30 results on '"Maria SAPONARI"'
Search Results
2. Xylella fastidiosa subsp. pauca <scp>ST53</scp> exploits pit membranes of susceptible olive cultivars to spread systemically in the xylem
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Vito Montilon, Angelo De Stradis, Maria Saponari, Raied Abou Kubaa, Annalisa Giampetruzzi, Giusy D'Attoma, and Pasquale Saldarelli
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Genetics ,Plant Science ,Horticulture ,Agronomy and Crop Science - Published
- 2022
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3. The impact of xylem geometry on olive cultivar resistance to Xylella fastidiosa: an image‐based study
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Nancy C. Walker, Steven M. White, Dan McKay Fletcher, Siul A. Ruiz, Kathryn E. Rankin, Angelo De Stradis, Maria Saponari, Katherine A. Williams, Chiara Petroselli, and Tiina Roose
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Biology and Microbiology ,Genetics ,Plant Science ,Horticulture ,Agronomy and Crop Science - Abstract
Xylella fastidiosa is a xylem-limited plant pathogen infecting many crops globally and is the cause of the recent olive disease epidemic in Italy. One strategy proposed to mitigate losses is to replant susceptible crops with resistant varieties. Several genetic, biochemical and biophysical traits are associated to X. fastidiosa disease resistance. However, mechanisms underpinning resistance are poorly understood. We hypothesize that the susceptibility of olive cultivars to infection will correlate to xylem vessel diameters, with narrower vessels being resistant to air embolisms and having slower flow rates limiting pathogen spread. To test this, we scanned stems from four olive cultivars of varying susceptibility to X. fastidiosa using X-ray computed tomography. Scans were processed by a bespoke methodology that segmented vessels, facilitating diameter measurements. Though significant differences were not found comparing stem-average vessel section diameters among cultivars, they were found when comparing diameter distributions. Moreover, the measurements indicated that although vessel diameter distributions may play a role regarding the resistance of Leccino, it is unlikely they do for FS17. Considering Young–Laplace and Hagen–Poiseuille equations, we inferred differences in embolism susceptibility and hydraulic conductivity of the vasculature. Our results suggest susceptible cultivars, having a greater proportion of larger vessels, are more vulnerable to air embolisms. In addition, results suggest that under certain pressure conditions, functional vasculature in susceptible cultivars could be subject to greater stresses than in resistant cultivars. These results support investigation into xylem morphological screening to help inform olive replanting. Furthermore, our framework could test the relevance of xylem geometry to disease resistance in other crops.
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- 2023
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4. Pest risk analysis on Xylella fastidiosa in Morocco
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Maria Saponari, Anna Maria D’Onghia, Mohamed Afechtal, and Antonio Vicent
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Xylella fastidiosa ,biology ,Botany ,Plant culture ,Soil Science ,Outbreak ,Plant Science ,Pest Risk Analysis ,pest risk analysis ,biology.organism_classification ,Agronomy and Crop Science ,SB1-1110 - Abstract
Morocco is basically an agricultural country; almost 40% of the workforce is employed in this sector. Xylella fastidiosa is a xylem-inhabiting pathogen which can infect more than 300 plant species, although most host species are symptomless. Until relatively recently, X. fastidiosa was primarily limited to North and South America, but in 2013 a widespread epidemic of olive quick decline syndrome caused by this fastidious pathogen appeared in southeastern Italy, and later several cases of X. fastidiosa outbreaks have been reported in other European countries (France, Germany and Spain). Following these recently confirmed findings of X. fastidiosa in the European Union, this bacterium has become a serious threat to the Moroccan flora. The national phytosanitary authorities have adopted several measures to prevent the introduction of X. fastidiosa into the national territory by deciding, inter alia, to suspend importation of host plant species to the bacterium from infected areas. This paper presents the phytosanitary risk of this bacterium in Morocco.
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- 2023
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5. Bioecological traits of spittlebugs and their implications on the epidemiology and control of Xylella fastidiosa epidemic in Apulia (Southern Italy)
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Nicola Bodino, Vincenzo Cavalieri, Crescenza Dongiovanni, Maria Saponari, and Domenico Bosco
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Plant Science ,Agronomy and Crop Science - Abstract
Spatial-temporal dynamics of spittlebug populations, together with transmission biology, are of major importance to outline the disease epidemiology of Xylella fastidiosa (Xf) subsp. pauca in Apulian olive groves. The spread rate of Xf is mainly influenced by (i) the pathogen colonization of the host plant; (ii) the acquisition of the pathogen by the vector from an infected plant, and its inoculation to healthy plants; (iii) the vector population dynamics and abundance at different spatial scales; (iv) the dispersal of the vector. In this contribution we summarize the recent advances in research on insect vectors’ traits – points (ii), (iii), (iv) – focusing on those most relevant to Xf epidemic in Apulia. Among the vectors’ bioecological traits influencing Xf epidemic on olive trees, we emphasize: natural infectivity and transmission efficiency, phenological timing of both nymphal and adult stage, the role of semi-natural vegetation as vectors’ reservoir in the agroecosystem and landscape, preferential and directional dispersal capabilities. Despite the research on Xf vectors carried out in Europe in the last decade, key uncertainties on insect vectors remain, hampering a thorough understanding of pathogen epidemiology and the development of effective and targeted management strategies. Our goal is to provide a structured and contextualized review of knowledge on Xf vectors’ key traits in Apulian epidemic, highlighting information gaps and stimulating novel research pathways on Xf pathosystems in Europe.
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- 2023
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6. Detection of Xylella fastidiosa in Host Plants and Insect Vectors by Droplet Digital PCR
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Serafina Serena Amoia, Angelantonio Minafra, Angela Ligorio, Vincenzo Cavalieri, Donato Boscia, Maria Saponari, and Giuliana Loconsole
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droplet digital PCR ,ddPCR ,qPCR ,Xylella fastidiosa ,quarantine pest ,molecular diagnosis ,Plant Science ,Agronomy and Crop Science ,Food Science - Abstract
Xylella fastidiosa (Xf) is a Gram-negative plant bacterium that causes severe diseases affecting several economically important crops in many countries. To achieve early detection of the pathogen, a droplet digital PCR (ddPCR)-based approach was used to detect the bacterium at low concentrations in different plant species and insect vectors. In this study, we implemented the reaction conditions of a previously developed ddPCR assay, and we validated its use to detect Xf in insect vectors as well as in a broader list of host species. More specifically, the sensitivity and accuracy of the protocol were assessed by testing five plant matrices (Olea europaea, Nerium oleander, Vitis vinifera, Citrus sinensis, and Prunus dulcis), and for the first time, the insect vector (Philaenus spumarius), was either naturally infected or artificially spiked with bacterial suspension at known concentrations. The lowest concentrations detected by ddPCR were 5 ag/µL of bacterial DNA and 1.00 × 102 CFU/mL of bacterial cells. Both techniques showed a high degree of linearity, with R2 values ranging from 0.9905 to 0.9995 and from 0.9726 to 0.9977, respectively, for qPCR and ddPCR. Under our conditions, ddPCR showed greater analytical sensitivity than qPCR for O. europea, C. sinensis, and N. oleander. Overall, the results demonstrated that the validated ddPCR assay enables the absolute quantification of Xf target sequences with high accuracy compared with the qPCR assay, and can support experimental research programs and the official controls, particularly when doubtful or inconclusive results are recorded by qPCR.
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- 2023
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7. The Detection of viruses in olive cultivars in Greece, using a rapid and effective RNA extraction method, for certification of virus-tested propagation material
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Toufic Elbeaino, Georgios Koubouris, Maria Saponari, Matthaios M. Mathioudakis, and Beata Hasiów-Jaroszewska
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virus-tested propagation material ,RT-PCR ,Olive viruses ,Plant Science ,Certification ,Horticulture ,Biology ,Virus ,lcsh:QK1-989 ,lcsh:Botany ,Cultivar ,RNA extraction ,olive RNA extraction protocol ,Agronomy and Crop Science - Abstract
Although Greece is the world’s third largest olive production country, information about the presence of olive viruses is limited. A survey for the presence of virus infections in the ten most important Greek cultivars was conducted in a germplasm collection olive grove located in Chania, Crete. Samples were RT-PCR assayed for the presence of Arabis mosaic virus (ArMV), Cherry leafroll virus (CLRV), Strawberry latent ring spot virus (SLRSV), and Olive leaf yellowing-associated virus (OLYaV), amplifying part of the capsid protein (ArMV), the 3΄UTR (CLSRV, SLRSV) or the HSP70h (OLYaV) gene. Total RNAs were purified using the Trizol method, yielding good quality and purity, thereby confirming application of the method as a rapid economic extraction protocol for detection of olive viruses. SLRSV was the most predominant virus, with an infection rate of 55%, followed by CLRV and OLYaV in 5% of the tested samples. ArMV was detected only in one sample. Mixed virus infections were also commonly detected. The DNA amplicons of the obtained viruses from the infected samples were sequenced. The partial sequences of ArMV, CLRV and SLRSV from olives, which are reported for the first time, showed 74-100% nucleotide similarity with available homologous sequences from other crops, whereas OLYaV isolates showed high sequence variability of 25%. The phylogenetic analysis based on olive-OLYaV HSP70h partial-nucleotide sequences grouped the olive isolate sequences according to the geographical origins of the host germplasm collection. This is the first official report of the occurrence of olive viruses in Greece, emphasizing the need to implement a certification programme for production and distribution of high-quality (virus-free) olive propagation material, in Greece and more generally in the Mediterranean basin.
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- 2020
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8. Attempts to Reduce the Systemic Spread of Xylella fastidiosa in Olive Trees by Pruning
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Salvatore Camposeo, Gaetano Alessandro Vivaldi, and Maria Saponari
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disease management ,olive ,heading ,thinning ,pruned biomass ,Agronomy and Crop Science - Abstract
Xylella fastidiosa subsp. pauca (Xfp) is the plant pathogenic bacterium causing the epidemic of olive quick decline syndrome decimating olive trees in the Apulia region (southern Italy). The lack of any effective therapeutic application for the control of this pathogen and its categorization as a regulated quarantine pathogen in many countries worldwide, impose mandatory eradication and containment measures. Based on current EU legislation, containment measures apply in those areas where the bacterium is widely established, such as in the Apulia region, and thus containment strategies to mitigate and cope with the infections are needed. We set up a field trial to assess if pruning interventions could limit and/or recover Xfp-infected trees by reducing the systemic spread of the bacterium and the severity of the desiccation phenomena typically compromising the crown of the highly susceptible cultivars, e.g., cv. Cellina di Nardò. Trees subjected either to major or light pruning interventions, including the removal of all the symptomatic branches, did not demonstrate a reduced bacterial colonization or development of symptoms. After two years of targeted pruning interventions, no significant amelioration of the sanitary status of the infected olive trees was recorded, suggesting that the sole application of these interventions is not effective to counteract the impact of the bacterium in the susceptible olive trees.
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- 2022
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9. Diagnostic Procedures to Detect Xylella fastidiosa in Nursery Stocks and Consignments of Plants for Planting
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Lorenzo Manco, O. Potere, Stefania Zicca, Maria Saponari, Giuliana Loconsole, Giuseppe Altamura, Vito Elicio, Oumaima El Hatib, Franco Valentini, and Donato Boscia
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sampling ,consignments ,biology ,Host (biology) ,Agriculture (General) ,Outbreak ,food and beverages ,Plant Science ,laboratory tests ,biology.organism_classification ,Polygala myrtifolia ,S1-972 ,Horticulture ,Prunus ,composite samples ,nursery stocks ,Xylella fastidiosa ,inspection ,Agronomy and Crop Science ,Lavandula stoechas ,Solanaceae ,nursery stock ,Food Science ,Phytosanitary certification - Abstract
Preventive measures for infectious diseases caused by the harmful plant pathogenic bacterium Xylella fastidiosa include inspections and diagnostic tests on imported consignments of plants and in nurseries. Currently, mandatory checks on plant propagating materials are enforced in Europe (EU regulation 2021/1201) for the most susceptible species found in the European outbreaks, and prior to move propagating materials of the “specified plants” from nurseries located in the so-called “demarcated areas”. These requirements imply sampling and laboratory manipulation of a large number of samples, nevertheless plants to be sampled are often small size potted plants. While statistically based methods for inspections and sampling are available, namely the International Standards for Phytosanitary Measures n. 31, validated laboratory procedures to test large volumes of plant materials are lacking. In this work, we optimized two distinct protocols to detect X. fastidiosa in pooled plant materials collected from lots of plants for planting. The first protocol was designed to test in pool few samples (up to 8), the second to process through a single diagnostic test plant material from a high number of samples (up to 225). Accuracy of the newly developed protocols was assessed by pooling at different ratio tissues collected from healthy and infected Polygala myrtifolia, Nerium oleander, Olea europaea, Lavandula stoechas and Prunus avium. Moreover, tests included pools of plantlets of Brassicaceae and Solanaceae artificially inoculated with stem portions of infected periwinkle. Using both protocols, high diagnostic sensitivity values were generated using serological and molecular tests, with qPCR consistently yielding the highest performance values, regardless the host species tested.
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- 2021
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10. Occurrence and Distribution of Major Viruses Infecting Eggplant in Lebanon and Molecular Characterization of a Local Potato Virus X Isolate
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Fabrizio Cillo, Angelo De Stradis, Elia Choueiri, Raied Abou Kubaa, Maria Saponari, and Fouad Jreijiri
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0106 biological sciences ,Veterinary medicine ,eggplant ,RT-PCR ,Plant Science ,01 natural sciences ,PVX ,Virus ,PVY ,Pepper mottle virus ,Cucumber mosaic virus ,03 medical and health sciences ,Lebanon ,lcsh:Agriculture (General) ,030304 developmental biology ,Phytosanitary certification ,0303 health sciences ,biology ,Spots ,fungi ,CMV ,food and beverages ,biology.organism_classification ,Potato virus X ,lcsh:S1-972 ,EMDV ,Alfalfa mosaic virus ,Potato virus Y ,Agronomy and Crop Science ,Solanum melongena ,010606 plant biology & botany ,Food Science - Abstract
This research was carried out in order to evaluate the presence and distribution of viral infections causing severe disease in eggplant plants collected from different districts in Bekaa valley, Lebanon. Most infected plants showed virus-like symptoms consisting predominantly of leaf blotch, mottling chlorotic and ring spots, leaf twisting and plant dwarf were also observed in the visited fields. Symptomatic and asymptomatic plants were collected and screened by ELISA test for the presence of several different pathogenic viruses potentially present in the area. Results showed that potato virus Y (PVY) was the most prevalent virus found by ELISA (detected in the 15.3% of the tested plants), followed by eggplant mottled dwarf virus (EMDV, 2.9%) and cucumber mosaic virus (CMV, 1.2%), while tomato spotted wilt virus (TSWV), alfalfa mosaic virus (AMV) and pepper mottle virus (PepMoV) were not detected. Biological indexing of symptomatic ELISA-negative plants, followed by electron microscopy, indicated the presence of virus-like particles of the genus Potexvirus, which was subsequently confirmed as potato virus X (PVX) by RT-PCR and Sanger sequencing. PVX was found in 35.3% of the tested plants, all sampled in the northern Bekaa area. In a phylogenetic analysis, the partial coat protein gene sequence of a selected Lebanese isolate, PVX-AK1, clustered together with other PVX isolates from Asia. Furthermore, the 124-aa sequence of PVX-AK1 shared 100% identity with PVX-UK3, an isolate which is known as avirulent in potato genotypes carrying either Nx or Rx resistance genes. This work revealed a picture of the previously uninvestigated phytosanitary status of eggplant crops in an important horticultural area of Lebanon.
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- 2021
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11. A possible role of CTV.20 gene methylation in response to Citrus tristeza virus infection
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Valentina Fanelli, Luigi Ricciardi, P Leonetti, Cinzia Montemurro, Maria Saponari, and C. De Giovanni
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0106 biological sciences ,0301 basic medicine ,Genetics ,Citrus ,Candidate gene ,biology ,Citrus tristeza virus ,Locus (genetics) ,Plant Science ,Horticulture ,biology.organism_classification ,01 natural sciences ,Virology ,Citrange ,CTV.20 gene methylation ,03 medical and health sciences ,030104 developmental biology ,Rutaceae ,Plant virus ,DNA methylation ,CTV ,RNA silencing ,Agronomy and Crop Science ,Gene ,010606 plant biology & botany - Abstract
Citrus tristeza virus (CTV) is the pathogen causing tristeza diseases in several Rutaceae species and leading to significant economic damage to citrus worldwide. The Ctv locus provides broad spectrum resistance to CTV in Poncirus trifoliata L. Raf. This locus is present also in tolerant and susceptible species, so an epigenetic mechanism of Ctv expression regulation was proposed. Indeed, a difference in plant 24-nt sRNAs distribution corresponding to CTV.20 gene was previously observed in susceptible species following CTV infection. This gene, encoding for a plant virus movement-like protein, was investigated as a candidate gene for CTV susceptibility. Here, we show the presence of differences in methylation status of a specific region of CTV.20 in two susceptible species, sour and sweet orange, following CTV infection. On the contrary, no significant differences were observed in the tolerant Citrange carrizo following the infection. Moreover, a hypermethylation of the whole CTV.20 gene was observed in Citrange carrizo both healthy and infected, and in healthy sour and sweet orange. This preliminary study allows hypothesizing a possible role of methylation in regulation of CTV.20 expression involved in the CTV susceptibility.
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- 2017
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12. First Report of 'Candidatus Liberibacter asiaticus' Associated with Huanglongbing in Sweet Orange in Ethiopia
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G. De Bac, L. Catalano, J. Breithaupt, R. K. Yokomi, Maria Saponari, and Giuliana Loconsole
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Candidatus Liberibacter asiaticus ,Candidatus Liberibacter ,Plant Science ,Orange (colour) ,Biology ,Disease distribution ,Liberibacter asiaticus ,biology.organism_classification ,Trioza erytreae ,Heat sensitive ,Horticulture ,Botany ,Orchard ,Agronomy and Crop Science - Abstract
Huanglongbing (HLB) is a serious disease of citrus worldwide. Three different ‘Candidatus Liberibacter’ species are associated with HLB: ‘Ca. Liberibacter asiaticus’, ‘Ca. L. africanus’, and ‘Ca. L. americanus’ (1). ‘Ca. L. africanus’ and its vector, Trioza erytreae, are both heat sensitive, and when present, occur in citrus when temperatures remain below 30 to 32°C. In Africa, ‘Ca. L. africanus’ and T. erytreae have been reported in South Africa, Zimbabwe, Malawi, Burundi, Kenya, Somalia, Ethiopia, Cameroon, and Madagascar (1). Inspection of citrus trees in orchards and budwood sources in nurseries located in the warmer citrus-growing areas of Tigray and North Wollo in northern Ethiopia revealed nearly 100 trees with symptoms of leaf yellowing with a blotchy mottle pattern, dead branches, and decreased fruit quality and yield. Two symptomatic sweet orange budwood trees and three symptomatic orchard plants were sampled in April 2009, along with three healthy-looking sweet orange plants. DNA was extracted from 200 mg of desiccated leaf midribs using the CTAB method (4) and subjected to conventional PCR using the primer pairs A2/J5 (2) and OI2/23S1 (3) that amplify the ribosomal protein gene in the rplKAJL-rpoBC operon and the 16S/23S ribosomal intergenic regions, respectively, of ‘Ca. L. africanus’ and ‘Ca. L. asiaticus’. Positive PCR reactions were obtained for all five symptomatic samples with both primer pairs. PCR amplicons of 703 bp (A2/J5) and 892 bp (OI2/23S) recovered from two of these samples were purified, cloned, and sequenced. BLAST analysis revealed that the nucleotide sequences we obtained for the ribosomal protein (GenBank Accessions Nos. GQ890155 and GQ890156) shared 100% identity with each other and 99% identity with sequences of ‘Ca. L. asiaticus’ from Brazil (DQ471904), Indonesia (AB480161), China (DQ157277), and Florida (CP001677). Similarly, the 16S/23S ribosomal intergenic sequences (GU296538 and GU296539) shared 100% identity with each other and 99% identity with homologous ‘Ca. L. asiaticus’ sequences from Brazil (DQ471903), Indonesia (AB480102), China (DQ778016), and Florida (CP001677) and contained two tRNA genes as occurs in ‘Ca. L. asiaticus’ but not in ‘Ca. L. africanus’ (3). To our knowledge, this is the first report of ‘Ca. L. asiaticus’ in Africa. The presence of ‘Ca. L. asiaticus’ is a threat for warmer citrus-growing areas of Africa that are less favorable for ‘Ca. L. africanus’ and T. erytreae. In areas where ‘Ca. L. asiaticus’ was confirmed, symptomatic trees must be promptly eradicated and surveys to determine spread of the disease and its vectors are necessary. References: (1) J. M. Bove. J. Plant Pathol. 88:7, 2006. (2) A. Hocquellet et al. Mol. Cell. Probes 13:373, 1999. (3) S. Jagoueix et al. Int. J. Syst. Bacteriol. 47:224, 1997. (4) M. G. Murray and W. F Thompson. Nucleic Acids Res. 8:4321, 1980.
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- 2019
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13. Draft Genome Resources of Two Strains ('ESVL' and 'IVIA5901') of Xylella fastidiosa Associated with Almond Leaf Scorch Disease in Alicante, Spain
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Maria Saponari, Ester Marco-Noales, Inmaculada Navarro, Blanca B. Landa, Pasquale Saldarelli, Rodrigo P. P. Almeida, Miguel Montes-Borrego, Miguel Román-Écija, María Pilar Velasco-Amo, Donato Boscia, Annalisa Giampetruzzi, Silvia Barbé, Vito Nicola Savino, Vito Montilon, Adela Monterde, European Commission, European Cooperation in Science and Technology, Ministerio de Ciencia, Innovación y Universidades (España), and National Institutes of Health (US)
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0106 biological sciences ,0301 basic medicine ,Sequence analysis ,Genomics ,Plant Science ,Subspecies ,leaf scorch ,Xylella ,01 natural sciences ,Genome ,DNA sequencing ,03 medical and health sciences ,Phylogenetics ,Phylogeny ,Plant Diseases ,Xylella fastidiosa ,2. Zero hunger ,Genetics ,biology ,Phylogenetic tree ,Sequence Analysis, DNA ,biology.organism_classification ,Prunus dulcis ,Europe ,030104 developmental biology ,Spain ,Agronomy and Crop Science ,010606 plant biology & botany - Abstract
An outbreak of Xylella fastidiosa subsp. multiplex sequence type ST6 was discovered in 2017 in mainland Spain affecting almond trees. Two cultured almond strains, “ESVL” and “IVIA5901,” were subjected to high throughput sequencing and the draft genomes assembled. Phylogenetic analysis conclusively indicated they belong to the subspecies multiplex, and pairwise comparisons of the chromosomal genomes showed an average nucleotide identity higher than 99%. Interestingly, the two strains differ for the presence of the plasmids pXF64-Hb_ESVL and pUCLA-ESVL detected only in the ESVL strain. The availability of these draft genomes contribute to extend the European genomic sequence dataset, a first step toward setting new research to elucidate the pathway of introduction and spread of the numerous strains of this subspecies so far detected in Europe., This work was funded by European Union’s Horizon 2020 Framework Research Programme Projects XF-ACTORS (Xylella fastidiosa Active Containment Through a Multidisciplinary-Oriented Research Strategy grant 727987) and MSCA-RISE-2016 CURE-XF (Capacity Building and Raising Awareness in Europe and in Third Countries to Cope with Xylella fastidiosa); COST Action CA16107 EuroXanth, supported by European Cooperation in Science and Technology; and Project Desarrollo de estrategias de erradicación, contención y control de en España: Diagnóstico, estructura genética y gama de huéspedes project E-RTA2017-00004-C06-02 from Programa Estatal de I+D+I Orientada a los Retos de la Sociedad of the Spanish Government. This work used the Vincent J. Coates Genomics Sequencing Laboratory at University of California, Berkeley, supported by NIH S10 OD018174 Instrumentation Grant.
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- 2019
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14. A new variant of Xylella fastidiosa subspecies multiplex detected in different host plants in the recently emerged outbreak in the region of Tuscany, Italy
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Giusy D’Attoma, Giuseppe Altamura, Maria Saponari, Giuliana Loconsole, Domenico Rizzo, Donato Boscia, Raied Abou Kubaa, and Stefania Zicca
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0106 biological sciences ,0301 basic medicine ,Sequence type ,Zoology ,Genomics ,Plant Science ,Horticulture ,Subspecies ,01 natural sciences ,03 medical and health sciences ,Genotype ,Pathogen ,Xylella fastidiosa ,biology ,Outbreak ,Xylella fastidiosa Tuscany MLST Sequence type Host plants ,biology.organism_classification ,Olive trees ,030104 developmental biology ,Tuscany ,Multilocus sequence typing ,Host plants ,Agronomy and Crop Science ,010606 plant biology & botany ,MLST - Abstract
The vector-borne bacterial pathogenXylella fastidiosais widely distributed in the Americas; in the last decade it has emerged as a serious threat for agricultural crops, natural environment and landscape in Europe. Following the first EU outbreak in 2013 in southern Italy, associated with a severe disease in olive trees, annual mandatory surveys are now in place in the Member States, leading to the discovery of bacterial outbreaks in different countries. Among the latest findings, an outbreak has been reported in the Italian region of Tuscany, with infections identified in seven different plant species. In this work, we report the isolation and the genetic characterization of isolates associated with this newly discovered outbreak. Multilocus sequence typing approach revealed the occurrence of isolates harbouring a new sequence type, denoted ST87, genetically related to strains of subsp.multiplex, but different from the genotypes of this subspecies previously characterized in Europe. Five cultured strains were successfully recovered from four of the seven host plants, an important achievement for advancing the studies on genomics and pathogenicity of theseisolates and thus assess their potential threat for European agriculture.
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- 2019
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15. Draft Genome Sequence Resources of Three Strains (TOS4, TOS5, and TOS14) of Xylella fastidiosa Infecting Different Host Plants in the Newly Discovered Outbreak in Tuscany, Italy
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Stefania Zicca, Donato Boscia, Giusy D’Attoma, Pasquale Saldarelli, Annalisa Giampetruzzi, Maria Saponari, Domenico Rizzo, and Raied Abou Kubaa
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Whole genome sequencing ,Genetics ,Xylella fastidiosa ,Phylogenetic tree ,Outbreak ,Plant Science ,Subspecies ,Biology ,biology.organism_classification ,Genome ,multiplex ,ST87 ,Phylogenetics ,Multilocus sequence typing ,bacteriology ,Agronomy and Crop Science - Abstract
An outbreak of Xylella fastidiosa was discovered in late 2018 in northern Italy affecting several plant species. Multilocus sequence typing analyses detected the presence of strains clustering in X. fastidiosa subsp. multiplex and harboring a hitherto uncharacterized sequence type, ST87. Three cultured strains (TOS4, TOS5, and TOS14) were subjected to high-throughput sequencing and the draft genomes assembled. Phylogenetic analysis conclusively indicated that they belong to the subspecies multiplex. The genetic information generated for these newly discovered strains further supports the evidence that sequence types are associated with the emergence of X. fastidiosa in Europe, posing major challenges for predicting the main threatened European and Mediterranean crops and plant species.
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- 2019
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16. The olive quick decline syndrome in south-east Italy: a threatening phytosanitary emergency
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Francesco Porcelli, Maria Saponari, G. P. Martelli, and Donato Boscia
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0106 biological sciences ,0301 basic medicine ,Philaenus spumarius ,Plant Science ,Horticulture ,01 natural sciences ,Polygala myrtifolia ,law.invention ,03 medical and health sciences ,law ,Disease management ,Botany ,Quarantine ,media_common.cataloged_instance ,European union ,Phytosanitary certification ,media_common ,Myrtus communis ,biology ,Broom ,Spittlebugs ,biology.organism_classification ,030104 developmental biology ,Xylella fastidiosa subsp.pauca ,Xylella fastidiosa ,Agronomy and Crop Science ,010606 plant biology & botany - Abstract
The olive quick decline syndrome (OQDS) is a disease that appeared suddenly a few years ago in the province of Lecce (Salento peninsula, southeastern Italy). Among the factors that may be involved in its aetiology, the most relevant is Xylella fastidiosa, a quarantine pathogen of American origin, whose presence in Italy represents its first confirmed record in the European Union. X. fastidiosa is a Gram-negative bacterium that invades the xylem of a wide range of hosts, from which it is acquired by xylem-feeding insect vectors and transferred to other plants. The bacterium multiplies within the plant vessels and occludes them, thus impairing water uptake. Besides olive, the Salentian strain of X. fastidiosa infects in nature a number of woody (almond, cherry) and shrubby (oleander, broom, Acacia saligna, Polygala myrtifolia, Westringia fruticosa, Rosmarinus officinalis, Rhamnus elaternus, Myrtus communis) hosts, with no evidence for grapevines or citrus being hosts. The bacterium was isolated in culture and identified as a genotype of X. fastidiosa subsp. pauca, molecularly identical to an isolate from Costa Rica. Philaenus spumarius (meadow spittlebug), a froghopper quite common in the Salento area where it thrives on olive, was identified as the main vector. Disease eradication and sanitation of infected olives are unfeasible. However, strategies are being enacted for restraining the spread of pathogen and vector(s) within the boundaries of the currently infected zone.
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- 2015
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17. Development of real-time PCR based assays for simultaneous and improved detection of citrus viruses
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Maria Saponari, Vito Nicola Savino, Giuliana LOCONSOLE, and MARIA SAPONARI
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Citrus psorosis virus ,biology ,Serial dilution ,food and beverages ,Citrus tristeza virus ,Plant Science ,Horticulture ,biology.organism_classification ,Virology ,Citrus variegation virus ,law.invention ,law ,Plant virus ,TaqMan ,Multiplex ,Agronomy and Crop Science ,Polymerase chain reaction - Abstract
Citrus, one of the most economically important crops, is susceptible to a number of arthropod- and graft-transmissible pathogens. Rapid and reliable methods for detecting multiple pathogens are important for routine diagnosis by reducing time, labour and costs. To this end, primers and TaqMan probes for Citrus psorosis virus (CPsV) and Citrus variegation virus (CVV) detection by singleplex real-time (q) reverse transcription (RT)- PCR were initially designed. Further optimizations included the development of a multiplex (m) RT-qPCR assay to detect simultaneously CPsV, CVV, and Citrus tristeza virus (CTV) in a single reaction. When 10-fold serial dilutions prepared using total RNAs from CPsV- and CVV-infected plants were tested, RT-qPCR assays proved to be 100 and 1000 times more sensitive than conventional RT-PCR, respectively. The target viruses were effectively identified by mRT-qPCR in field-infected clementine and sweet orange trees. The optimized multiplex assay proved to be as sensitive as the singleplex tests, thus providing a valuable alternative tool for detection of these citrus viruses.
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- 2010
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18. Genome-Wide Analysis Provides Evidence on the Genetic Relatedness of the Emergent Xylella fastidiosa Genotype in Italy to Isolates from Central America
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Donato Boscia, Vito Nicola Savino, Rodrigo P. P. Almeida, Maria Saponari, Giuliana Loconsole, Annalisa Giampetruzzi, Carlos Chacón-Díaz, Pasquale Saldarelli, Stefania Zicca, Blanca B. Landa, and European Commission
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Crop and Pasture Production ,0301 basic medicine ,Costa Rica ,DNA, Bacterial ,Genotype ,Plant Biology & Botany ,030106 microbiology ,Plant Biology ,Plant Science ,Subspecies ,Xylella ,Microbiology ,Polymorphism, Single Nucleotide ,PAUCA ,03 medical and health sciences ,Monophyly ,GENOTIPO ,Botany ,Polymorphism ,Clade ,Phylogeny ,2. Zero hunger ,Genetics ,Genetic diversity ,Genome ,biology ,Phylogenetic tree ,Bacterial ,DNA ,Single Nucleotide ,Gene Expression Regulation, Bacterial ,biology.organism_classification ,Olive trees ,ST53 ,Gene Expression Regulation ,Italy ,Xylella fastidiosa ,Agronomy and Crop Science ,GENOMA" ,Genome, Bacterial ,Genome-Wide Association Study - Abstract
First, third, and fifth authors: Università degli Studi di Bari Aldo Moro, Dipartimento di Scienze del Suolo della Pianta e degli Alimenti, via Amendola 165/A, Bari, Italy; second, fourth, seventh, and tenth authors: Consiglio Nazionale delle Ricerche, Istituto per la Protezione Sostenibile delle Piante, Bari, via Amendola 122/D, Bari, Italy; sixth author: Department of Environmental Science, Policy and Management, University of California, Berkeley, CA, 94720-3114; eighth author: Institute for Sustainable Agriculture, Consejo Superior de Investigaciones Científicas, 14004 Córdoba, Spain; and ninth author: Centro de Investigación en Enfermedades Tropicales (CIET), Facultad de Microbiología, Universidad de Costa Rica, 2060 San José, Costa Rica., The work was supported by funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement 635646: POnTE (Pest Organisms Threatening Europe).
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- 2017
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19. Intercepted isolates of Xylella fastidiosa in Europe reveal novel genetic diversity
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G. P. Martelli, Giuliana Loconsole, Maria Saponari, Giusy D’Attoma, Rodrigo P. P. Almeida, M. Morelli, and Donato Boscia
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0106 biological sciences ,0301 basic medicine ,Crop and Pasture Production ,Plant Biology & Botany ,Plant Biology ,Plant Science ,Horticulture ,Biology ,Subspecies ,01 natural sciences ,Microbiology ,03 medical and health sciences ,media_common.cataloged_instance ,Typing ,European union ,Pierce's disease ,media_common ,vector-borne ,Xylella fastidiosa ,Genetic diversity ,Olive disease ,Phylogenetic tree ,Ecology ,Strain (biology) ,Outbreak ,biology.organism_classification ,030104 developmental biology ,Infection ,Agronomy and Crop Science ,010606 plant biology & botany - Abstract
© 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.
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- 2016
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20. Inter-laboratory validation of PCR-based protocol for detection of olive viruses
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Maria Nuzzaci, H. Bouyahia, F. Faggioli, Toufic Elbeaino, Maria Saponari, Alberto Materazzi, Giuliana Loconsole, V. A. Prota, G. Albanese, N. Trisciuzzi, Gianfranco Romanazzi, and Vito Nicola Savino
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Protocol (science) ,business.industry ,detection ,virus ,Plant Science ,Horticulture ,Biology ,Diagnostic tools ,Olive mild mosaic virus ,olive ,Biotechnology ,Virus identification ,Plant virus ,Specific primers ,Inter-laboratory ,business ,Agronomy and Crop Science ,Phytosanitary certification - Abstract
Sanitary selection and certification of olive cultivars require sensitive diagnostic methods and effective sanitation protocols. Although much attention has been paid in the past few years to the development of diagnostic tools for reliable virus identification, the need to define a common and standardized diagnostic protocol led to the implementation of a ring test among nine Italian diagnostic laboratories. A one-step RT-PCR protocol and different primer sets, targeting the most common olive viruses covered by phytosanitary rules, were tested in each laboratory, using the same batch of positive and healthy controls as well as the same amplification conditions and reaction components. The one-step RT-PCR, performed using several specific primer sets, was able efficiently to detect the target viruses in all laboratories. Furthermore, a one-step RT-PCR protocol was used successfully for the first time for detection of Tobacco necrosis virus (TNV) and Olive mild mosaic virus (OMMV). Results showed that all target viruses were not uniformly distributed in the canopy, and that at least two subsets of samples must be collected from each plant. This standardized protocol is now being used to produce nuclear stocks for 70 different Italian olive cultivars, in the framework of the national project OLVIVA, which involves 25 national research institutions.
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- 2010
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21. Rapid Differentiation and Identification of Potential Severe Strains of Citrus tristeza virus by Real-Time Reverse Transcription-Polymerase Chain Reaction Assays
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P. J. Sieburth, Raymond Yokomi, and Maria Saponari
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Citrus ,Genotype ,Plant Science ,decline ,strain differentiation ,Plant Viruses ,law.invention ,law ,Plant virus ,TaqMan ,Closterovirus ,Multiplex ,Polymerase chain reaction ,Plant Diseases ,biology ,Reverse Transcriptase Polymerase Chain Reaction ,seedling yellows ,Genetic Variation ,Citrus tristeza virus ,biology.organism_classification ,Virology ,Molecular biology ,Reverse transcriptase ,Reverse transcription polymerase chain reaction ,stem pitting ,Agronomy and Crop Science - Abstract
A multiplex Taqman-based real-time reverse transcription (RT) polymerase chain reaction (PCR) assay was developed to identify potential severe strains of Citrus tristeza virus (CTV) and separate genotypes that react with the monoclonal antibody MCA13. Three strain-specific probes were developed using intergene sequences between the major and minor coat protein genes (CPi) in a multiplex reaction. Probe CPi-VT3 was designed for VT and T3 genotypes; probe CPi-T36 for T36 genotypes; and probe CPi-T36-NS to identify isolates in an outgroup clade of T36-like genotypes mild in California. Total nucleic acids extracted by chromatography on silica particles, sodium dodecyl sulfate-potassium acetate, and CTV virion immunocapture all yielded high quality templates for real-time PCR detection of CTV. These assays successfully differentiated CTV isolates from California, Florida, and a large panel of CTV isolates from an international collection maintained in Beltsville, MD. The utility of the assay was validated using field isolates collected in California and Florida.
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- 2010
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22. Polymerase Chain Reaction-Based Detection of Spiroplasma citri Associated with Citrus Stubborn Disease
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A. F. S. Mello, Raymond Yokomi, Maria Saponari, and Jacqueline Fletcher
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Spiroplasma citri ,Serial dilution ,Plant Science ,Biology ,biology.organism_classification ,DNA extraction ,law.invention ,Microbiology ,Real-time polymerase chain reaction ,stomatognathic system ,law ,biology.protein ,Primer (molecular biology) ,Agronomy and Crop Science ,Pathogen ,Polymerase chain reaction ,Polymerase - Abstract
Yokomi, R. K., Mello, A. F. S., Saponari, M., and Fletcher, J. 2008. Polymerase chain reactionbased detection of Spiroplasma citri associated with citrus stubborn disease. Plant Dis. 92:253260. Polymerase chain reaction (PCR)-based detection of citrus stubborn disease was improved using primers based on sequences of the P89 putative adhesin gene and the P58 putative adhesin multigene of Spiroplasma citri. Real-time PCR also was developed with detection limits estimated to be between 10–4 and 10–4 ng by serial dilution of a recombinant S. citri plasmid into DNA extracts from healthy Madam Vinous sweet orange. PCR for the detection of S. citri by these new primers was validated by comparing culturing of the pathogen, the traditional method of diagnosis, with PCR assays from samples taken from two citrus plots in Kern County, CA. Fruit columella was collected from 384 and 377 individual trees in each of two fields, respectively; one portion was used for culturing and the other for DNA extraction and PCR. PCR results matched those of culturing 85 to 100% of the time depending on the primers used. More importantly, PCR detected S. citri from culture-negative trees in 5 to 15% of the cases, suggesting that PCR performed as well or better than culturing for detection of S. citri in field samples. Realtime PCR proved to be the best method for detection. Differential reaction of the samples to the P58 primer pairs suggested that two populations of S. citri occur in historical and present-day field isolates. Citrus stubborn disease incidence was estimated to be 58.3 and 3.7% in the two orchards. The results presented here support the use of PCR for reliable detection of S. citri in field trees. Additional keyword: epidemiology
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- 2008
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23. Preliminary evaluation of the status of olive-infecting viruses in Syria
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T. El Beaino, Michele Digiaro, H. Hallak, A. Al Abdullah, and Maria Saponari
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Veterinary medicine ,biology ,viruses ,Plant Science ,Horticulture ,biology.organism_classification ,Virology ,Virus ,Cherry leaf roll virus ,Arabis mosaic virus ,Cucumber mosaic virus ,Olive leaf ,Strawberry latent ringspot virus ,Plant virus ,Olive latent virus 2 ,Agronomy and Crop Science - Abstract
Field surveys of 80 commercial groves were made in autumn 2003 in six major Syrian olive-growing regions. A total of 300 olive samples, representative of the main cultivars grown in the country, were collected. As ascertained by dsRNA analysis, 54 out of 125 samples (about 43%) showed visible bands in polyacrylamide gel electrophoresis. All samples were tested by RT-PCR for the presence of the following viruses: Arabis mosaic virus (ArMV), Cherry leaf roll virus (CLRV), Cucumber mosaic virus (CMV), Olive latent ringspot virus (OLRSV), Olive latent virus 1 (OLV-1), Olive latent virus 2 (OLV-2), Olive leaf yellowing-associated virus (OLYaV) and Strawberry latent ringspot virus (SLRSV). All these viruses, singly or in mixed infection, were detected in about 51% of the samples. CMV was the most prevalent (22.7%), followed by CLRV (15%), OLYaV (14.3%) and OLRSV (11.5%). Less represented were the remaining four viruses. Infection rates ranged from 44%) in Dara'a region to 67% in Latakia and Hama.
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- 2005
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24. On the presence and distribution of olive viruses in Lebanon
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Michele Digiaro, C. Fadel, G. P. Martelli, T. El Beaino, Vito Nicola Savino, Maria Saponari, and E. Choueiri
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Veterinary medicine ,biology ,Plant Science ,Horticulture ,biology.organism_classification ,Virology ,Virus ,Cherry leaf roll virus ,Sadwavirus ,Arabis mosaic virus ,Strawberry latent ringspot virus ,Olive leaf ,Plant virus ,Closterovirus ,Agronomy and Crop Science - Abstract
A survey for viruses was carried out in 2003 in the main olive-growing areas of Lebanon (South Lebanon, North Lebanon, Mount Lebanon and Bekaa). A total of 300 samples was collected in 31 different locations in 76 different commercial orchards and checked by RT-PCR for the presence of Arabis mosaic virus (ArMV), Cherry leaf roll virus (CLRV), Strawberry latent ringspot virus (SLRV), Olive latent virus 1 (OLV-1) and Olive leaf yellowing-associated virus (OLYaV), using virus-specific primers reported in the literature. About one third (31%) of the trees were infected. In particular, the closterovirus OLYaV was the most widespread, as it was detected in 23.7% of the samples, followed by the necrovirus OLV-1 (8.3%), the two nepoviruses CLRV (2%) and ArMV (0.3%), and the sadwavirus SLRV (0.3%). A high variability was detected in the HSP70 gene of Lebanese and Italian OLYaV isolates, for at least nine different patterns were obtained when this genomic region was subjected to single-strand conformation polymorphism (SSCP) analysis.
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- 2005
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25. Isolation and partial characterization of a novel cytorhabdovirus from citrus trees showing foliar symptoms in Iran
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Mohammad Sadegh Sadeghi, Maria Saponari, Giuliana Loconsole, Alireza Afsharifar, Giovanni P. Martelli, Keramatollah Izadpanah, and Angelo De Stradis
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0301 basic medicine ,Citrus psorosis virus ,Cytorhabdovirus ,food.ingredient ,viruses ,food and beverages ,Plant Science ,Biology ,Herbaceous plant ,biology.organism_classification ,Virology ,Virus ,Nucleoprotein ,03 medical and health sciences ,chemistry.chemical_compound ,030104 developmental biology ,food ,chemistry ,RNA polymerase ,Plant virus ,Agronomy and Crop Science ,Gene - Abstract
Citrus ringspot is a graft-transmissible disease, and at least two taxonomically distinct viral species are associated with this syndrome: Citrus psorosis virus (CPsV) and Indian citrus ringspot virus (ICRSV). Neither of these two viruses was detected, however, by serological or molecular assays in symptomatic tissues from citrus trees in southern Iran, where the ringspot syndrome is widespread. By contrast, electron microscopy and molecular assays revealed the presence of a rhabdovirus-like virus, which was graft transmitted to several citrus species and mechanically to herbaceous hosts. Virus particles were bacilliform and resembled rhabdovirus nucleocapsids deprived of the lipoprotein envelope. Partial sequences of the viral nucleoprotein and RNA polymerase genes showed a distant genetic relatedness with cytorhabdoviruses. This virus appears to be a novel species, for which the name Iranian citrus ringspot-associated virus (IrCRSaV) is suggested.
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- 2015
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26. Molecular detection of olive viruses
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Vito Nicola Savino, Francesco Grieco, Maria Saponari, Raed Alkowni, and G. P. Martelli
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RNA silencing ,Inoculation ,law ,Plant virus ,Plant Science ,Horticulture ,Biology ,Agronomy and Crop Science ,Virology ,Virus ,Polymerase chain reaction ,law.invention ,Microbiology - Abstract
Olive hosts 13 viruses belonging in seven different genera. Additional non-mechanically transmissible viruses probably infect olive in nature, as suggested by the widespread occurrence of double-stranded RNAs (dsRNAs) in trees from which no viruses can be recovered by manual inoculation. Because sanitary selection appears to be the only measure for restraining virus dissemination through propagating material, detection methods are needed which are more sensitive and reliable than those currently available (biological and serological). The following molecular techniques have therefore been used and their efficiency compared: (1) dsRNA analysis; (2) dot-blot hybridization with digoxigenin-labelled riboprobes in separate reactions or in mixture; and (3) reverse transcription-polymerase chain reaction (RT-PCR). It was found that: (1) dsRNAs were detected in 210 out of 286 olive accessions (73.4%) coming from six different Italian regions; (2) one-step RT-PCR yielded much better results using TNA extracts than crude sap; and (3) dot-blot hybridization of denatured dsRNAs with digoxigenin-labelled virus-specific riboprobes was the most reliable detection method available.
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- 2000
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27. Identification and characterization of citrus yellow vein clearing virus, a putative new member of the genus Mandarivirus
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Annalisa Giampetruzzi, Raymond Yokomi, Vito Nicola Savino, Serdar Satar, O. Potere, Maria Saponari, Giuliana Loconsole, Nuket Onelge, Orhan Bozan, A. De Stradis, and Çukurova Üniversitesi
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Gene Expression Regulation, Viral ,Citrus ,CYVCV ,food.ingredient ,MANDARIVIRUS ,Alphaflexiviridae ,Nucleic acid sequence ,food and beverages ,Plant Science ,Genome, Viral ,Biology ,biology.organism_classification ,Virology ,Genome ,Virus ,DNA sequencing ,food ,Plant virus ,Mandarivirus ,Flexiviridae ,Agronomy and Crop Science ,Phylogeny ,Genomic organization ,Plant Diseases - Abstract
PubMedID: 22913410 Molecular features and genomic organization were determined for Citrus yellow vein clearing virus (CYVCV), the putative viral causal agent of yellow vein clearing disease of lemon trees, reported in Pakistan, India, and more recently in Turkey and China. CYVCV isolate Y1 from Adana, Turkey, was used for deep sequencing analysis of the virusinduced small RNA fractions and for mechanical and graft inoculation of herbaceous and citrus indicator plants. A polyclonal antiserum was developed from CYVCV-Y1 purified from Phaseolus vulgaris and used in western blot assays to characterize the coat protein of CYVCV-Y1 and determine its serological relationship with related viruses. Contigs assembled from the Illumina sequenced short reads were used to construct the whole genome of Citrus yellow vein clearing virus (CYVCV), consisting in a positive-sense RNA of 7,529 nucleotides and containing six predicted open reading frames. The CYVCV genome organization and size resembled that of flexiviruses, and search for sequence homologies revealed that Indian citrus ringspot virus (ICRSV) (Mandarivirus, Alphaflexiviridae) is the most closely related virus. However, CYVCV had an overall nucleotide sequence identity of ?74% with ICRSV. Although the two viruses were similar with regard to genome organization, viral particles, and herbaceous host range, CYVCV caused different symptoms in citrus and was serologically distinct from ICRSV. Primer pairs were designed and used to detect the virus by conventional and quantitative reverse transcription-polymerase chain reaction on yellow vein clearing symptomatic field trees as well as graft- and mechanically inoculated host plants. Collectively, these data suggest that CYVCV is the causal agent of yellow vein clearing disease and represents a new species in the genus Mandarivirus. © 2012 The American Phytopathological Society.
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- 2012
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28. Spittlebugs as vectors of Xylella fastidiosa in olive orchards in Italy
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Daniele Cornara, Maria Saponari, Giuliana Loconsole, Angelo De Stradis, Domenico Bosco, Francesco Porcelli, Giovanni P. Martelli, Rodrigo P. P. Almeida, Adam R. Zeilinger, and Donato Boscia
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0106 biological sciences ,Canopy ,Philaenus spumarius ,Acacia ,Biology ,Auchenorryncha ,01 natural sciences ,Emerging diseases Plant pathogenic bacteria Auchenorryncha Aphrophorida ,Aphrophoridae ,Botany ,Emerging diseases, Plant pathogenic bacteria, Auchenorryncha, Aphrophoridae ,Nymph ,Emerging diseases ,Plant pathogenic bacteria ,Forestry ,biology.organism_classification ,Polygala ,Olive trees ,010602 entomology ,Xylella fastidiosa ,Entomology ,Zoology ,Agronomy and Crop Science ,010606 plant biology & botany - Abstract
© 2016, The Author(s). The recent introduction of Xylella fastidiosa in Europe and its involvement in the Olive Quick Decline Syndrome (OQDS) in Apulia (Salento, Lecce district, South Italy) led us to investigate the biology and transmission ability of the meadow spittlebug, Philaenus spumarius, which was recently demonstrated to transmit X. fastidiosa to periwinkle plants. Four xylem-sap-feeding insect species were found within and bordering olive orchards across Salento during a survey carried out from October 2013 to December 2014: P. spumarius was the most abundant species on non-olive vegetation in olive orchards as well as on olive foliage and was the only species that consistently tested positive for the presence of X. fastidiosa using real-time PCR. P. spumarius, whose nymphs develop within spittle on weeds during the spring, are likely to move from weeds beneath olive trees to olive canopy during the dry period (May to October 2014). The first X. fastidiosa-infective P. spumarius were collected in May from olive canopy: all the individuals previously collected on weeds tested negative for the bacterium. Experiments demonstrated that P. spumarius transmitted X. fastidiosa from infected to uninfected olive plants. Moreover, P. spumarius acquired X. fastidiosa from several host plant species in the field, with the highest acquisition rate from olive, polygala and acacia. Scanning electron microscopy (SEM) revealed bacterial cells resembling X. fastidiosa in the foreguts of adult P. spumarius. The data presented here are essential to plan an effective IPM strategy and limit further spread of the fastidious bacterium.
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29. Xylella fastidiosa in Olive in Apulia: Where We Stand
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Donato Boscia, Annalisa Giampetruzzi, Giuliana Loconsole, Maria Saponari, and Pasquale Saldarelli
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0106 biological sciences ,0301 basic medicine ,Genotype ,Plant Science ,Xylella ,01 natural sciences ,law.invention ,03 medical and health sciences ,law ,Olea ,Quarantine ,media_common.cataloged_instance ,European union ,media_common ,Plant Diseases ,biology ,Outbreak ,biology.organism_classification ,Pathogenicity ,3. Good health ,Horticulture ,030104 developmental biology ,Italy ,13. Climate action ,Xylella fastidiosa ,olive ,outbreak ,Agronomy and Crop Science ,010606 plant biology & botany - Abstract
A dramatic outbreak of Xylella fastidiosa decimating olive was discovered in 2013 in Apulia, Southern Italy. This pathogen is a quarantine bacterium in the European Union (EU) and created unprecedented turmoil for the local economy and posed critical challenges for its management. With the new emerging threat to susceptible crops in the EU, efforts were devoted to gain basic knowledge on the pathogen biology, host, and environmental interactions (e.g., bacterial strain(s) and pathogenicity, hosts, vector(s), and fundamental drivers of its epidemics) in order to find means to control or mitigate the impacts of the infections. Field surveys, greenhouse tests, and laboratory analyses proved that a single bacterial introduction occurred in the area, with a single genotype, belonging to the subspecies pauca, associated with the epidemic. Infections caused by isolates of this genotype turned to be extremely aggressive on the local olive cultivars, causing a new disease termed olive quick decline syndrome. Due to the initial extension of the foci and the rapid spread of the infections, eradication measures (i.e., pathogen elimination from the area) were soon replaced by containment measures including intense border surveys of the contaminated area, removal of infected trees, and mandatory vector control. However, implementation of containment measures encountered serious difficulties, including public reluctance to accept control measures, poor stakeholder cooperation, misinformation from some media outlets, and lack of robust responses by some governmental authorities. This scenario delayed and limited containment efforts and allowed the bacterium to continue its rapid dissemination over more areas in the region, as shown by the continuous expansion of the official borders of the infected area. At the research level, the European Commission and regional authorities are now supporting several programs aimed to find effective methods to mitigate and contain the impact of X. fastidiosa on olives, the predominant host affected in this epidemic. Preliminary evidence of the presence of resistance in some olive cultivars represents a promising approach currently under investigation for long-term management strategies. The present review describes the current status of the epidemic and major research achievements since 2013.
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30. Feeding behavior in relation to spittlebug transmission of Xylella fastidiosa
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Daniele Cornara, Elisa Garzo, Monica Marra, Alberto Fereres, Maria Saponari, Aranzazu Moreno, and Marina Morente
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0106 biological sciences ,media_common.quotation_subject ,Philaenus spumarius ,Zoology ,Insect ,010603 evolutionary biology ,01 natural sciences ,Electrical penetration graph ,Fastidious bacterium ,Ingestion ,media_common ,biology ,Inoculation ,fungi ,Xylem ,food and beverages ,Olive ,Foregut ,Transmission dynamic ,biology.organism_classification ,010602 entomology ,EPG ,Oleander ,Xylella fastidiosa ,Agronomy and Crop Science - Abstract
Here, we provide the first insights into the transmission dynamics of the bacterium Xylella fastidiosa by the meadow spittlebug Philaenus spumarius, gathered through DC EPG (electrical penetration graph)-assisted transmission tests and comparative observations of the probing and feeding behavior of infective versus non-infective vectors on healthy olive plants. Bacterial cells binding to P. spumarius’ foregut occurred at a very low rate and in a time as short as 15 min spent by the insect in xylem ingestion or activities interspersed with xylem ingestion (interruption during xylem ingestion and resting). P. spumarius inoculation of bacterial cells into the xylem was exclusively associated with an early (ca. 2 to 7 min after the onset of the first probe) and occasional behavior, provisionally termed waveform Xe, presumably related to egestion regulated by pre-cibarial valve fluttering. Infective spittlebugs compared to non-infective ones exhibited: (i) longer non-probing and shorter xylem ingestion; (ii) longer duration of single non-probing events; (iii) fewer sustained ingestions (ingestion longer than 10 min) and interruptions of xylem activity (N); and (iv) longer time required to perform the first probe. These observations suggest difficulties in feeding of infective P. spumarius probably caused by the presence of X. fastidiosa within the foregut. Overall, our data indicate that likely short time—few minutes—is required for X. fastidiosa transmission by P. spumarius; thus, vector control strategies should aim at preventing spittlebug access to the host plant. Furthermore, our findings represent an important contribution for further research on the disruption of spittlebug–bacterium interactions.
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