Prevention of the quarantine bacterium Xylella fastidiosa introduction through plant propagation material

Project leaders

Pasquale Saldarelli, Tatjana Perovi

Agreement

MONTENEGRO - MoS-not in force - Ministero della Scienza del Montenegro

Call

CNR-MoS 2017-2018

Department

Biology, agriculture and food sciences

Thematic area

Biology, agriculture and food sciences

Status of the project

New

Research proposal

Xylella fastidiosa (Wells et al.) (Xf) is a xylem-inhabiting bacterium with a wide range of different plant hosts (up to now 359 natural or artificial host species, belonging to 204 genera and 75 botanical families, reported and listed in the EFSA database ), mainly woody perennial plants (trees, shrubs and subshrubs), crops, forestal, wild and ornamental plants. Plant-to-plant transmission of the bacterium is only mediated by insect vectors of Cicadellidae (sharpshooters) and Aphrophoridae (spittlebugs) families. Xf is worldwide known to affect and cause important crop loss and damages on grapevine in the USA, Coffea spp. and Citrus spp. in Central and South America, stone fruits, forestry and ornamental species, etc. Vector transmission and its wide host range make Xf a major threat for agricultural productions and for the plant material global trade, being included at the top of the lists of quarantine organisms harmful for plants in EU and all other Mediterranean Countries. Due to the lack of curative products/strategies, Xf is able to destroy entire productions/sectors and eventually kill the plants it colonizes. The 2013 first detection of Xf subspecies pauca in Europe, as evidenced by its widespread distribution in the southern region of Apulia in Italy (Martelli et al., 2015), as well as its finding in France throughout Corsica and in PACA region, where strains of the Xf subspecies multiplex have been found, have greatly increased the awareness of the threat that this pathogen potentially poses to Mediterranean agriculture and environment. Following the outbreaks in Italy and France, EU introduced compulsory measures (COMMISSION IMPLEMENTING DECISION (EU) 2015/789) imposing strong limitations to the exchange and trade of plant materials among Countries, which aimed at preventing the introduction, establishment and spread of Xf within the EU territory. These measures are particularly restrictive for non-EU Countries as Montenegro, which are obliged to verify and formally communicate to the EC (http://ec.europa.eu/food/plant/plant_health_biosecurity/legislation/emergency_measures/index_en.htm) their official status of Xf-free Countries, before to introduce in EU any plant material (including also samples to be analysed) belonging to any of the 359 species so far reported as Xf hosts.
The history of Xf introduction in EU on olive is a classical example of colonization of a new area. Xf was probably introduced in Salento (Apulia, Italy) as a single event, with infected plants imported from Central America and found olive as a new important host in presence of an efficient vector (the meadow spittlebug Philaenus spumarius), which is widespread in the Mediterranean basin. These concurrent events and the consequent outbreaks perfectly show the danger of this bacterium for EU and make the adoption of further surveillance efforts and preventive measure an urgent and crucial need. These measures are valid for the Xf-free Countries and Regions as well for the infected areas (such as Salento in Apulia Region), where the introduction of new subspecies or strains could give rise to recombination events and further disasters.
Besides the need of the deputy Institutions (i.e. EU, Ministries and Phytosanitary services) to strengthening or reform the phytosanitary quarantine and control systems at the borders (especially at the entry points of plant material from third Countries), an efficient prevention system is based on further key elements such as: 1) a thorough knowledge of the pathogen and its host range; 2) observations of the life cycles and behaviours of vectors; 3) surveys for the presence of Xf in target areas by a continuous monitoring of susceptible plant species or the identification of local host range; 4) the availability of expertise, facilities and laboratories necessary to detect and identify Xf; 5) an informative campaign to create public awareness about the risk of accidentally importing alien quarantine organisms and the correct behaviours to prevent their introduction.
The present proposal aims at contributing to the development of a national system made of knowledge, protocols, expertise and facilities, to prevent new potential introductions of Xf both in Country and Regions, nowadays known to be Xf-free (such as Montenegro) and in areas already infected by one or few strains of this bacterium.

Research goals

A safe and controlled exchange of plant material, even for research and experimental purposes, is required to protect the agriculture industry and the natural environment of Italy and Montenegro. The proposal will contribute to strengthening the ability of both Countries in preventing the introduction of different subspecies and strains of Xf through plant material imported from abroad. In order to achieve this goal the proposal has the following specific objectives: 1) To confirm the absence of Xf in Montenegro (by establishing a survey program), a step required to declare the status of Xf-free Country; 2) To deeper investigate the host range of Xf subsp. pauca CoDiRO strain in Apulia Region; 3) To strengthening the ability of both Countries (training of skilled personnel and development of laboratory facilities) for the adoption of preventive, early detection and/or eradication/containment measures to avoid the introduction and spread of Xf (different subspecies and strains) in the two Countries; 4) To increase the public awareness and attention about the risk of introduction of Xf and other quarantine harmful organisms; 5) To strengthen the effort of coordination and integration amongst the research groups based in the trans-Adriatic Countries.

Last update: 24/04/2024