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Kubaa R.A.,University of Bari | Kubaa R.A.,CIHEAM Mediterranean Agronomic Institute | D'onghia A.M.,CIHEAM Mediterranean Agronomic Institute | Djelouah K.,CIHEAM Mediterranean Agronomic Institute | And 3 more authors.
Phytopathologia Mediterranea | Year: 2012

Citrus tristeza virus (CTV) is the causal agent of the most important virus disease of citrus. CTV isolates differing in biological and molecular characteristics have been reported worldwide. Recently, CTV was detected in Syria in citrus groves from two Governorates (Lattakia and Tartous) and several CTV outbreaks have been reported in Apulia (southern Italy) since 2003. To molecularly characterize the CTV populations spreading in Syria and Italy, a number of isolates from each region was selected and examined by different molecular approaches including: Multiple Molecular Markers analysis (MMM), real time RT-(q)PCR, single strand conformation polymorphism (SSCP) of the major coat protein (CP) gene (P25), and sequence analysis of the CP (P25), P18, P20 and RdRp genes. SSCP analysis of CP25 yielded two distinct simple patterns among the Syrian isolates and three different patterns in the Italian isolates. Based on MMM analysis, all Syrian CTV isolates were categorized as VT-like genotype, whereas the Italian isolates reacted only with the markers specific for the T30 genotype. These findings were also confirmed by RT-qPCR and by sequencing analysis of four genomic regions. The Italian isolates had nucleotide identities which varied: from 99.5 to 99.8 for the CP gene; from 97.4% to 98.3% for the P18 gene; from 98.6% to 99.8% for the P20 and from 97.8% to 99.1% for the partial RdRp sequenced. High sequence identity was found for all genomic regions analyzed between the Syrian isolates (from 98.9% to 99.6%). These results show that the CTV populations spreading in Apulia and Syria are associated with different genotypes, indicating different potential impacts on the citrus trees in the field. Since in both areas the introduction of the virus is relatively recent, infected plants resulted to contain a single and common genotype, suggesting that CTV is spreading from the first outbreaks by aphids or local movement of autochthonous infected plant material. © Firenze University Press.

Abou Kubaa R.,CIHEAM Mediterranean Agronomic Institute | Saleh S.,CIHEAM Mediterranean Agronomic Institute | Kumari S.,Agricultural Research Center in Lattakia | El Khateeb A.,International Center for Agricultural Research in the Dry Areas | Djelouah K.,CIHEAM Mediterranean Agronomic Institute
Journal of Plant Pathology | Year: 2014

Citrus psorosis virus (CPsV) is one of the oldest known graft-transmissible viruses of citrus. It causes typical bark scaling lesions in the trunk and limb of sweet orange, mandarin, grapefruit and other citrus spp. During spring 2011, a total of 250 symptomatic and asymptomatic trees, including 100 from a mother block in Lattakia governorate and 150 from six commercial orchards located in Jableh, Tartous and Lattakia areas were sampled to assess the presence of CPsV. All collected samples were analyzed by DAS-ELISA according to Potere et al. (1999) using a commercial kit (Agritest, Italy). Results indicated the presence of CPsV in two Navel Orange trees located in Lattakia. The presence of CPsV was confirmed in these trees by reverse transcription polymerase chain reaction (RT-PCR) using primers consF (5′- ACAAAGAAATTCCCTGCAAGGG-3′) and consR (5′-AAGTTTCTATCATTCTGAAACCC-3′) that target part of the CPsV coat protein gene (Roy et al., 2005) with the amplification of the expected size (411 bp) DNA product. The RT-PCR product was cloned and sequenced. The sequence of CPsV isolate SYR-C7 (GenBank accession No. HG964696) showed 97% nucleotide identity with Italian CPsV isolates (GenBank accession Nos AM235964 and AY194917). Symptoms associated to CPsV were observed in Syria (Bové, 1995) but the causal agent had yet to be identified. To our knowledge, this is the first CPsV detection in Syria by serological and molecular assays. © 2014, Edizioni ETS. All rights reserved.

Yaseen T.,CIHEAM Mediterranean Agronomic Institute | Ricelli A.,CNR Institute of Neuroscience | Turan B.,CIHEAM Mediterranean Agronomic Institute | Albanese P.,CIHEAM Mediterranean Agronomic Institute | D'Onghia A.M.,CIHEAM Mediterranean Agronomic Institute
Phytopathologia Mediterranea | Year: 2015

Different biotic contaminations can affect apple production. Among these, infections by Penicillium expansum, the causal agent of blue-green post-harvest rot and patulin production, is particularly important. Fruit of the apple varieties: 'Royal Gala', 'Golden Delicious' and 'Fuji' were challenged with a patulin-producing P. expansum strain and stored at 1 ± 1°C in presence of gaseous ozone at 0.5 μL L-1 for 2 months. During the storage period, fungal populations, the biosynthesis of patulin and the activity of some Pathogenesis Related Proteins (glucanase, peroxidase and phenylalanine ammonia-lyase) were evaluated. Ozone treatment reduced fungal populations and patulin production. The activity of the assayed enzymes was not directly or clearly correlated with the inhibiting effect of ozone. These results indicate that ozone could be used to increase storage duration of apple varieties to maintain their quality. © Firenze University Press.

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