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Citrus tristeza virus (CTV) populations in citrus trees are unusually complex mixtures of viral genotypes and defective RNAs developed during the long-term vegetative propagation of the virus and by additional mixing by aphid... more
Citrus tristeza virus (CTV) populations in citrus trees are unusually complex mixtures of viral genotypes and defective RNAs developed during the long-term vegetative propagation of the virus and by additional mixing by aphid transmission. The viral replication process allows the maintenance of minor amounts of disparate genotypes and defective RNAs in these populations. CTV is a member of the Closteroviridae possessing a positive-stranded RNA genome of ≈20 kilobases that expresses the replicase-associated genes as an ≈400-kDa polyprotein and the remaining 10 3′ genes through subgenomic mRNAs. A full-length cDNA clone of CTV was generated from which RNA transcripts capable of replication in protoplasts were derived. The large size of cDNA hampered its use as a genetic system. Deletion of 10 3′ genes resulted in an efficient RNA replicon that was easy to manipulate. To investigate the origin and maintenance of the genotypes in CTV populations, we tested the CTV replicase for its acce...
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The fusion sites between the termini of naturally occurring defective RNAs (D-RNAs) from three citrus tristeza virus (CTV) isolates were sequenced. Seven of eight clones showed a common 3' terminus of 940 nucleotides (nt) fused to... more
The fusion sites between the termini of naturally occurring defective RNAs (D-RNAs) from three citrus tristeza virus (CTV) isolates were sequenced. Seven of eight clones showed a common 3' terminus of 940 nucleotides (nt) fused to 5' termini with different sizes. An extra cytosine nucleotide was found at the junction site of the majority of the common 3' D-RNAs. Molecular analysis of the plus and minus strands of the 0.9-kbp double-stranded RNA, corresponding to the CTV open reading frame 11 subgenomic RNA (sgRNA), showed that they were identical in length and sequence to the common 3' sequence of the D-RNAs. These results imply that viral sgRNA messengers also function as building components for genomic rearrangement and exchange of complete viral genes.
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... No significant differences in leaf area were found 26 days and 2.5 months after inoculation (Table 1). However, the growth of leaf area and relative growth rate from 2.5 to 4 months were reduced by 16 ... We thank Suguru Sato and Y.... more
... No significant differences in leaf area were found 26 days and 2.5 months after inoculation (Table 1). However, the growth of leaf area and relative growth rate from 2.5 to 4 months were reduced by 16 ... We thank Suguru Sato and Y. Ben-Shalom for technical assistance and Drs. ...
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Virus diseases of perennial trees and vines have characteristics not amenable to study using small model annual plants. Unique disease symptoms such as graft incompatibilities and stem pitting cause considerable crop losses. Also, viruses... more
Virus diseases of perennial trees and vines have characteristics not amenable to study using small model annual plants. Unique disease symptoms such as graft incompatibilities and stem pitting cause considerable crop losses. Also, viruses in these long-living plants tend to accumulate complex populations of viruses and strains. Considerable progress has been made in understanding the biology and genetics of Citrus tristeza virus (CTV) and in developing it into a tool for crop protection and improvement. The diseases in tree and vine crops have commonalities for which CTV can be used to develop a baseline. The purpose of this review is to provide a necessary background of systems and reagents developed for CTV that can be used for continued progress in this area and to point out the value of the CTV-citrus system in answering important questions on plant-virus interactions and developing new methods for controlling plant diseases. Expected final online publication date for the Annual Review of Phytopathology Volume 53 is August 04, 2015. Please see http://www.annualreviews.org/catalog/pubdates.aspx for revised estimates.
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This is the standard and definitive reference for virus taxonomy, generated by the ICTV approximately every 3 years. The VIII ICTV Virus Taxonomy Report provides information on 3 orders of viruses, 73 families, 9 subfamilies, 287 genera... more
This is the standard and definitive reference for virus taxonomy, generated by the ICTV approximately every 3 years. The VIII ICTV Virus Taxonomy Report provides information on 3 orders of viruses, 73 families, 9 subfamilies, 287 genera and 1938 virus species, illustrated by more than 429 pictures and diagrams, most of them in color. * The standard official ITCV reference for virus taxonomy and nomenclature, compiling data from 500 international experts * Covers over 6000 recognized viruses, organized by family with diagrams of genome organization and virus replication cycle * Provides data on the phylogenic relationships between viruses belonging to the same or different taxa * Now includes information about the qualitative and quantitative relationships between virus sequences
Quantification of two plant viruses in suspensions of homoionic Ca-bentonite was conducted by applying to the enzyme-linked immunosorbent assay plates either the virus-clay mixture (direct method) or the supernatant obtained after the... more
Quantification of two plant viruses in suspensions of homoionic Ca-bentonite was conducted by applying to the enzyme-linked immunosorbent assay plates either the virus-clay mixture (direct method) or the supernatant obtained after the clay was allowed to settle (classic method). Both methods showed a similar dependence of free virus content on clay concentration. A higher content at equilibrium was measured for both viruses by the direct method. The advantage of using the direct over the classic method is discussed.
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Translation of capped and uncapped eukaryotic mRNAs is stimulated by addition of eIF-4B to an mRNA-dependent reticulocyte lysate system. m7G5 ppp inhibits translation of capped but not uncapped mRNAs and reduces translation of capped... more
Translation of capped and uncapped eukaryotic mRNAs is stimulated by addition of eIF-4B to an mRNA-dependent reticulocyte lysate system. m7G5 ppp inhibits translation of capped but not uncapped mRNAs and reduces translation of capped vaccinia mRNA to the level obtained with uncapped vaccinia mRNA. Exogenous eIF-4B but no other initiation factor reverses inhibition of protein synthesis by m7G5'ppp. Both capped and uncapped mRNAs interact directly with eIF-4B to form a stable complex, which can be detected by a simple nitrocellulose filter binding assay. However, addition of a 5'-cap to beta-eliminated globin mRNA or satellite tobacco necrosis virus RNA (normally uncapped) increased binding affinity of these mRNAs for eIF-4B and causes binding of these mRNAs to become sensitive to inhibition by m7G5'ppp. These results indicate that the role of the mRNA 5'-cap in translation is related specifically to the function of eIF-4B in forming a complex with mRNA (prior to assoc...
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... A, ROSNER*, B, RACCAH, M, L, MAYORAL, M, BAR-JOSEPH Virology Department, Agricultural Research Organization. ... These cloned sequences were shown to hybri-dize specifically with RNA extracted from puri-fied virus preparations and... more
... A, ROSNER*, B, RACCAH, M, L, MAYORAL, M, BAR-JOSEPH Virology Department, Agricultural Research Organization. ... These cloned sequences were shown to hybri-dize specifically with RNA extracted from puri-fied virus preparations and with intact virus particles ...
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Research Interests: Plant Biology and Tomato
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... Holger Puchta+, Karla Ramm, Renate Luckinger, Rivka Hadas1, Moshe Bar-Joseph1 and Heinz L.Sanger* Max Planck Institut fur Biochemie, D ... 'Etrog' citron plants inoculated with CVd IV alone displayed only transiently... more
... Holger Puchta+, Karla Ramm, Renate Luckinger, Rivka Hadas1, Moshe Bar-Joseph1 and Heinz L.Sanger* Max Planck Institut fur Biochemie, D ... 'Etrog' citron plants inoculated with CVd IV alone displayed only transiently mild symptoms of leaf epinasty after hot summer weather. ...
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... 294 IS BEN-ZE'EV, M. BAR-JOSEPH, Y. NITZAN AND RUTH MARCUS ... Indexing CTV isolates by chip-bud grafting Chip buds from twigs of selected collapsing 'Minneola' trees were grafted on seedlings of the... more
... 294 IS BEN-ZE'EV, M. BAR-JOSEPH, Y. NITZAN AND RUTH MARCUS ... Indexing CTV isolates by chip-bud grafting Chip buds from twigs of selected collapsing 'Minneola' trees were grafted on seedlings of the standard CTV indicators: lime (Citrus aurantifolia) and allemow (C ...
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ABSTRACT
Two representative isolates of a citrus tristeza virus population in Sicily, SG29 (aggressive) and Bau282 (mild), were sequenced via viral small RNAs (vsRNA) produced in budlings of sweet orange grafted on sour orange. Phylogenetic... more
Two representative isolates of a citrus tristeza virus population in Sicily, SG29 (aggressive) and Bau282 (mild), were sequenced via viral small RNAs (vsRNA) produced in budlings of sweet orange grafted on sour orange. Phylogenetic relationships with Mediterranean and exotic isolates revealed that SG29 clustered within the "VT-Asian" subtype, whereas Bau282 belonged to the cluster T30. The study confirms that molecular data need to be integrated with bio-indexing in order to obtain adequate information for risk assessment.
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In this study, the distribution of CTV in citrus groves in Israel is considered using the data gathered from the CTV survey during the period 1979–1985. A theoretical curve is fitted to the distribution of the number of infected trees in... more
In this study, the distribution of CTV in citrus groves in Israel is considered using the data gathered from the CTV survey during the period 1979–1985. A theoretical curve is fitted to the distribution of the number of infected trees in infected plots which contain at least a single infected tree. Some recommendations for improving the sampling method for locating
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Immunocapture reverse transcription coupled with PCR (RT-PCR). The CTV particles adsorbed from infected tissue to the ELISA plates were used for RT-PCR, using a modification of the procedure by Noiasco et al (18). After reading the color... more
Immunocapture reverse transcription coupled with PCR (RT-PCR). The CTV particles adsorbed from infected tissue to the ELISA plates were used for RT-PCR, using a modification of the procedure by Noiasco et al (18). After reading the color reac-tions, the plates were washed once ...
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Isolates of the Closterovirus, Citrus tristeza virus (CTV), are populations of disparate genotypes and defective RNAs developed during long periods of vegetative propagation of citrus trees. Because it has not been possible to obtain pure... more
Isolates of the Closterovirus, Citrus tristeza virus (CTV), are populations of disparate genotypes and defective RNAs developed during long periods of vegetative propagation of citrus trees. Because it has not been possible to obtain pure cultures of the virus, it is not known what ...
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ABSTRACT Seven monoclonal antibodies (MAbs) showing homologous reactions with the VT strain of citrus tristeza virus (CTV) were tested against 21 CTV strains or isolates, representing the range of biological diversity and the geographical... more
ABSTRACT Seven monoclonal antibodies (MAbs) showing homologous reactions with the VT strain of citrus tristeza virus (CTV) were tested against 21 CTV strains or isolates, representing the range of biological diversity and the geographical distribution of CTV in Israel. All the CTV strains gave positive reactions in ELISA with polyclonal antibodies and with one MAb (#25#2). Two MAbs; #13#21 and #3/7 reacted with 19 and 12 out of the 21 CTV strains, respectively. Seventeen CTV strains, including all those previously assigned by sequencing their coat protein gene (CPG) to the CPG-VT group (Mawassi, Gafny & Bar-Joseph, 1993), reacted with five or more MAbs. Four CTV strains of minor epidemiological importance, including two members of the CPG-MT group, did not react with five or more of the MAbs. These results indicated the existence of two serogroups of Israeli CTV strains that can be differentiated by MAbs and which closely correlate with and extend the previous CPG grouping. The extensive biological variation within each CPG group confirms recent analyses suggesting that the CTV pathogenic traits are not necessarily associated with a sequence or antigenic variation of the CTV-CPG.