf in host plants and insects. Indeed, implementation of a pre-existing field smart application (XylAppPuglia, which is made available to the consortium), for an accurate localization of monitoring sites/plants and the acquisition of field data, will be accomplished.

WP5 – Vector biology and ecology and role in disease epidemiology.

The objective of this work package is to provide critical information about the occurrence and bioecology of confirmed and potential vectors of Xylella fastidiosa (Xf) and about the specifics of the transmission of Xf by European vectoring species. Knowledge of these data is a prerequisite for the development of effective integrated management strategies but also for the rational risk assessment with regard to the inadvertent introduction of Xf in new areas.

The aim of this WP are studies (i) on the occurrence and potential vectoring ability of xylem-sap feeding Auchenorrhyncha; (ii) on the biology and ecology of species identified as vectors of Xf or being considered candidate vectors for yet non-affected areas; (iii) on the interactions of Xf and vectors and implications for the transmission process. Furthermore, (iv) the population genetics of key potential vectors and the association of Xf and other microorganisms with xylem-sap feeding species will be analysed.

These studies are extending the work carried out in POnTE to other geographic regions and agroecosystems, by including further bioecological studies and by adding more detailed studies on the pathogen-vector interactions and the transmission process. Results obtained by this WP should help WP6 to set up innovative tools for the control of insect vectors and disease.

WP6 – Innovative and sustainable approaches for bacterial control in the host plants.

The objectives of this work package cover different approaches and aspects, towards the development of innovative tools for bacterial control (signaling compounds, antimicrobial peptides, bacteriophages) integrated with environmental and economically sustainable strategies (plant microbiome biodiversity, search for tolerant/resistant host species/cultivars).

It is recognized that the key to durable (long-lasting) resistance to the pathogen in the field is to “stack” or combine different traits in order to control or modify various aspects of plant-pathogen interactions. Ultimately, multi-tiered approaches will probably be the most effective strategy in combating destructive plant pathogens like Xf, especially when there is a need to coexist with this pathogen upon its establishment in the field.

WP7 – Effective, innovative and sustainable approaches to prevent and minimize disease impact.

This research to be carried out within this WP aims at developing and validating management tools for reducing and minimizing the spread and the impact of X. fastidiosa (Xf) infections through an integrated frame of conventional and organic-based measures for sustainable control of the vector(s) and transmission disrupting resulting in the mitigation of Xf disease(s).

To this end direct information on the vector-pathogen-host interactions (deriving from the WP2-WP5) will be used for developing innovative tools, mainly focusing on xylem-feeders population management in Xf free areas (prevention measure) plus minimizing the Xf reservoirs in infected areas (containment measure).

These objectives will be accomplished by (i) developing new acoustic traps; (ii) identifying plant-derived compounds that could alter the behavior of P. spumarius; (iii) identifying endosymbiotic bacteria as potential biological control tool of X. fastidiosa vector; (iv) field trials aimed at validating the impact of roguing infected trees in the epidemic area; (v) designing an IPM and an Organic control programs to reduce vector populations. Such programs will start from the results gathered in POnTE.

WP8 – Regional risk assessment to anticipate the threat and impacts of Xf diseases.

This work package aims to establish more effective mechanisms and tools for risk assessment and prevention, as well as preferred strategies for eradication. Regionalized analyses will be based on selected case studies in different countries with past and current outbreaks, as well as vulnerable disease-free areas.

Relevant parameters (e.g. epidemiology of Xf diseases, hosts, spread, social structure, governance, and environmental impacts) will be considered to develop risk assessment models at regional scale. The likelihood of disease presence and further epidemic spread to new regions will be evaluated by empirical and process-based models.

Using these models, risk management options will be considered quantitatively, addressing the current outbreak of Xf subsp. pauca in Italy as well as potentially threatened areas. In addition, generic modelling approaches will be used to devise risk management strategies for the different Xf diseases threatening the EU.

Cost/benefit analysis based on the same case studies, will be developed for disease surveillance, eradication plans and other risk management strategies at regional level to prevent and contain Xf spread. This will be achieved by assessing their efficiency in disease management but also their potential negative impact and social, economic and environmental consequences in the short term (e.g. removing trees, losing production, social costs, etc.) and in the long term (e.g. unemployment, soil degradation, loss of biodiversity, etc).

WP8 will use knowledge from POnTE as well as that provided by WPs2-5 for risk analysis and disease modelling, and WPs5-7 for the cost/benefit analysis. The results of WP8 will serve as inputs to fulfilling the goals of WP9 and WP10.

WP9 –  Building capacity and competence to strenghten and implement the EU plant health regime.

The WP aims at compiling the knowledge on the Xylella fastidiosa bacterium and the associated disease, and increasing skills and expertise for strengthen EU biosecurity plans. It will also generate comprehensible information for WP10 that deals with communication and distribution to the general public and in particular to persons, organisations or companies that are prone to human assisted introduction and spread (trade + traffic = trouble).

In particular, the tasks will elaborate good-practice guidelines based on available and project-generated scientific and technical evidence on Xf and with the following more specific Objectives:

  • To install a dynamic Xf web-portal in open access format, widely consultable and informative for the different types of stakeholders and in condensed form also for the public, and with a sustainable management also after the project period.
  • To assist plant health administrators by providing standards for organizing surveys and sampling (by incorporating knowledge resulting from the project to update the existing EPPO Standards on inspection), for pathogen confinement and eradication, and by studying the possibility for a network of quarantine stations at EU entry points.
  • To substantiate the competence and capacity of plant health laboratories for official Xf testing by installing a laboratory network and providing training in Xf diagnosis and detection.
  • To elaborate and describe conditions for production of Xf-free plant propagation material in support of plant certification.

WP 10 –  Communication and dissemination.

This work package aims at developing dissemination and communication strategies and tools.

The main goals are: structuring dialogue with stakeholders to establish the project participatory approach; contributing to increase scientific knowledge education transfer about Xf; raise awareness; optimizing the quality of dissemination; structuring communication with unambiguous content and timely information; establishing communication networks to cope with risk prevention practices and management; allowing monitoring; supporting the information sharing among operators parties involved in the prevention, monitoring and control of the phenomenon.

To cope with all these goals, a communication and dissemination strategy will be developed and the activities will see the participation of project partners and the involvement of external actors like stakeholders, researchers, civil society and media. Several events are foreseen in accordance with the related tasks.