Strategic preemptive pathogen surveillance of air and water to anticipate plant disease emergence in scenarios of changing land use – SPREE

Anticipating emerging infectious diseases and mitigating their impacts are the major challenges of Human, Veterinary and Plant Pathology. Surveillance for the detection of plant diseases and the subsequent response to limit their effects mobilize significant human and economic resources in Europe and elsewhere. Current plant disease surveillance plans of national and international organizations target known pathogens in the context of agriculture or commercial exchange or are based on symptom expression in the field. These surveillance plans do not monitor dissemination of plant pathogens by the natural “highways” of air and surface water movement and they do not involve tracking potential but-not-yet-described pathogens before they have caused a disease outbreak. Air and surface waters can move plant pathogens across distances of meters to hundreds and even thousands of kilometers and there are numerous examples of plant disease outbreaks due to these means of dissemination. Furthermore, the natural movements of air and water have the particularity of not only disseminating known pathogens of crops but also of bringing microorganisms from a diversity of habitats into contact with agricultural production fields. These habitats include ecosystems without agriculture, where the pathogenic potential of indigenous microorganisms is unknown and has generally been disregarded by plant pathology. Therefore, a plan for surveillance of aerial and water-borne dissemination of pathogens would be complementary to existing disease surveillance measures that involve importation restrictions of plant tissues and monitoring of disease symptoms in the field. It would markedly enhance the effectiveness of current surveillance by providing a means to monitor for unknown, potentially new pathogens traveling on natural highways in addition to known pathogens disseminated within the context of agriculture and commerce.

In this project we will bring together competence in biology, math and economics to leverage recent developments concerning the ecology of plant pathogens in natural environments, network analyses, epidemiological modeling, and land use mapping and simulation to develop a framework for surveillance of dissemination of plant pathogens via air and surface water movements. The project will involve partners who have worked together for several years to develop the tools and resources to build this framework. We will focus on plant pathogens for which we have confirmed their presence in habitats outside of agriculture and in particular in waterways and the atmosphere: Pseudomonas syringae, Pectobacterium spp. and Dickeya spp. We will focus our analysis on the Durance river basin in Southern France. We have worked at multiple field sites in this basin for over a decade and know its hydrology and meteorology well. We have also established large culture collections of the model bacteria from this basin in preparation for this study. Importantly, this basin is also in the PACA (Provence Alpes Côtes d’Azur) region, one of the only regions in Europe where fine-scale land use data are available. These data include over 900 digital cadastral maps, the associated fiscal data on land and private property, information on land use regulation and on the nature of farmland including crop type at the field level. The partners of this project are involved in the management of a geomatic platform for the analyses of these and other spatial data. This context puts us into the unique position of being able to develop a framework for surveillance of aerial and surface water dissemination of plant pathogens with the most modern tools and concepts and the full interdisciplinarity needed for this development. It also facilitates our ability to set up relationships with stewards of plant disease surveillance and policy makers to foster understanding of our work, transfer of technology and development of policy recommendations.