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Ceglie Messapica, Italy

Matic S.,CNR Institute of Plant virology | Elmaghraby I.,Istituto Agronomico Mediterraneo | Elmaghraby I.,University of Padua | Law V.,Canadian Food Inspection Agency | And 4 more authors.
Journal of Plant Pathology | Year: 2011

Sixteen isolates of Plum pox virus (PPV) were collected during a survey in the Egyptian areas of Sinro and Apoxa (El Fayoum) and El Amar (Nile Delta). All isolates reacted with the universal PPV monoclonal antibody MAb 5B and were identified as PPV strain EA by phylogenetic analysis of the full-length sequence of the coat protein (CP) gene. This classification was confirmed by detection with the strain-specific MAb EA24, except for an isolate denoted APR 50. Detailed analysis of the CP amino acid sequence of the EA isolates and epitope mapping revealed that histidine at amino acid position 65 of the CP sequence is an essential component of the epitope required for MAb EA24 recognition. APR 50 has an arginine substitution at this position. Five EA serogroups were identified, serogroup I being the prevailing one with 10 of the 14 isolates characterized. Moderate serological and relatively high genetic diversity was observed among isolates of PPV-EA. The most variable isolate, APR 48, contained a deletion of 33 nucleotides at the 5' terminus of the CP gene. The relatively high genetic diversity of PPV-EA suggests that it is not a recent introduction. Source

Hancevic K.,Institute for Adriatic Crops | Cerni S.,University of Zagreb | Nolasco G.,University of Algarve | Radic T.,Institute for Adriatic Crops | And 2 more authors.
Physiological and Molecular Plant Pathology | Year: 2013

Citrus tristeza virus (CTV) is the most destructive viral pathogen of citrus and displays a high level of genetic and phenotypic diversity. In this study the biological characterization of monophyletic CTV-isolates based on p25 gene (Gp 1, Gp 2, Gp 3a, Gp 4, Gp 5, Gp M) was analyzed for the first time on the set of standard indicator plants and unde r the same environmental conditions, in order to compare the phenotypic characteristics of p25 genomic variants. The results showed that tested CTV-isolates varied in their ability to induced symptoms as well as in severity of symptoms e.g. pathogenicity. © 2012 Elsevier Ltd. Source

Elbeaino T.,Istituto Agronomico Mediterraneo | Kubaa R.A.,Istituto Agronomico Mediterraneo | Choueiri E.,Lebanese Agricultural Research Institute | Digiaro M.,Istituto Agronomico Mediterraneo | Navarro B.,CNR Institute of Plant virology
Journal of Phytopathology | Year: 2012

The presence of Hop stunt viroid (HSVd) was detected using RT-PCR and Northern blot hybridization in five of 60 samples from symptomless mulberry trees (Morus alba) collected in Italian and Lebanese orchards in July 2010. Infection levels were c. 10% in Lebanese and 8% in Italian samples. Nucleotide alignments showed that sequences of the mulberry HSVd isolates shared 95-96% identity with those of the same viroid occurring elsewhere. In a phylogenetic tree, mulberry HSVd isolates clustered together with those of HSVd-citrus, regardless of their geographical origin. This is the first report of infection in mulberry trees by HSVd. © 2011 Blackwell Verlag GmbH. Source

Molinari S.,CNR Plant Protection Institute | Baser N.,Istituto Agronomico Mediterraneo
Crop Protection | Year: 2010

Different concentrations of the systemic acquired resistance (SAR) elicitors, salicylic acid (SA), methyl-salicylic acid (MetSA), acibenzolar-S-methyl (ASM) and 2,6-dicholoroisonicotinic acid (INA), were provided to tomato seedlings as root-dip or soil-drench one day before inoculation with the root-knot nematode, Meloidogyne incognita. Nematode infestation was evaluated by counting egg masses/plant (EM), eggs/plant (Pf), and sedentary forms/plant (SF) in treated and untreated plants seven weeks after inoculation. An index of plant fitness (PF) was also calculated to assess the costs of chemically-induced resistance and the possible phytotoxicity of the treatments. SA and ASM were found to be effective elicitors of resistance when applied at suitable concentrations and method of application. Soil-drench with SA and root-dip in ASM were the most effective treatments as they markedly reduced both nematode reproduction (less than 50% that of untreated plants) and infestation (50-70% EM reduction). MetSA was less effective than SA in eliciting resistance because of its negative effects on plant fitness when it was provided as soil-drench. INA did not reduce nematode infestation at any of the non-phytotoxic rates. The reduction of nematode infestation and reproduction by SA applied as soil-drench was potentiated when the soil was enriched with humic acids. Soil-drenching with SA and MetSA were the only treatments that caused a long-lasting induction of plant defences as they inhibited the infestation by the second generation of the nematode. © 2010 Elsevier Ltd. Source

Elbeaino T.,Istituto Agronomico Mediterraneo | Digiaro M.,Istituto Agronomico Mediterraneo | Uppala M.,Indian International Crops Research Institute for the Semi Arid Tropics | Sudini H.,Indian International Crops Research Institute for the Semi Arid Tropics
Archives of Virology | Year: 2015

Deep-sequencing analysis of double-stranded RNA extracted from a mosaic-diseased pigeonpea plant (Cajanus cajan L., family Fabaceae) revealed the complete sequence of six emaravirus-like negative-sense RNA segments of 7009, 2229, 1335, 1491, 1833 and 1194 nucleotides in size. In the order from RNA1 to RNA6, these genomic RNAs contained ORFs coding for the RNA-dependent RNA polymerase (RdRp, p1 of 266 kDa), the glycoprotein precursor (GP, p2 of 74.5 kDa), the nucleocapsid (NC, p3 of 34.9 kDa), and the putative movement protein (MP, p4 of 40.7 kDa), while p5 (55 kDa) and p6 (27 kDa) had unknown functions. All RNA segments showed distant relationships to viruses of the genus Emaravirus, and in particular to pigeonpea sterility mosaic virus (PPSMV), with which they shared nucleotide sequence identity ranging from 48.5 % (RNA3) to 62.5 % (RNA1). In phylogenetic trees constructed from the sequences of the proteins encoded by RNA1, RNA2 and RNA3 (p1, p2 and p3), this new viral entity showed a consistent grouping with fig mosaic virus (FMV) and rose rosette virus (RRV), which formed a cluster of their own, clearly distinct from PPSMV-1. In experimental greenhouse trials, this novel virus was successfully transmitted to pigeonpea and French bean seedlings by the eriophyid mite Aceria cajani. Preliminary surveys conducted in the Hyderabad region (India) showed that the virus in question is widespread in pigeonpea plants affected by sterility mosaic disease (86.4 %) but is absent in symptomless plants. Based on molecular, biological and epidemiological features, this novel virus is the second emaravirus infecting pigeonpea, for which the provisional name pigeonpea sterility mosaic virus 2 (PPSMV-2) is proposed. © 2015, Springer-Verlag Wien. Source

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