170 research outputs found

    First report of Southern tomato virus in tomato crops in Italy

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    Twenty-five tomato plants (Solanum lycopersicum) showing symptoms of viral disease were sampled from different greenhouses in the Ragusa province (Southern Italy) in summer 2015. Plants showed chlorosis on leaves and fruits and deformation and depressed spots of dark colour which later evolved into necrosis (Fig. 1). These symptoms were observed on the entire cluster of fruit making the product unsaleable. Based on these symptoms, samples were analysed for Cucumber mosaic virus, Pepino mosaic virus (PepMV), Potato virus Y (PVY), Tomato mosaic virus and Tomato spotted wilt virus by DAS-ELISA with polyclonal antibodies (Loewe Phytodiagnostica, Germany), and for the emerging Southern tomato virus (STV) by RT-PCR (Candresse et al., 2013). Three of the 25 samples analysed were positive only for PepMV whereas the rest of the samples had mixed infections: fifteen plants were co-infected with PepMV and PVY, and seven with STV, PepMV and PVY. The amplification product (894 bp) obtained from one STV-infected plant was purified using the UltraClean® PCR Clean-Up kit (Mo-Bio, USA) and the consensus nucleotide sequences were determined in both senses using an ABI 3130XL Genetic Analyzer (Life Technologies, USA) and deposited in GenBank under accession number KT948068. The nucleotide identity of the Italian STV isolate was greater than 99% with STV isolates Mexico1 (EF442780), BD-13 (KT634055), CN-12 (KT438549), MS7 (EU413670) and FR (KC333078) from Mexico, Bangladesh, China, USA and France, respectively

    First report of Tomato leaf curl Sinaloa virus infecting tomato crops in Panama

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    In April 2011 and September 2012, virus-like symptoms were observed in open field- and greenhouse-grown tomato crops (Solanum lycopersicum) in Chiriqu\ued, the westernmost province of Panama. Samples from symptom-bearing plants (127 in all) were collected and tested for the presence of begomoviruses by polymerase chain reaction (PCR) assays with sets of degenerated primers designed to amplify parts of the DNA-A and DNA-B components (Rojas et al., 1993; Table 1). Products of the expected sizes, obtained with both DNA-A- and DNA-B-specific primers for 49 samples, suggested infection with New World bipartite begomoviruses. This corresponds to an incidence of 26% (8 plants) in open field, and 43% (41 plants) in greenhouse crops. Primers specific for ten tomato-infecting begomoviruses found in Central America (Engel et al., 1998; Nakhla et al., 2005; Table 1) were used to typify the PCR-positive samples

    Proof of principle of a fuel injector based on a magnetostrictive actuator

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    One of the goals of modern internal combustion engines is the NOx-soot trade-off, and this would be better achieved by a better control of the fuel injection. Moreover, this feature can be also useful for high-performance hydraulic systems. Actual fuel injection technology either allows only the control of the injection time or it is based on very complex mechanical-hydraulic systems, as in the case of piezo-actuators. This work describes the basic steps that brought the authors to the realization of a concept fuel injector based on a Terfenol-D magnetostrictive actuator that could overcome the previous issues, being both simple and controllable. The study provides the design, development, and a feasibility analysis of a magnetostrictive actuator for fuel injection, by providing a basic magneto-static analysis of the actuator, the adaptation of a suitable standard fuel injector, and its experimental testing in a lab environment, with different shapes and amplitude of the reference signal to follow

    First report of Tomato leaf curl New Delhi virus affecting zucchini squash in an important horticultural area of southern Italy

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    omato leaf curl New Delhi virus (ToLCNDV) is a bipartite begomovirus (family Geminiviridae) which infects species in the families Cucurbitaceae and Solanaceae (Padidam et al., 1995; Mizutani et al., 2011). Begomoviruses are transmitted by the whitefly Bemisia tabaci in a persistent manner (Rosen et al., 2015). In October 2015, severe symptoms not previously reported by growers in the horticultural area of the Province of Trapani (Sicily, Italy) were observed on zucchini squash (Cucurbita pepo) in open fields. The symptoms included yellow mosaic, severe leaf curling, swelling of veins of young leaves, shortening of internodes, roughness of the skin of fruit and reduced fruit size; the symptoms were reminiscent of those caused by begomoviruses. Total DNA was extracted from young leaves of 22 plants by phenol/chloroform extraction and ethanol precipitation. PCR was performed with the A1F/A1R primer pair (Mizutani et al., 2011) for the DNA-A component and the pair described by Ruiz et al. (2015) for the DNA-B component to amplify a ~1200-bp fragment of DNA-A and a ~890 bp fragment of DNA-B, respectively. All 10 samples were positive by PCR with both primer pairs. No amplification products were obtained using primers specific for the monopartite begomoviruses Tomato yellow leaf curl virus and Tomato yellow leaf curl Sardinia virus (Davino et al., 2008). DAS-ELISA analysis for Cucumber mosaic virus, Papaya ring spot virus and Zucchini yellow mosaic virus (Loewe Phytodiagnostica, Germany) yielded negative results

    OCCURRENCE OF TOMATO LEAF CURL NEW DELHI VIRUS INFECTING ZUCCHINI IN SARDINIA (ITALY)

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    Tomato leaf curl New Delhi virus (ToLCNDV, genus Begomovirus) is a bipartite, circular, ssDNA virus, able to infect species within the Cucurbitaceae and Solanaceae. In August 2016, field observations carried out in Sardinia (Italy) highlighted in one location (Decimoputzu, CA) some plants of zucchini squash (Cucurbita pepo L.) showing a systemic disease never observed before, even in a previous survey (end-June 2016) on cucurbit viruses

    First Report of Tomato Leaf Curl New Delhi Virus Causing Yellow Leaf Curl of Pepper in Europe

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    Tomato leaf curl New Delhi virus (ToLCNDV), a bipartite begomovirus (family Geminiviridae) with two circular ssDNA genome components (DNA-A and DNA-B), is transmitted in a circulative nonpropagative manner by the whitefly Bemisia tabaci (Gennadius). Although it was first reported in Asia on tomato and other solanaceous crops such as eggplant, potato, and chilli pepper in the Mediterranean basin, this virus was mainly detected on cucurbits and only sporadically on tomato and on two wild solanaceous species, Datura stramonium L. and Solanum nigrum L. (Juárez et al. 2019). In 2018, separate surveys were carried out in protected cultivations of sweet pepper (Capsicum annuum L.) in two Italian regions: Lazio and Campania. The greenhouses were in areas with high density of B. tabaci and where ToLCNDV outbreaks occurred on cucurbits since 2016 (Panno et al. 2019). Some plants showing symptoms of yellowing and leaf curling were found in both regions, whereas fruit symptoms were neither observed nor reported by farmers. This disease syndrome, known as yellow leaf curl disease (YLCD), can be caused in pepper by several begomoviruses, as reported recently in a review listing the viruses causing YLCD in peppers in Thailand (Chiemsombat et al. 2018). Symptomatic leaves were collected during late summer 2018 from different pepper plants as well as from the neighboring zucchini cultivations, showing the typical symptomatology induced by ToLCNDV. Total DNA was extracted (DNeasy Plant Mini kit, Qiagen, Germany), and the presence of ToLCNDV was ascertained by PCR with the specific primers ToLCNDV-CP1 and ToLCNDV-CP2 (Panno et al. 2019; Parrella et al. 2018). ToLCNDV infection was further ascertained in three symptomatic leaf samples from Campania by using specific ToLCNDV ImmunoStrips (Agdia, Elkhart, IN). Successively, one symptomatic pepper sample from each greenhouse was selected and amplified by rolling circle amplification technique (RCA; Inoue-Nagata et al. 2004). The amplicons were cloned, and the DNA-A and DNA-B were full-length sequenced. The sequences were deposited in GenBank NCBI database (MK732932 DNA-A and MK732933 DNA-B, pepper sample from Campania; MK756106 DNA-A and MK756107 DNA-B, pepper sample from Lazio). The RCA analysis was performed also on a ToLCNDV-infected zucchini sample collected in the same area in Lazio region (MK756108 DNA-A and MK756109 DNA-B). The analysis of the ToLCNDV sequences showed a low level of genetic variability between the two pepper isolates from Lazio and Campania regions (rate of substitutions: 0.016 for DNA-A and 0.023 for DNA-B). A high genetic similarity was recorded between the zucchini isolate and both the pepper isolates from Campania (0.019 for DNA-A and 0.023 for DNA-B) and Lazio (0.003 for both DNA-A and B). The three characterized isolates showed a high sequence homology also with both the DNA-A (MH577751 from a melon isolate) and DNA-B (MH577673 from a zucchini isolate) of the ToLCNDV-ES genotype (Fortes et al. 2016), which differed in 15 and 13 nucleotide substitutions from pepper sample from Lazio, 29 and 51 substitutions from Campania sample, and 10 and 5 substitutions from zucchini sample. High homology was also identified compared with the other Spanish isolates collected since the first appearance of the virus (2014) and to the Tunisian (2015) and Moroccan (2018) isolates, confirming the hypothesis that the Mediterranean population of ToLCNDV is highly conserved (Juárez et al. 2019). To our knowledge, this is the first report of ToLCNDV infection on pepper in Europe and indicates that sweet pepper could also act as a reservoir of the virus for further spread to other solanaceous plants and cucurbits
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