Suchergebnisse

'Pest Organisms Threatening Europe' (POnTE) is a four-year H2020 Project (grant agreement number 635646), started in November 2015, targeting emerging pests that threaten EU agriculture and forestry to develop knowledge and tools to minimise their impact and the risk of introduction in pest-free areas. The bacteria Xylella fastidiosa and Candidatus Liberibacter solanacearum and their vectors, as well as the phytopathogenic fungi causing major diseases in forestry and landscape trees, i.e Phytopthora spp. and Hymenoscyphus spp., were studied by a multidisciplinary team representing more than 20 Partners. The most relevant part of the project workplan was dedicated to studying the biological, genetic and epidemiological aspects of the bacterium X. fastidiosa spreading in olives in southern Italy. The bacterium, its vectors and the host response has been explored using innovative approaches and the knowledge gathered has significantly improved the current methods for diseases surveillance and prevention. Whereas, the preliminary results of the studies on the spittlebugs, olive microbiome and mechanisms of resistance in olive cultivars opened up new opportunities for the implementation of future applied research programmes on sustainable control strategies. The research programme has been supported by intense communication and dissemination actions, promoting research networking, harmonisation of the surveillance strategies and transfer of knowledge to stakeholders. Several scientific evidences collected in the framework of the project have been used to support and update the pest risk assessment and to implement the legislative measures enforced at EU and national level. The most significant achievements of the project will be briefly illustrated.

The International Research Consortium POnTE (Pest Organisms Threatening Europe) is being funded by the European Commission under the Horizon 2020 programme to investigate four pathogens (i.e. Xylella fastidiosa, Candidatus Liberibacter solanacearum, Hymenoscyphus fraxineus and Phythophthora spp.) representing a major threat to strategic crops and natural landscapes in the EU, and identify integrated management strategies for their containment. The wide range of studies conducted within the Project tasks on key emergent pests and the rising request for accessing up-to-date references over the Internet, suggested the need to provide a larger variety of real-time information about the project and its targets for a much wider variety of end-users. A WordPress-based web portal (www.ponteproject.eu) has been created by the Coordination Team to support collaborative platform functions, enhance the project's visibility and provide in a flexible manner a rapid dissemination of valuable information, fostering raise of general knowledge and public awareness on relevant themes in plant pathology. Answering to the modern challenges, accounting for an effective webbased pest information system, the resource is intended as an open-access platform to share scientific achievements, upload promotional material and fact sheets, communicate conferences and training courses, report press review and legislative regulations. A social media presence on Twitter and Facebook channels was set up from the early stages in order to enable a two-way communication with a web-active audience and work towards a continuous engagement of the major plant pathology networking platforms and institutional accounts. To keep Project partners and interested parties always informed of the web site updates and encourage frequent visits, a newsletter is being released on a weekly basis.

Several fungal species have been found associated with the Olive Quick Decline Syndrome (OQDS) caused by X. fastidiosa CoDiRO strain, among which some have long been recognized as primary pathogens of many plants (i.e. Phaeoacremonium and Pleurostomophora spp.), whereas other have not been described before. The new species Ps. oleae and Ps. oleicola, were associated with brown wood streaking of various olive varieties, both on young and centenarian trees. In order to ascertain the role of these fungi in the OQDS, pathogenicity tests were performed both in glasshouse, on young plants, and in the open field, on centenarian olive plants cv Cellina di Nardò. In glasshouse tests, fungal strains (Ph. aleophilum B1a, Ph. rubrigenum N20, Ps. oleae Fv84, Ps. oleicola M24, Pseudophaeomoniella sp. M51), were inoculated alone or in combination with X. fastidiosa CoDiRO strain. For the test in the field, naturally X. fastidiosa CoDiRO-infected and uninfected centenarian plants were inoculated with the same fungal strains. Results from the glasshouse tests, collected two years after the inoculation, indicate that fungal strain(s) alone are able to colonize the olive xylem, and to cause wood streaking. However, only few twigs showed wilting symptoms. Conversely, the combined inoculations with X. fastidiosa CoDiRO, induced extensive OQDS wilting symptoms. To date, results from the field observation 8 months after fungal inoculation show no differences in symptoms severity between X. fastidiosa infected and healthy plants. Aknowledgment This work has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement N. 635646 "Pest Organisms Threatening Europe POnTE". Bibliography Nigro F., Boscia D., Antelmi I. 6 Ippolito A. 2013. Fungal species associated with severe decline of olive in southern Italy. Journal of Plant Pathology, 95, 668. Martelli G. P., Boscia D., Porcelli F. & Saponari M. 2015. The olive quick decline syndrome in southeast Italy: a threatening phytosanitary ...

The olive quick decline syndrome (OQDS) is a novel disease recently emerged in southern Italy and currently threating the Mediterranean olive-growing area. The disease was found to be associated with infections caused by the exotic bacterium X. fastidiosa, well known in the Americas as the causal agent of severe diseases of important crops, i.e. grapevine and citrus. In these species, looking for resistance is regarded as one of the most promising long term control strategies. In olives, cultivars displaying differential phenotypes have been observed in the field, with symptoms ranging from virtually no decline and limited desiccation in Leccino and FS-17® to severe decline and death cvs Cellina di Nardo and Ogliarola Salentina. However, the large variability of olive genetic resources, including both cultivated and wild olives remains to be explored. Several experiments are currently ongoing aiming at detecting new sources of resistance in plant materials representative of the genetic and geographical variability of the species, including commercial cultivars, genotypes from other Olea europaea subspecies, and selections from breeding programs. Identified resistant sources could serve as parental for breeding programs, as currently underway for other vascular diseases such as Verticillium wilt. The status and challenges of the currently ongoing activities will be presented. ; Acknowledgment This work has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement N. 727987 "Xylella fastidiosa Active Containment Through a multidisciplinary-Oriented Research Strategy XF-ACTORS".

The long latency period of X. fastidiosa for the majority of perennial hosts, such as citrus and olive, makes difficult the advance of plant-pathogen studies. Therefore the use of susceptible model plants is required. In this work we show the results of infection and symptoms of the tobacco varieties Havana and RP1, inoculated with three Sequence Types (ST) of X. fastidiosa subsp. pauca (ST13, ST16, and ST53). Eighty days after inoculation the percentage of infected plants was 100% in Havana and RP1 inoculated with ST13 (9a5c citrus-strain). With the ST16 (MF01- olive strain from Brazil), the percentage was 83% in Havana and 100 % in RP1. The lowest percentage of infection was observed with ST53 (CoDiRO strain) with 55 and 78% for Havana and RP1, respectively. Symptoms of small dark lesions surrounded by yellowing at margins were observed only for the ST13 colonizing either Havana or RP1. Significant reduction in plant size and development were observed for all strains infecting both varieties, but more significantly for RP1. In addition, leaf-yellow blotches between secondary veins were mainly observed on RP1 but with gradual intensity (more to less) when the plants were infected with the ST13, ST16 and ST53, respectively. These results demonstrated that tobacco is a good model plant for X. fastidiosa subsp. pauca, although different varieties could show different level of infection and symptoms. In this work we verified that both varieties were good hosts for ST13, but RP1was better for ST16 and ST53. ; Acknowledgment This work has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement N. 727987 "Xylella fastidiosa Active Containment Through a multidisciplinary-Oriented Research Strategy XF-ACTORS" and FAPESP-Sao Paulo State Research Foundation (Proj. # 2013/10957-0)

Xylella fastidiosa is able to colonise a very large number of plant species, but considering each subspecies/phylogenetic clade the number of associated susceptible hosts is significantly reduced. Although strains genetically related most likely share similar host range, using phylogenetic relationships to infer information regarding the potential host range of new strains is still problematic, and pathogenicity tests remain the only means to assess the capability of a given strain to infect or not a specific plant species. Based on the current European legislative provisions on X. fastidiosa, information on the host range of the strain(s) causing an outbreak have regulatory consequences. In this context, we have made efforts to prove experimentally the capability of X. fastidiosa subsp. pauca, ST53, one of the most virulent European genotypes, to infect grapes, using 23 grape varieties (Vitis vinifera) and four rootstocks. Upon needle inoculation, plants were monitored for 18 months, using standand diagnostic methods (qPCR and isolation), supported by vector-transmission tests and observation of thin sections of the inoculated stems, stained using the LIVE/DEAD BacLight kit. qPCR assays on samples collected at the inoculation points (i.p.) and from the distal portions, 6 and 12 months post-inoculation, yielded positive reactions in more than 90% of the i.p., whereas in half of the cultivars scattered amplifications (the majority yielding Cq values > 30) occurred in some replicates at 15–20 cm from the i.p., but none of the apical portions tested positive. Isolations made 18 months after the inoculation, either from mature leaf petioles and stems portions harbouring the inoculation points, failed to recover actively growing colonies. At the same time, microscope observation of the thin sections showed only the presence of aggregates of dead Xylella-cells at the i.p. Transmission tests performed using specimens of Philaenus spumarius caged on the inoculated grapes produced negative results for both insects and ...

X. fastidiosa subsp. pauca causes diseases in citrus and olive plants. Fortunately, there are citrus species and olive varieties more tolerant to X. fastidiosa and therefore good genotypes to search for genetic sources of resistance. Following this approach, global gene expression analyses were recently achieved using Citrus reticulata cv. Ponkan and Olea europaea cv. Leccino allowing the identification of potential genes involved in plant defense response. Thus, the objective of this work was to identify key genes involved in common genetic defense responses that could be further explored to get resistant varieties. Overall we identified two main mechanisms for both plant species: i. Bacteria recognition and ii. Cell wall fortification. The former involve the expression of patternrecognition receptors, which recognize pathogen molecular patterns and trigger cell defense responses. Some of these receptors belong to the LRR-XII group which contains cell surface immune receptors. The latter involves downregulation of genes in tolerant host such as expansin, pectate lyases and polygalacturonases, related with cell wall expansion and degradation. This suggests that in tolerant hosts, plant cell recognizes X. fastidiosa and reprograms the cell wall development to impair its colonization through the xylem vessels. Therefore these genes represent good candidates to be explored aiming their use in breeding and/or genetic engineering program. Giampetruzzi A., Morelli M., Saponari M., Loconsole G., Chiumenti M., Boscia D., Savino V.N., Martelli G.P. & Saldarelli P. 2016. Transcriptome profiling of two olive cultivars in response to infection by the CoDiRO strain of Xylella fastidiosa subsp. pauca. BMC Genomics 17:475. Rodrigues C.M., De Souza A.A., Takita M.A., Kishi L.T. & Machado M.A. 2013. RNA-Seq analysis of Citrus reticulata in the early stages of Xylella fastidiosa infection reveals auxin-related genes as a defense response. BMC Genomics 14: 676. ; This work has received funding from the European Union's ...

Realizzato nell'ambito del progetto "Ricerca ed Innovazione per l'Olivicoltura Meridionale", finanziato dal MiPAAF ; Olive as other woody perennial crops can be affected by several systemic pathogens, including bacteria, fungi and several vector-borne viruses. The most important olive diseases, caused by different pathogens, are described in this text. Pathogen biology, diagnostic technique and control strategies are reported for each disease. The main and widespread bacterial disease, caused by Pseudomonas savastanoi pv. savastanoi, is the olive knot. As concerns the most important and widespread fungal diseases, in this text are described the olive leaf spot, Verticillum wilt, cercosporiosis, anthracnose, fruit rot, parasitic brusca, root rot, sooty mold and wood rot. Infections caused by viruses are generally symptomless and do not result in diseased plants. Although, viruses do not cause detrimental disease on olive varieties, the infected olive trees represent a reservoir of virus inoculum for other crops, where these viruses are known to cause severe disease. Detection of these viruses represent an important critical step in the sanitary improvement of this crop. Recently, molecularbased assays have been effectively implemented to detect at least 8 of the 15 viruses known to infect this crop. Sanitation program using in vitro culture of shoot tip and thermotherapy have been recently described to recover virus-free plantlets. ; MiPAAF - Ministero delle politiche agricole alimentari e forestali

A large program of mechanical inoculations and vector-mediated transmission experiments was launched in the past 2 years, and continuously implemented, in the attempt to disclose the role of the olive-infecting strain of X. fastidiosa in the olive quick decline disease (OQDS) and to ascertain the crop species under threat due to the expansion of the severe epidemic in southern Italy. Artificial inoculations were performed using the selected olive strain "De Donno" on different olive and grape cvs, stone fruit and citrus species, and ornamentals. These plant species, but including a larger number of olive cultivars, were also tested through field experiments set in the demarcated infected area, by exposing Xylella-free plants to the natural inoculum pressure and/or by caging naturally infected Philaenus spumarius. Comparison of the bacterial infection rates recovered upon mechanical inoculations and vector transmission (field experiments), showed perfect agreement regarding the susceptibility of the different host species: (i) high rates of systemically infected plants were obtained for olives, with some differences in relation to the cultivars, oleanders and Poligala myrtifolia; (ii) very low host colonization occurred for cherry and almond plants; (iii) no bacterial movement and host colonization could be detected in grapes, citrus, apricot, peach and plum. The pathogenicity of this strain has been also demonstrated; severe symptoms were detected on the most susceptible hosts. Acknowledgment This work was supported by the European Food Safety Authority (EFSA) in the framework of the "Pilot project on X. fastidiosa to reduce risk assessment uncertainties" (NP.EFSA.ALPHA.2014.07) and by the European Union's Horizon 2020 Research and Innovation Programme, under grant agreement No. 635646, POnTE (Pest Organisms Threatening Europe).

© 2016, Koninklijke Nederlandse Planteziektenkundige Vereniging. After the first confirmed outbreak of Xylella fastidiosa in the European Union (EU), associated with an olive disease denoted olive quick decline syndrome, mandatory surveys are now carried out in the member States and inspections increased at EU entry points such as ports. Such activities led to the interception of X. fastidiosa-infected coffee plants in consignments originating from Central America. Similarly, the geographic expansion of the olive decline epidemic area of the Apulia region (southern Italy) prompted investigations to identify new host plants. Here we report the interception of three novel bacterial sequence types in Italy, based on multi-locus sequence typing, that cluster with different X. fastidiosa subspecies, illustrating the risk of the introduction of additional pathogen genetic diversity into Europe. In the epidemic area of Apulia, new foci as well as host plant species positive with X. fastidiosa, including cherry, myrtleleaf and rosemary, were found to be all infected with the same sequence type of this bacterium (ST53, or CoDiRO strain). This work highlights the limited knowledge of X. fastidiosa phylogenetic and phenotypic diversity, the risk of novel X. fastidiosa introductions via contaminated plant material, and corroborates other studies indicating that the Apulia epidemic emerged from a single introduction of this pathogen into the region.

After the first confirmed outbreak of Xylella fastidiosa in the European Union (EU), associated with an olive disease denoted olive quick decline syndrome, mandatory surveys are now carried out in the member States and inspections increased at EU entry points such as ports. Such activities led to the interception of X.fastidiosa-infected coffee plants in consignments originating from Central America. Similarly, the geographic expansion of the olive decline epidemic area of the Apulia region (southern Italy) prompted investigations to identify new host plants. Here we report the interception of three novel bacterial sequence types in Italy, based on multi-locus sequence typing, that cluster with different X. fastidiosa subspecies, illustrating the risk of the introduction of additional pathogen genetic diversity into Europe. In the epidemic area of Apulia, new foci as well as host plant species positive with X.fastidiosa, including cherry, myrtleleaf and rosemary, were found to be all infected with the same sequence type of this bacterium (ST53, or CoDiRO strain). This work highlights the limited knowledge of X. fastidiosa phylogenetic and phenotypic diversity, the risk of novel X. fastidiosa introductions via contaminated plant material, and corroborates other studies indicating that the Apulia epidemic emerged from a single introduction of this pathogen into the region.

So far no effective field applicable therapeutic strategy exists to combat the severe diseases associated to X. fastidiosa. Therefore, various experimental applications to seek for a sustainable approach for the mitigation of the impact of the infections on olive trees were explored. In 2015-2016, four field trials were set in the infected area in southern Italy: (i) trial 1 consisted of an olive grove with medium to high incidence of disease symptoms; (ii) trials 2 and 3 consisted of olive groves with very low incidence of infected and symptomatic trees and (iii) trial 4 was a new plantation with 3-years old Xylella-free olive plants. Applications included (i) different elicitors of plant resistance (fosetyl aluminium, acibenzolar-S-methyl, COS-OGA, σ–β Hairpin proteins, cerevisanae) and (ii) Nacetylcysteine (NAC), a mucolytic agent previously showed to have a beneficial impact in reducing symptoms associated to X. fastidiosa in citrus (1). Periodic surveys included (i) sampling for laboratory tests to determine the incidence of the infections; (ii) symptom scoring using 0-5 empirical scale of severity. The overall results showed that only the treatments with NAC, through endotherapy and/or complexed to organic substances added to the soil, determined a noticeable amelioration of the symptoms. None of the elicitors produced any measurable positive impact on the diseased trees. These preliminary encouraging results, prompted for further targeted experiments currently ongoing. ; Acknowledgment This work has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement N. 635646 "Pest Organisms Threatening Europe POnTE" and from the Project T.A.P.A.S.S. (Tecnologie Abilitanti per Produzioni Agroalimentari Sicure e Sostenibili), Regione Puglia, Cluster Tecnologici Regionali.