Following the introduction and establishment of the plant pathogenic bacterium Xylella fastidiosa (Xf) in the Apulia Region (southern Italy), olive turned to be the main host of the Salentinian bacterial strain and the majorly devastated crop. The mechanism of pathogenicity of Xf is still not completely understood and no means to cure the bacterium in the infected plants are available yet. Nevertheless, the alteration of microbial communities and effects in the expression of symptoms of Xf-infected plants is poorly studied. We are investigating the microbiome of Xf-infected olives by a shotgun metagenomic DNA sequencing approach that avoids the limitations of amplicon sequencing. Data obtained (28,333,924 and 29,096,610 reads from Xf-infected and healthy plants) were analyzed by MetaPhlAn, a metagenomic abundance estimation tool which maps reads to a set of selected marker sequences. Libraries from xylem tissues revealed a complex community in which small symbiotic bacteria of insects, i.e. Candidatus Zinderia insecticola and Candidatus Carsonella ruddii represented the 31% and 22% of the total population. Xf reaches in infected plants the 12% of the total microbial community. Studies are ongoing to characterize the microbial communities in the xylem sap of tolerant and susceptible olive cultivars, to envisage a control strategy based on the manipulation of these resident communities and to identify endosymbiont(s) which may be used to reduce the severity of symptoms. To this end, the evaluation of an endosymbiont bacterium for its potential to colonize Xf-infected olive tissues is underway.

We report here the complete and annotated genome sequence of the plant-pathogenic bacterium Xylella fastidiosa subsp. pauca strain De Donno. This strain was recovered from an olive tree severely affected by olive quick decline syndrome (OQDS), a devastating olive disease associated with X. fastidiosa infections in susceptible olive cultivars.

A primary therapeutic goal in Alzheimer’s disease (AD) is to reduce the quantity of amyloid b protein (A b) present in the brain. To develop an effective, safe system for vaccination against Alzheimer’s disease, the plant virus Cucumber mosaic virus (CMV) was engineered genetically to express A b -derived fragments that stimulate mainly humoral immune responses. Six chimeric constructs, bearing the A b 1–15 or the A b 4–15 sequence in positions 248, 392 or 529 of the CMV coat protein (CP) gene, were created. Viral products proved to be able to replicate in their natural host. However, only chimeric A b 1–15-CMVs were detected by A b 1–42 antiserum in Western blot analysis. Experimental evidence of Immunoelectron microscopy revealed a complete decoration of A b 1–15-CMV248 and A b 1–5-CMV392 following incubation with either anti-A b 1–15 or anti-A b 1–42 polyclonal antibodies. These two chimeric CMVs appear to be endowed with features making them possible candidates for vaccination against Alzheimer’s disease.

Two dsRNA molecules with an estimated lenght of 1.5 Kbp were identified and characterized from leaves of a Japanese persimmon (Diospyros kaki) tree, showing veinlets necrosis on both sides of leaf blades.DOP-PCR recognized two genomic fragments of a bipartite cryptic virus, for which the name of Persimmon cryptic virus (PeCV) is proposed. RLM-RACE leaded to the sequencing of a 1,510 bp contig identified as dsRNA-1 and a 1,491 bp complete segment identified as dsRNA-2. The two genomic fragments resulted both monocistronic and harbored conserved domains related to RNA-dependent RNA polymerase (RdRP) and capsid protein (CP) of species associated to Alphacryptovirus genus. Phylogenetic analysis of RdRP sequence showed highest amino acid identity with Black raspberry cryptic virus (BrCV, 63 %), Pepper cryptic virus 2 (PCV-2, 52 %) and -1 (PCV-1, 46 %). Whereas the CP putatively encoded by dsRNA-2 shared highest identity with Mulberry cryptic virus 1 (MCV-1, 49 %), PCV-2 (39 %) and PCV-1 (32 %). N-J phylogenetic analysis confirmed those relationships and delivered PeCV in a cluster with phyto-cryptoviruses belonging to genera Alpha- and Betacryptovirus, quite far distinguished from myco-cryptoviruses, gathered in genus Partitivirus.Virus-specific primers for RT-PCR were successfully designed inside the CP region to detect PeCV in several symptomless trees found in different orchards of Apulia (Southern Italy), thus proving that infection may be fairly common and presumably latent.Policlonal antiserum (kindly provided by Dr. M. Turina, CNR-IVV, Torino, Italy) specific to the CP of family-related Beet cryptic virus 2 (BCV-2) was profitably used for western blot detection of a 45-50 KDa band, coherent with predicted size of dsRNA-2 product. Furthermore, antibodies were useful for ISEM observation and subsequent decoration of PeCV particles, proved to be isometric, around 30 nm in diameter, with rounded shape lacking in fine structural details, not easily permeable by negative stain.

Xylella fastidiosa has recently been identified in the Apulian province of Lecce (south-eastern Italy) in olive trees affected by a devastating disease denoted Olive quick decline syndrome (OQDS), that appeared suddenly in 2010. Symptoms of OQDS consist of withering and desiccation of scattered terminal shoots, which rapidly expands to the rest of the canopy, and results in the collapse and death of the tree. The identification of X. fastidiosa in OQDS-affected trees represents the first confirmed detection of this bacterium in the European Union (EU), but its exact role in the aetiology of this disease is yet to be determined Since X. fastidiosa is a regulated quarantine pathogen in the EU, upon request of the Apulian Plant Protection Service, surveys were initiated in order to delineate the contaminated area. To this effect, diagnostic protocols based on ELISA and conventional PCR for X. fastidiosa detection in olive samples were compared and validated via an interlaboratory ring-test in which three accredited laboratories, all located in Italy, participated. Both procedures proved to be equally effective but, due to the simplicity of sample preparation, ELISA was chosen for the large-scale X. fastidiosa monitoring programme now in progress.

The recent Xylella fastidiosa subsp. pauca (Xfp) outbreak in olive (Olea europaea) groves in southern Italy is causing a destructive disease denoted Olive Quick Decline Syndrome (OQDS). Field observations disclosed that Xfp-infected plants of cv. Leccino show milder symptoms, than the more widely grown and highly susceptible cv. Ogliarola salentina. To ascertain whether these field observations underlie a tolerant condition of cv. Leccino, which could be exploited for lessening the economic impact of the disease on the local olive industry, transcriptional changes occurring in plants of the two cultivars affected by Xfp were investigated. A global transcriptome profiling comparing susceptible (Ogliarola salentina) and tolerant (Leccino) olive cultivars, infected or not by Xfp, was done on messenger RNA (mRNAs) extracted from xylem tissues. The study revealed that 659 and 447 genes were differentially regulated in cvs Leccino and Ogliarola upon Xfp infection, respectively, whereas 512 genes were altered when the transcriptome of both infected cultivars was compared. Analysis of these differentially expressed genes (DEGs) shows that the presence of Xfp is perceived by the plants of both cultivars, in which it triggers a differential response strongly involving the cell wall. Up-regulation of genes encoding receptor-like kinases (RLK) and receptor-like proteins (RLP) is the predominant response of cv. Leccino, which is missing in cv. Ogliarola salentina. Moreover, both cultivars react with a strong re-modelling of cell wall proteins. These data suggest that Xfp elicits a different transcriptome response in the two cultivars, which determines a lower pathogen concentration in cv. Leccino and indicates that this cultivar may harbor genetic constituents and/or regulatory elements which counteract Xfp infection. These findings suggest that cv. Leccino is endowed with an intrinsic tolerance to Xfp, which makes it eligible for further studies aiming at investigating molecular basis and pathways modulating its different defense response.

The draft genome sequence of Xylella fastidiosa CO33 isolate, retrieved from symptomatic leaves of coffee plant intercepted in northern Italy, is reported. The CO33 genome size is 2,681,926 bp with a GC content of 51.7%. Isolate CO33, cultured from a coffee plant intercepted in northern Italy, represents a novel multilocus sequence typing profile, ST72 (G. Loconsole, personal communication). Isolates genetically related to CO33 were found in several coffee plants imported in October 2014 from Costa Rica through the Netherlands (European Food Safety Authority [EFSA] 2015).

We determined the draft genome sequence of the Xylella fastidiosa CoDiRO strain, which has been isolated from olive plants in southern Italy (Apulia). It is associated with olive quick decline syndrome (OQDS) and characterized by extensive scorching and desiccation of leaves and twigs.

The recent findings of the plant pathogenic bacterium Xylella fastidiosa (Xf), infecting several plant species in Italy and France, raised major concerns for its potential impact on the EU and Mediterranean agriculture. In the current EU outbreaks, olive is the predominantly affected crop, in which the bacterium has been consistently associated with a new severe syndrome, denoted Olive Quick Decline". So far, no effective treatments are available to cure infected plants. However, several approaches have been explored, mainly in grapevine and citrus, to reduce bacterial movement and multiplication or directly targeting Xf-cells for lysis.Current knowledge shows that the virulence of the pathogen relies on a fine balance between more motile bacterial forms, able to move and proliferate within xylem vessels, and sticky cells forming a biofilm, which are responsible for vessels blockage and insect acquisition. This different behavior is regulated in a cell density-dependent manner by a diffusible signaling factor (DSF), produced by rpfF-gene, that initiates a transduction cascade resulting in up- or down-regulation of several genes.The aim of our investigation is to explore "pathogen confusion" strategy, by altering DSF level in planta, for reducing the impact of Xf-infections in olives. To this end, a plant viral-based vector, harboring the rpfF-gene, has been engineered to induce transient DSF production. Experiments will verify if, upon DSF accumulation, the bacterium will be less motile and more adhesive to the surface of xylem vessels, thus showing a decreased virulence in infected plants.

The Italian olive germplasm comprises one of, if not the highest number of authoctonous cultivars in the world. The recent finding of severe infections of Xylella fastidiosa in Olea europaea, a relatively new host for this harmful pathogen, prompted a survey for a preliminary evaluation of the susceptibility of different of its cultivars

The Italian olive germplasm comprises one of, if not the highest number of authoctonous cultivars in the world. The recent finding of severe infections of Xylella fastidiosa in Olea europaea, a relatively new host for this harmful pathogen, prompted a survey for a preliminary evaluation of the susceptibility of different of its cultivars

A severe olive decline of unknown aetiology is currently under investigation in Apulia, (southern Italy). The decline affects mainly aged trees (100 years or older) growing in the Gallipoli bay, on an area extending about 10.000 ha located on the western coast of the Salento peninsula. The disease is characterized by a rapid dieback of shoots, twigs and branches followed by death of the entire tree. Leaf tips and margins turn dark yellow to brown, a condition that spreads inward, eventually leading to desiccation. Symptoms progress in severity from older to younger leaves. Desiccated leaves and mummified drupes remain attached to the shoots. Trunks, branches and twigs viewed in cross section show more or less extensive discolorations of the vascular elements, as reported earlier by Carlucci et al. (2008), plus sapwood and vascular cambium. Numerous galleries of the leopard moth, Zeuzera pyrina and bark beetles occurr on the trunks, branches and twigs of affected plants. Isolations from discolored sapwood made on different growing media allowed the recovery of a number of fungi, Phaeoacremonium spp. in particular, which were identified based on morphometric characters and sequencing of ITS and ?-tubulin gene regions (Mostert et al., 2006). P. parasiticum was the most frequent species, followed by P. rubrigenun, P. aleophilum, P. alvesi,. Fungi belonging to the genus Phaemoniella were also found. This is the first report of P. parasiticum and P. alvesii on olive in Italy. The role of these fungal species, alone or in combination with other plant pathogens, in determining the symptoms observed on olive trees is currently under investigation.

Xylella fastidiosa is a plant-pathogenic bacterium recently introduced in Europe that is causing decline in olive trees in the South of Italy. Genetic studies have consistently shown that the bacterial genotype recovered from infected olive trees belongs to the sequence type ST53 within subspecies pauca. This genotype, ST53, has also been reported to occur in Costa Rica. The ancestry of ST53 was recently clarified, showing it contains alleles that are monophyletic with those of subsp. pauca in South America. To more robustly determine the phylogenetic placement of ST53 within X. fastidiosa, we performed a comparative analysis based on single nucleotide polymorphisms (SNPs) and the study of the pan-genome of the 27 currently public available whole genome sequences of X. fastidiosa. The resulting maximum-parsimony and maximum likelihood trees constructed using the SNPs and the pan-genome analysis are consistent with previously described X. fastidiosa taxonomy, distinguishing the subsp. fastidiosa, multiplex, pauca, sandyi, and morus. Within the subsp. pauca, the Italian and three Costa Rican isolates, all belonging to ST53, formed a compact phylotype in a clade divergent from the South American pauca isolates, also distinct from the recently described coffee isolate CFBP8072 imported into Europe from Ecuador. These findings were also supported by the gene characterization of a conjugative plasmid shared by all the four ST53 isolates. Furthermore, isolates of the ST53 clade possess an exclusive locus encoding a putative ATP-binding protein belonging to the family of histidine kinase-like ATPase gene, which is not present in isolates from the subspecies multiplex, sandyi, and pauca, but was detected in ST21 isolates of the subspecies fastidiosa from Costa Rica. The clustering and distinctiveness of the ST53 isolates supports the hypothesis of their common origin, and the limited genetic diversity among these isolates suggests this is an emerging clade within subsp. pauca.

In 2013, an outbreak of Xylella fastidiosa was first identified in Apulia (southeastern Italy) in olive trees severely affected by a novel disease denoted Olive Quick Decline Syndrome (Complesso del Disseccamento Rapido dell'Olivo, CoDiRO in Italian). CoDiRO was first widely observed in 2010 and is characterized by extensive scorching and desiccation of leaves and twigs. At a preliminary examination, many of such trees appeared to be impacted by the presence of three different agents: (i) the leopard moth (Zeuzera pyrina), which drills galleries in the branches and trunks of olives; (ii) a set of xylem-inhabiting fungi of different genera (Phaeoacremonium and Phemoniella, in particular) (Nigro et al. 2014), which invade the sapwood taking also advantage of the moth galleries; and (iii) the bacterium X. fastidiosa. As time passed and a better insight into the disease was gained with field and laboratory observations, it became evident that the role of the leopard moth is minor, whereas the fungi could play the role of aggravators. Although the etiological role of X. fastidiosa is yet to be determined, the finding of this quarantine bacterium in the European Union prompted urgent investigations to address the many open questions and to enforce actions for its containment to avoid further spread in the neighboring areas and in other countries.

Xylella fastidiosa is an important pathogen of commercial crops, landscape trees and ornamentals in North and South America. In Europe, symptoms resembling those caused by X. fastidiosa have occasionally been observed, but the presence of this EPPO quarantinable pathogen has never been confirmed. Recently, a rapidly spreading decline of aged olive trees has taken place in a large area of the Salento peninsula (Apulia, southern Italy). PCR assays on extracts from leaf veins and petioles of diseased trees gave positive reactions using X. fastidiosa gene-specific primers. In particular, PCR amplicons were generated by primers targeting the conserved hypothetical HL protein (Francis et al., 2006), the RNA polymerase sigma-70 factor, and the 16S rDNA genes (Rodrigues et al., 2003). Furthermore, molecular tests extended to almond and oleander trees with leaf scorching symptoms, growing next to diseased olive orchards, were also positive for X. fastidiosa. PCR products amplified from diseased olive trees were sequenced in duplicate and the sequences (EMBL-EBI provisional accession Nos HX2000034932- HX2000035003) showed 95 to 99% identity with the homologous genomic regions of X. fastidiosa. Tests for ascertaining the presence of X. fastidiosa by DAS-ELISA using two commercial kits (Agadia, USA and Bio-Rad, USA) were also positive, thus confirming molecular tests. Studies aimed at isolating the bacterium, determining the strain, evaluating its pathogenicity, and identifying the putative local vector(s) are currently in progress. X. fastidiosa has an extensive natural host range, including olive, from which the bacterial genotype A, pathogenic to oleander and almond, but not to grapevine, has been isolated in California (Krugner et al., 2010).

The Cucumber mosaic virus (CMV) is an isodiametric plant virus with an extremely wide host range, present worldwide. CMV chimeric particles (R9-CMV), engineered to express a 27-aa synthetic peptide derived from Hepatitis C virus (HCV), were demonstrated to be stable under simulated gastric and intestinal conditions. Then the possibility of inducing a humoral immune response in rabbits fed with R9-CMV infected lettuce plants was demonstrated, suggesting that this system could function as a confirming tool of a bioreactor for the production of a stable edible vaccine against HCV.

Condotta in 11 diversi comuni della provincia di lecce, l'indagine era finalizzata a verificare l'incidenza di xylella fastidiosa negli olivi con manifestazione conclamata di disseccamento rapido (oqds), ovvero con chioma compromessa per oltre il 70%. I risultati hanno evidenziato la strettissima associazione tra il batterio e la malattia, a testimonianza dell'elevata sensibilità dei metodi diagnostici pcr ed elisa in particolar modo nei focolai maturi (da almeno due anni).

Discovery of Xylella fastidiosa from olive trees with "Olive quick decline syndrome" in October 2013 on the west coast of the Salento Peninsula prompted an immediate search for insect vectors of the bacterium. The dominant xylem-fluid feeding hemipteran collected in olive orchards during a 3-mo survey was the meadow spittlebug, Philaenus spumarius (L.) (Hemiptera: Aphrophoridae). Adult P. spumarius, collected in November 2013 from ground vegetation in X. fastidiosa-infected olive orchards, were 67% (40 out of 60) positive for X. fastidiosa by polymerase chain reaction (PCR) assays. Euscelis lineolatus Brullé were also collected but tested negative for the pathogen. Transmission tests with P. spumarius collected from the Salento area were, therefore, conducted. After a 96-h inoculation access period with 8 to 10 insects per plant and a 30-d incubation period, PCR results showed P. spumarius transmitted X. fastidiosa to two of five periwinkle plants but not to the seven olive plants. Sequences of PCR products from infected periwinkle were identical with those from X. fastidiosa-infected field trees. These data showed P. spumarius as a vector of X. fastidiosa strain infecting olives trees in the Salento Peninsula, Italy. © 2014 Entomological Society of America.

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.

Accurate detection of harmful plant pathogens that cause severe crop losses is critical for the successful control and management of emerging diseases. Following the recent outbreak of Xylella fastidiosa in the Apulia region (southern Italy), diagnostic protocols based on ELISA and conventional PCR were successfully used and adopted for large-scale surveys. However, a validation of these protocols for pathogen detection by different laboratories in diverse susceptible hosts is periodically needed to guarantee optimum sensitivity and reliability

The isolation in pure culture of the Xylella fastidiosa strain associated with the quick decline syndrome of olive, recently observed in Apulia (Salento peninsula, southern Italy) was attempted from symptomatic, naturally infected olive and oleander plants, and a periwinkle seedling that had been exposed to, and was infected by Xylella-positive spittlebugs. Prior to isolation, the presence of Xylella was ascertained in all donor hosts by PCR, indirect immunofluorescence and electron microscopy. Isolations from olive failed because of the heavy contamination by bacteria other than Xylella. By contrast, pure bacterial cultures were obtained from oleander and periwinkle extracts plated in periwinkle wilt gelrite (PWG) and buffered cysteine-yeast extract (BCYE) media. In both media, colonies were slow-growing, small-sized (less than 1 mm 25 days from plating), non pigmented, opalescent and exhibited the same morphology, except for the margin that was entire in BCYE and somewhat irregular in PWG. Bacterial cells were rod-shaped with rounded ends, had a thick and rippled cell wall, an average width of 0.35 mu m, and a maximum length of ca. 5 mu m. They gave a positive reaction in immunofluorence assays and were clearly decorated by colloidal gold in immunogold labelling tests. Sequenced PCR products amplified from periwinkle and oleander colonies shared 97-99% sequence identity with known X. fastidiosa strains from database and were 100% identical to one another and to comparable sequences obtained from infected olive trees. These sequences grouped in a distinct cluster of a branch comprising X. fastidiosa isolates belonging to the subspecies pauca.

The Olive quick decline syndrome (OQDS) represents the first outbreak of Xylella fastidiosa (Xf) in Europe. Disease symptoms include extensive leaf scorching and branch dieback, discolouration of the vascular system and a generalized progressive decline that leads the plants to death. To determine the role of Xf in the OQDS aetiology, pure cultures of the local bacterial strain (CoDiRO) were obtained and used in greenhouse pathogenicity tests. Axenic cultures were readily established from oleander and periwinkle, whereas initial attempts to isolate Xf from infected olives failed due to the heavy contamination by bacteria other than Xf.

Taxonomically, Xylella fastidiosa (Xf) constitutes a single species with four recognized subspecies (Xf. fastidiosa, multiplex, pauca and sandyi). For identifying subspecies and determining the taxonomic allocation of novel bacterial isolates, a widely used approach is multilocus sequence typing (MLST) analysis that encompasses seven different loci. This approach was used for the identifcation of the Xf strain isolated from olive trees affected by the quick decline syndrome (OQDS) in the the Salento peninsula (Apulia, south-eastern Italy).

In the course of surveys carried out in June 2014 in the Salento (Apulia, southern Italy) area affected by an epidemic of a strain of Xylella fastidiosa subsp. pauca (Cariddi et al., 2014) denoted CoDiRO (abbreviation from the Italian name "Complesso del Disseccamento Rapido dell'Olivo"), the following symptomatic plants were observed: (i) cherry (Prunus avium), 13 trees showing scanty vegetation and bud failure, but no leaf scorching; (ii) myrtle-leaf milkwort (Polygala myrtifolia), three shrubs showing extensive desiccation of twigs and scorched leaves; (iii) coastal rosemary (Westringia fruticosa), one shrub with extensive chlorosis and desiccation of the leaves. Samples collected from all these hosts (except for two of the 13 cherry plants) were ELISA- and PCR-positive upon testing with the protocols described by Loconsole et al. (2014). Sequencing of the amplified products from five housekeeping genes (gyrB, 16S rRNA, dnaK, tonB, RNA polymerase sigma factor) and of the PCR products obtained using the X. fastidiosa strain-specific primers 272-1int/272- 2int, showed that all these amplicons, regardless of the host of origin, had 100% sequence identity with the homologous products amplified from diseased olive trees (Cariddi et al., 2014). These results provide evidence that all the analyzed positive samples contain the same X. fastidiosa strain infecting olives in the same area. With the exception of cherry, for which there is a recorded infection by X. fastidiosa subsp. fastidiosa in California (Hernandez-Martinez et al., 2007), to the best of our knowledge P. myrtifolia and W. fruticosa are hitherto unreported hosts of this bacterium.

A strain of Xylella fastidiosa subsp. pauca denoted CoDiRO (abbreviation from the Italian name "Complesso del Disseccamento Rapido dell'Olivo") is associated with a novel severe disease denoted "Olive Quick Decline Syndrome" (OQDS), which appeared suddenly in 2010 in Apulia (south-eastern Italy).

To investigate the role of herbaceous plants as hosts of Xylella fastidiosa, monthly sampling of the native flora of two heavily infected olive groves and of the sides of the adjacent dirt roads was conducted from January 2014 onwards. One of the orchards had not been subjected to weeding, whereas periodic tillage had been carried out in the other. Overall, more than 100 species of 40 monocotyledonous and dicotyledonous families were collected.

To investigate the role of herbaceous plants as hosts of Xylella fastidiosa, monthly sampling of the native flora of two heavily infected olive groves and of the side of the adjacent dirt roads was conductedfrom January 2014 onwards. One of the orchards had not been subjected to weeding, whereas periodic tillage had been carried out in the other. Overall, more than 100 species of 40 monocotyledonous anddicotyledonous families were collected, photographed and identified, their phenological stage was recorded using the Keller-Baggiolini scale, their period of presence and the type of distribution prevailing in the field (e.g. whether the species scattered or concentrated under olive trees or along the edges of the dry stone walls) was assessed, as well as the abundance-dominance indices according to the Braun-Blanquet method. At all sites monitored, Philenus spumarius, the main and most important vector of Xylella fastidiosa so far found in the area of the outbreak, was present with abundant populations on herbaceous species in the spring and on olive trees from the middle of May throughout the summer. All weed samples collected, in pools of 4-5 plants, were tested by DAS-ELISA and the uncertain results were verified by PCR. So far, none of the samples analyzed, in excess of 600, proved to host Xylella fastidiosa, confirming the preliminary observations that, by and large, weeds may not have a major role in the epidemiology of X. fastidiosa in the considered area. However, since sampling of the summer/autumn flora is yet to be done, a better insight into the epidemiological role of these plants will become available in the coming months, in conjunction with the migration of the vectors from the olive trees onto the native flora with the consequent possible inoculation of the bacterium.

Plant pathogens cause significant losses to agricultural yields and increasingly threaten food security, ecosystem integrity and societies in general. Xylella fastidiosa is one of the most dangerous plant bacteria worldwide, causing several diseases with profound impacts on agriculture and the environment. Primarily occurring in the Americas, its recent discovery in Asia and Europe demonstrates that X. fastidiosa's geographic range has broadened considerably, positioning it as a reemerging global threat that has caused socioeconomic and cultural damage. X. fastidiosa can infect more than 350 plant species worldwide, and early detection is critical for its eradication. In this article, we show that changes in plant functional traits retrieved from airborne imaging spectroscopy and thermography can reveal X. fastidiosa infection in olive trees before symptoms are visible. We obtained accuracies of disease detection, confirmed by quantitative polymerase chain reaction, exceeding 80% when high-resolution fluorescence quantified by three-dimensional simulations and thermal stress indicators were coupled with photosynthetic traits sensitive to rapid pigment dynamics and degradation. Moreover, we found that the visually asymptomatic trees originally scored as affected by spectral plant-trait alterations, developed X. fastidiosa symptoms at almost double the rate of the asymptomatic trees classified as not affected by remote sensing. We demonstrate that spectral plant-trait alterations caused by X. fastidiosa infection are detectable previsually at the landscape scale, a critical requirement to help eradicate some of the most devastating plant diseases worldwide.

Gli istituti di ricerca pugliesi riportano i risultati ottenuti dall'impiego di attivatori delle difese della pianta e dell'N-acetilcisteina per il contenimentodei sintomi del complesso del disseccamento rapido dell'olivo.

Osservazioni e rilievi di campo integrati da saggi diagnostici effettuati su diverse cultivar in un'area fortemente infetta da Xylella fastidiosa confermano i fenomeni di resistenza già osservati in precedenti studi sulla cultivar Leccino e individuano nella selezione FS-17® un'ulteriore e potenziale fonte di resistenza al batterio. Al contrario, si rafforzano le evidenze sull'elevata suscettibilità delle cultivar Cellina di Nardò e Ogliarola salentina.

Se ha identificado un brote de Xylella fastidiosa en Apulia (al sureste de Italia) en olivos afectados por una nueva patología denominada síndrome del desecamiento rápido del olivo ("olive quick decline syndrome") (OQDS) que apareció de repente en 2010. La enfermedad puede ser el resultado de la acción combinada de X. fastidiosa con al menos otros dos organismos, la zeuzera (Zeuzera pyrina) y varias especies de hongos que habitan en la madera, principalmente Phoeachremonium parasiticum, (Nigro y col. 2013). Antes del descubrimiento de este brote en octubre 2013, X. fastidiosa era ampliamente conocida en el continente americano, donde al menos cuatro diferentes subespecies de esta bacteria han sido descritas y caracterizadas. Más recientemente se manifestó también en vid y peral en Taiwán. En estas zonas la bacteria es el agente causal de una serie de enfermedades de importancia económica, incluyendo la enfermedad de Pierce (PD) de la vid, la quemadura de la hoja del almendro y otros frutales de hueso, peral, adelfa y café, clorosis variegada de los cítricos (CVC), y otras enfermedades de plantas perennes y de forestales. Aunque la etiología de la nueva enfermedad del olivo todavía no ha sido determinada y probablemente implique al grupo de patógenos y plagas mencionadas anteriormente, el hallazgo de este organismo de cuarentena en la Unión Europea (Directiva 2000/29/EC) requiere de investigaciones urgentes para dar respuesta a las muchas preguntas abiertas. Según lo solicitado por la Unión Europea, tanto el Servicio Nacional como el Regional de Protección Vegetal de Italia están llevando a cabo acciones para su contención.

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.

Xylella fastidiosa (Xf) is a xylem-inhabiting, vectortransmitted bacterium and the agent of a variety of diseases in a broad range of plant hosts. A destructive Xf outbreak has recently emerged in some olive groves of the province of Lecce (south-eastern Italy), caused by a strain (called CoDiRO from the Italian for Rapid desiccation complex of olive) of Xf subsp. pauca, a pathogen known to infect coffee and citrus in South America. Taking into account that this is the first confirmed record of the presence of Xf in the European Union (EU) territory and fairing its possible spread from the affected site, the EU has issued the Commission Implementing Decision L 45/29-31 (February 24, 2014), which prohibits the transfer from the province of Lecce of all plant genera and species not listed in the Annex I of the cited Decision. A survey was therefore initiated to verify the health status of a number of ornamental and forestry plants growing mostly in nurseries, but also in public and private gardens, which are or can be naturally exposed to high inoculum pressure. Samples collected from 207 conifers, 105 members of the family Arecaceae, Musaceae and Cycadaceae, and 208 succulent plants (totalling 520) were comparatively examined by serological (DAS-ELISA) and molecular (PCR) methods. None of the tested plant species proved to be infected, providing a strong indication that they may not be susceptible to field infection by the Xf subsp. pauca strain currently present in the province of Lecce.

Xylella fastidiosa (Xf) was identified in September 2013 in olive trees affected by the Olive quick decline syndrome (OQDS) in the Salento peninsula (southern Italy) and denoted Xf strain CoDiRO. Xf is comprised of a group of genetically diverse bacteria in the class Gammaproteobacteria that causes severe plant diseases in many crops and ornamentals. The bacterium is acquired and transmitted by xylem-sap feeding hemipterans such as sharpshooter leafhoppers (Cicadellidae, Cicadellinae), froghoppers and spittlebugs (Aphrophoridae and Cercopidae) and, possibly, cicadas (Cicadidae and Tibicinidae.)

Xylella fastidiosa (Xf) was identified in September 2013 in olive trees affected by the Olive quick decline syndrome (OQDS) in the Salento peninsula (southern Italy) and denoted Xf strain CoDiRO. Xf is comprised of a group of genetically diverse bacteria in the class Gammaproteobacteria that causes severe plant diseases in many crops and ornamentals. The bacterium is acquired and transmitted by xylem-sap feeding hemipterans such as sharpshooter leafhoppers (Cicadellidae, Cicadellinae), froghoppers and spittlebugs (Aphrophoridae and Cercopidae) and, possibly, cicadas (Cicadidae and Tibicinidae.)

Oleander (Nerium oleander) is a host of different genotypes of Xylella fastidiosa (Xf) including the CoDiRO strain, which is associated with the quick decline syndrome of olive (OQDS) in the Salento peninsula, and was shown by MLST analysis to belong to the subspecies pauca, The CoDiRO strain, however, is molecularly distinct from the Xf pauca isolate reported from coffee and citrus, of which oleander is not a host.

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.

The CoDiRO strain of Xylella fastidiosa subsp. pauca (Xfp) is ravaging olive (Olea europaea) groves in southern Italy, causing a destructive disease denoted Olive Quick Decline Syndrome (OQDS). Field observations show that the Xfp-infected plants of the cv. Ogliarola salentina develop more severe symptoms than that of cv. Leccino. A global transcriptome profiling comparing the two olive cultivars, infected or not by Xfp, was performed to ascertain whether a tolerant condition of cv. Leccino exists, which could be exploited for lessening the economic impact of the disease on the local olive industry. The study revealed that 659 and 447 genes were differentially regulated upon Xfp infection, in cvs Leccino and Ogliarola salentina, respectively, whereas 512 genes resulted altered between the two infected cultivars. The analysis showed that plants of both cultivars perceive the presence of Xfp, mainly involving cell wall-associated proteins. The predominant response of cv. Leccino, which is missing in cv. Ogliarola salentina, consists on the up-regulation of genes encoding receptor-like kinases and receptor-like proteins. This different transcriptome response determines a lower pathogen concentration in the cv. Leccino, suggesting that it may harbor genetic constituents and/or regulatory elements which counteract Xfp infection. These findings suggest that cv. Leccino is endowed with an intrinsic tolerance to Xfp, which makes it eligible for further studies aimed at investigating molecular pathways underlying its different defense response.

The recent Xylella fastidiosa subsp. pauca (Xfp) outbreak in olive (Olea europaea) groves in southern Italy is causing a destructive disease denoted Olive Quick Decline Syndrome (OQDS). Field observations disclosed that Xfp-infected plants of cv. Leccino show much milder symptoms, than the more widely grown and highly susceptible cv. Ogliarola salentina. To determine whether these field observations underlie a tolerant condition of cv. Leccino, which could be exploited for lessening the economic impact of the disease on the local olive industry, transcriptional changes occurring in plants of the two cultivars affected by Xfp were investigated. Results: A global quantitative transcriptome profiling comparing susceptible (Ogliarola salentina) and tolerant (Leccino) olive cultivars, infected or not by Xfp, was done on messenger RNA (mRNAs) extracted from xylem tissues. The study revealed that 659 and 447 genes were differentially regulated in cvs Leccino and Ogliarola upon Xfp infection, respectively, whereas 512 genes were altered when the transcriptome of both infected cultivars was compared. Analysis of these differentially expressed genes (DEGs) shows that the presence of Xfp is perceived by the plants of both cultivars, in which it triggers a differential response strongly involving the cell wall. Up-regulation of genes encoding receptor-like kinases (RLK) and receptor-like proteins (RLP) is the predominant response of cv. Leccino, which is missing in cv. Ogliarola salentina. Moreover, both cultivars react with a strong re-modelling of cell wall proteins. These data suggest that Xfp elicits a different transcriptome response in the two cultivars, which determines a lower pathogen concentration in cv. Leccino and indicates that this cultivar may harbor genetic constituents and/or regulatory elements which counteract Xfp infection. Conclusions: Collectively these findings suggest that cv. Leccino is endowed with an intrinsic tolerance to Xfp, which makes it eligible for further studies aiming at investigating molecular basis and pathways modulating its different defense response.

A virus with filamentous articles ca. 700 nm long, denoted Fig latent virus 1 (FLV-1) is widespread in Apulian(southern Italy) fig orchards, in trees showing or not mosaic symptoms and in symptomless seedlings. The virus wastransmitted by sap inoculation to a very restricted range of herbaceous hosts without inducing apparent symptoms andwas transmitted through fig seeds to a very high percentage (80 to 100 %). It was successfully purified from root tissues of infected figs. A virus-specific antiserum raised in rabbits, proved useful for its detection in fig leaf dips byimmunosorbent electron microscopy (ISEM), Western Blot, dot immuno-binding (DIBA), ELISA.The viral genomestructure resembles that of members of the genus Trichovirus in the family Flexiviridae.

Una celebre frase recitava "a mi turba, sono uno scienziato", ma l'assenza di turbamento per i ricercatori sembra essere una prerogativa del passato. I 'processi alla scienza', dal caso dell'Aquila alla sperimentazione animale, campeggiano sui media e dominano il dibattito pubblico, talvolta a sostegno di una pericolosa delegittimazione. In questa nebulosa mediatica, le ragioni della ricerca rimangono spesso intrappolate tra i grovigli della politica e della magistratura, si scontrano con l'ignoranza diffusa e si contaminano a causa del complesso dialogo tra interlocutori molto diversi.