Plant pathogens have been a challenge for food security since the beginning of the domestication of wild plants. Several plant diseases have contributed to significant societal changes. One of the most devastating outbreaks of plant pathogens happened in the 19th century in Ireland, when Phytophthora infestans spread rapidly throughout the country and ravaged the main source of food – the potato. Irish Potato Famine or the Great Hunger resulted in the death of roughly one million people from starvation and related causes and at least another million were forced to leave their homeland. Today, the danger of such extensive damages is alleviated by better plant health, which includes all aspects from healthy seeds, regular monitoring, and survey programs to agricultural technology. The awareness of potentially devastating socioeconomic consequences of harmful organisms is higher than ever before, and many efforts at national and international levels have led to a better understanding of plant pest epidemiology and management. Nevertheless, in the European Union (EU) we are currently dealing with the devastating consequences of bacterial blight of olive threes caused by a quarantine bacterial pathogen Xylella fastidiosa.
For efficient management of harmful organisms, harmonisation and standardisation is needed among laboratories, to provide decision makers with technically sound and comparable results. Besides setting up quality management systems, common approaches for the introduction and validation of new methods are needed. This has been recognised also by the European Plant Protection Organisation (EPPO) that has established a work program in the area of diagnostics to harmonize procedures across the EPPO region. Several EPPO standards are available (https://www.eppo.int/RESOURCES/eppo_standards/pm7_diagnostics), which describe different classical and molecular methods for each organism that can be used by laboratories, as well as how validation should be conducted. Moreover, in line with their capacities, laboratories can use different methods, which can greatly vary in sensitivity. Consequently, the comparability of results among different laboratories is compromised and can lead to socioeconomic consequences and international trade disputes.
The main objective of the proposed research is to design and evaluate a metrological framework, which would underpin plant pathogen diagnostics, so that correct steps in the prevention of the spread of the plant pathogens can be assured, and with that potential economic fallout or even famine can be prevented. The specific objectives of this research project are:
- to define the core measurement requirements for accurate and reproducible measurements associated with investigation and management of plant pathogenic bacteria,
- to develop quantitative, validated, and highly accurate measurement procedure(s),
- to investigate possibilities to use materials of different level of complexity (e.g. synthetic DNA, plasmids, genomic DNA, whole organisms) as potential reference materials with the special emphasis on their commutability,
- to use the developed measurement procedure(s) and materials to investigate existing approaches and methods used in the plant pathogen testing laboratories, and finally
- to suggest a metrologically underpinned approach in a form of guidelines for the development of reference materials and reference method(s) for plant pathogen diagnostic and research.
The proposed research will bring a fuller understanding of the need for metrological support in plant health and contribute to the prevention of the spread of disease, such as infection of olive trees with Xylella fastidiosa bacterium. The development of reference material(s) and method(s) will also have a great impact on the proficiency testing schemes and will consequently notably contribute to comparability and standardisation of plant pathogen diagnostics. The principle of development of reference methods and materials will be transferable to uncultivable bacteria and other plant pathogens, such as viruses and phytoplasmas.