Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
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| development of multiplex pcr for simultaneous detection of citrus viruses and the incidence of citrus viral diseases in late-maturity citrus trees in jeju island. | satsuma dwarf virus (sdv) or citrus mosaic sadwavirus (cimv) were not consistently detected in rt-pcr assay with the primer sets based on gene of japan isolates. sdv and cimv isolates were distinctively divided into two groups based on phylogenetic analysis of pp2 gene cloned from 22 korean isolates, and the korean cimv and sdv isolates shared 95.5-96.2% and 97.1-97.7% sequence identity with japanese isolate, respectively. we developed pp2-1 primer set based on the pp2 gene sequence of korean is ... | 2017 | 28592949 |
| in silico probe-based detection of citrus viruses in ngs data. | the conservation of plant biosecurity relies on the rapid identification of pathogenic organisms, including viruses. with next-generation sequencing (ngs), it is possible to identify multiple viruses within a metagenomic sample. in this study, we explored the use of electronic probes (e-probes) for the simultaneous detection of 11 recognized citrus viruses. e-probes were designed and screened against raw sequencing data to minimize the bioinformatic processing time required. the e-probes were ab ... | 2017 | 28562184 |
| identification and characterization of citrus tristeza virus isolates breaking resistance in trifoliate orange in california. | most citrus tristeza virus (ctv) isolates in california are biologically mild and symptomless in commercial cultivars on ctv tolerant rootstocks. however, to better define california ctv isolates showing divergent serological and genetic profiles, selected isolates were subjected to deep sequencing of small rnas. full-length sequences were assembled, annotated and trifoliate orange resistance-breaking (rb) isolates of ctv were identified. phylogenetic relationships based on their full genomes pl ... | 2017 | 28453412 |
| deep sequencing analysis of rnas from citrus plants grown in a citrus sudden death-affected area reveals diverse known and putative novel viruses. | citrus sudden death (csd) has caused the death of approximately four million orange trees in a very important citrus region in brazil. although its etiology is still not completely clear, symptoms and distribution of affected plants indicate a viral disease. in a search for viruses associated with csd, we have performed a comparative high-throughput sequencing analysis of the transcriptome and small rnas from csd-symptomatic and -asymptomatic plants using the illumina platform. the data revealed ... | 2017 | 28441782 |
| disulfide-induced self-assembled targets: a novel strategy for the label free colorimetric detection of dnas/rnas via unmodified gold nanoparticles. | a modified non-cross-linking gold-nanoparticles (au-nps) aggregation strategy has been developed for the label free colorimetric detection of dnas/rnas based on self-assembling target species in the presence of thiolated probes. two complementary thiol- modified probes, each of which specifically binds at one half of the target introduced sh groups at both ends of dsdna. continuous disulfide bond formation at 3' and 5' terminals of targets leads to the self-assembly of dsdnas into the sulfur- ri ... | 2017 | 28387331 |
| self-interaction of citrus tristeza virus p33 protein via n-terminal helix. | citrus tristeza virus (ctv), the most economically important viral pathogen of citrus, encodes a unique protein, p33. ctv p33 shows no similarity with other known proteins, yet plays an important role in viral pathogenesis: it extends the virus host range and mediates virus ability to exclude superinfection by other variants of the virus. previously we demonstrated that p33 is an integral membrane protein and appears to share characteristics of viral movement proteins. in this study, we show tha ... | 2017 | 28279804 |
| the enemy within: phloem-limited pathogens. | the growing impact of phloem-limited pathogens on high-value crops has led to a renewed interest in understanding how they cause disease. although these pathogens cause substantial crop losses, many are poorly characterized. in this review, we present examples of phloem-limited pathogens that include intracellular bacteria with and without cell walls, and viruses. phloem-limited pathogens have small genomes and lack many genes required for core metabolic processes, which is, in part, an adaptati ... | 2016 | 27997761 |
| population structure and diversity of citrus tristeza virus (ctv) isolates in hunan province, china. | stem-pitting (sp) is the main type of citrus tristeza virus (ctv) that causes severe damage to citrus trees, especially those of sweet orange, in hunan province, china. understanding the local ctv population structure should provide clues for effective mild strain cross-protection (mscp) of the sp strain of ctv. in this study, markers for the p23 gene, multiple molecular markers (mmms), and sequence analysis of the three silencing suppressor genes (p20, p23 and p25) were employed to analyze the ... | 2017 | 27771790 |
| understanding superinfection exclusion by complex populations of citrus tristeza virus. | superinfection exclusion (sie) is a phenomenon in which a primary viral infection restricts a secondary infection with the same or closely related virus. previously we showed that sie by citrus tristeza virus (ctv) occurs only between isolates of the same virus genotype. this work, however, was done using single genotype-containing isolates, while most field citrus trees harbor complex populations composed of different virus genotypes. here we examined sie in plants simultaneously infected with ... | 2016 | 27743959 |
| some like it hot: citrus tristeza virus strains react differently to elevated temperature. | viruses often infect plants as a mixed population. the dynamics of viral populations dictate the success of the infection, yet there is little understanding of the factors that influence them. it is known that temperature can affect individual viruses; could it also affect a virus population? in order to study this, we observed citrus tristeza virus (ctv) populations in different hosts under winter and summer conditions (25 versus 36 °c). we found that only some ctv strains were affected by a hi ... | 2016 | 27659675 |
| sequence variation in two genes determines the efficacy of transmission of citrus tristeza virus by the brown citrus aphid. | vector transmission is an important part of the viral infection cycle, yet for many viruses little is known about this process, or how viral sequence variation affects transmission efficacy. here we examined the effect of substituting genes from the highly transmissible fs577 isolate of citrus tristeza virus (ctv) in to the poorly transmissible t36-based infectious clone. we found that introducing p65 or p61 sequences from fs577 significantly increased transmission efficacy. interestingly, repla ... | 2016 | 27644950 |
| pcr bias associated with conserved primer binding sites, used to determine genotype diversity within citrus tristeza virus populations. | citrus tristeza virus (ctv) is present in almost all of the major citrus production areas where it continues to reduce the profitability of citriculture. the accurate characterisation of ctv populations, which are usually made up of a number of disparate strains, requires the use of robust pcr protocols. mismatches between primers and their corresponding binding sites may introduce primer-associated bias during amplification. the primer-associated bias of four sets of ctv specific primers, targe ... | 2016 | 27599411 |
| comparison of multiple viral population characterization methods on a candidate cross-protection citrus tristeza virus (ctv) source. | citrus tristeza virus (ctv) is the most economically important virus found on citrus and influences production worldwide. the 3' half of the rna genome is generally conserved amongst sources, whereas the 5' portion is more divergent, allowing for the classification of the virus into a number of genotypes based on sequence diversity. the acknowledged genotypes of ctv are continually being expanded, and thus far include t36, t30, t3, vt, b165, ha16-5, t68 and rb. the genotype composition of the ct ... | 2016 | 27599410 |
| the resistance of sour orange to citrus tristeza virus is mediated by both the salicylic acid and rna silencing defence pathways. | citrus tristeza virus (ctv) induces in the field the decline and death of citrus varieties grafted on sour orange (so) rootstock, which has forced the use of alternative decline-tolerant rootstocks in affected countries, despite the highly desirable agronomic features of the so rootstock. declining citrus plants display phloem necrosis below the bud union. in addition, so is minimally susceptible to ctv compared with other citrus varieties, suggesting partial resistance of so to ctv. here, by si ... | 2016 | 27588892 |
| minor coat and heat shock proteins are involved in the binding of citrus tristeza virus to the foregut of its aphid vector, toxoptera citricida. | vector transmission is a critical stage in the viral life cycle, yet for most plant viruses how they interact with their vector is unknown or is explained by analogy with previously described relatives. here we examined the mechanism underlying the transmission of citrus tristeza virus (ctv) by its aphid vector, toxoptera citricida, with the objective of identifying what virus-encoded proteins it uses to interact with the vector. using fluorescently labeled virions, we demonstrated that ctv bind ... | 2016 | 27520823 |
| monoclonal antibody-based serological methods for detecting citrus tristeza virus in citrus groves. | citrus tristeza virus (ctv) is one of the most economically important citrus viruses and harms the citrus industry worldwide. to develop reliable and effective serological detection assays of ctv, the major capsid protein (cp) gene of ctv was expressed in escherichia coli bl21 (de3) using the expression vector pet-28a and purified through ni+-nta affinity chromatography. the recombinant protein was used to immunize balb/c mice. four hybridoma cell lines (14b10, 14h11, 20d5, and 20g12) secreting ... | 2016 | 27405929 |
| detection of citrus tristeza virus by using fluorescence resonance energy transfer-based biosensor. | due to the low titer or uneven distribution of citrus tristeza virus (ctv) in field samples, detection of ctv by using conventional detection techniques may be difficult. therefore, in the present work, the cadmium-telluride quantum dots (qds) was conjugated with a specific antibody against coat protein (cp) of ctv, and the cp were immobilized on the surface of gold nanoparticles (aunps) to develop a specific and sensitive fluorescence resonance energy transfer (fret)-based nanobiosensor for det ... | 2016 | 27380305 |
| synthesis and assessment of dna/silver nanoclusters probes for optimal and selective detection of tristeza virus mild strains. | citrus tristeza virus (ctv) is one of the most destructive pathogens worldwide that exist as a mixture of malicious (sever) and tolerable (mild) strains. mild strains of ctv can be used to immunize healthy plants from more severe strains damage. recently, innovative methods based on the fluorescent properties of dna/silver nanoclusters have been developed for molecular detection purposes. in this study, a simple procedure was followed to create more active dna/agncs probe for accurate and select ... | 2016 | 27349801 |
| development of multiplex polymerase chain reaction assay for simultaneous detection of clostero-, badna- and mandari-viruses along with huanglongbing bacterium in citrus trees. | citrus trees harbor a large number of viral and bacterial pathogens. citrus yellow vein clearing virus (cyvcv), indian citrus ringspot virus (icrsv), citrus yellow mosaic virus (cymv), citrus tristeza virus (ctv) and a bacterium, candidatus liberibacter asiaticus (cla) associated with huanglongbing (hlb) disease, the most prevalent pathogens in citrus orchards of different regions in india and are responsible for debilitating citriculture. for detection of these viral and bacterial pathogens a q ... | 2016 | 27208471 |
| transcriptome analysis of sweet orange trees infected with 'candidatus liberibacter asiaticus' and two strains of citrus tristeza virus. | huanglongbing (hlb) and tristeza, are diseases of citrus caused by a member of the α-proteobacteria, 'candidatus liberibacter asiaticus' (calas), and citrus tristeza virus (ctv) respectively. hlb is a devastating disease, but ctv strains vary from very severe to very mild. both calas and ctv are phloem-restricted. the calas-b232 strain and ctv-b6 cause a wide range of severe and similar symptoms. the mild strain ctv-b2 doesn't induce significant symptoms or damage to plants. | 2016 | 27169471 |
| identification, characterization and functional analysis of a chitin synthase gene in the brown citrus aphid, toxoptera citricida (hemiptera, aphididae). | chitin synthase (chs) is a crucial enzyme involved in the final step of the insect chitin biosynthetic pathway. in this study, we cloned the full-length cdna sequence of a chitin synthase gene (tcichs) from the brown citrus aphid, toxoptera citricida, an important citrus pest and the main vector of citrus tristeza virus worldwide. tcichs was expressed during the entire lifecycle and in all insect tissues examined. expression was highest in first-second-instar nymphs, nymph-adult transitions and ... | 2016 | 26991909 |
| simultaneous visualization of two citrus tristeza virus genotypes provides new insights into the structure of multi-component virus populations in a host. | complex citrus tristeza virus (ctv) populations composed of mixtures of different strains of the virus are commonly found in citrus trees in the field. at present, little is known about how these populations are formed, maintained, and how they are structured within a host. here we used a novel in situ hybridization approach allowing simultaneous visualization of two different rna targets with high sensitivity and specificity to examine the distribution of two isolates, t36 and t68-1, representi ... | 2016 | 26874013 |
| a 5'-proximal region of the citrus tristeza virus genome encoding two leader proteases is involved in virus superinfection exclusion. | superinfection exclusion (sie), a phenomenon in which a primary virus infection prevents a secondary infection with the same or closely related virus, has been observed with various viruses. earlier we demonstrated that sie by citrus tristeza virus (ctv) requires viral p33 protein. in this work we show that p33 alone is not sufficient for virus exclusion. to define the additional viral components that are involved in this phenomenon, we engineered a hybrid virus in which a 5'-proximal region in ... | 2016 | 26748332 |
| reference gene validation for quantitative pcr under various biotic and abiotic stress conditions in toxoptera citricida (hemiptera, aphidiae). | the regulation of mrna expression level is critical for gene expression studies. currently, quantitative reverse transcription polymerase chain reaction (qrt-pcr) is commonly used to investigate mrna expression level of genes under various experimental conditions. an important factor that determines the optimal quantification of qrt-pcr data is the choice of the reference gene for normalization. to advance gene expression studies in toxoptera citricida (kirkaldy), an important citrus pest and a ... | 2015 | 26470351 |
| rootstock-scion interaction affecting citrus response to ctv infection: a proteomic view. | citrus tristeza virus (ctv) is the causal agent of various diseases with dramatic effects on citrus crops worldwide. most citrus species, grown on their own roots, are symptomless hosts for many ctv isolates. however, depending on different scion-rootstock combination, ctv infection should result in distinct syndromes, being 'tristeza' the more severe one, leading to a complete decline of the susceptible plants in a few weeks. transcriptomic analyses revealed several genes involved either in def ... | 2016 | 26459956 |
| finding balance: virus populations reach equilibrium during the infection process. | virus populations, mixtures of viral strains or species, are a common feature of viral infection, and influence many viral processes including infection, transmission, and the induction of disease. yet, little is known of the rules that define the composition and structure of these populations. in this study, we used three distinct strains of citrus tristeza virus (ctv) to examine the effect of inoculum composition, titer, and order, on the virus population. we found that ctv populations stabili ... | 2015 | 26291064 |
| the conundrum of a unique protein encoded by citrus tristeza virus that is dispensable for infection of most hosts yet shows characteristics of a viral movement protein. | citrus tristeza virus (ctv), one of the most economically important viruses, produces a unique protein, p33, which is encoded only in the genomes of isolates of ctv. recently, we demonstrated that membrane association of the p33 protein confers virus ability to extend its host range. in this work we show that p33 shares characteristics of viral movement proteins. upon expression in a host cell, the protein localizes to plasmodesmata and displays the ability to form extracellular tubules. further ... | 2015 | 26210077 |
| citrus tristeza virus (ctv) causing proteomic and enzymatic changes in sweet orange variety "westin". | citrus tristeza disease, caused by ctv (citrus tristeza virus), committs citrus plantations around the world and specifically attacks phloem tissues of the plant. the virus exists as a mixture of more or less severe variants, which may or may not cause symptoms of tristeza. the objective of this study was to analyze the changes caused by ctv in the proteome of stems of sweet orange, as well as in the activity and gene expression of antioxidant enzymes. the ctv-infected sweet orange displayed mil ... | 2015 | 26207751 |
| phylogenetic studies of the three rna silencing suppressor genes of south american ctv isolates reveal the circulation of a novel genetic lineage. | citrus tristeza virus (ctv) is the most economically important virus of citrus worldwide. genetic diversity and population structure of ctv isolates from all citrus growing areas from uruguay were analyzed by rt-pcr and cloning of the three rna silencing suppressor genes (p25, p20 and p23). bayesian phylogenetic analysis revealed the circulation of three known genotypes (vt, t3, t36) in the country, and the presence of a new genetic lineage composed by isolates from around the world, mainly from ... | 2015 | 26205407 |
| deep sequencing and analysis of small rnas in sweet orange grafted on sour orange infected with two citrus tristeza virus isolates prevalent in sicily. | 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 info ... | 2015 | 26175068 |
| citrus tristeza virus: making an ally from an enemy. | 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 impr ... | 2015 | 25973695 |
| development and validation of a multiplex reverse transcription quantitative pcr (rt-qpcr) assay for the rapid detection of citrus tristeza virus, citrus psorosis virus, and citrus leaf blotch virus. | a single real-time multiplex reverse transcription quantitative polymerase chain reaction (rt-qpcr) assay for the simultaneous detection of citrus tristeza virus (ctv), citrus psorosis virus (cpsv), and citrus leaf blotch virus (clbv) was developed and validated using three different fluorescently labeled minor groove binding qpcr probes. to increase the detection reliability, coat protein (cp) genes from large number of different isolates of ctv, cpsv and clbv were sequenced and a multiple sequ ... | 2015 | 25907469 |
| spatial and temporal spread of citrus tristeza virus and its aphid vectors in the north western area of morocco. | first report of citrus tristeza virus (ctv,closterovirus) in morocco datesback to 1961 in collections of citrus varieties. an exhaustive survey of citrus in the north of the country in 2009 revealed that ctv was spread all over the citrus production area. we attempted to evaluate the relative contribution of different aphid species in the spread of ctv disease in a citrus reticulata orchard at the loukkous region during 2 years (2012 and 2013). the overall ctv incidence estimated in the experime ... | 2016 | 25884375 |
| membrane association of a nonconserved viral protein confers virus ability to extend its host range. | citrus tristeza virus (ctv), the largest and most complex member of the family closteroviridae, encodes a unique protein, p33, which shows no homology with other known proteins, however, plays an important role in virus pathogenesis. in this study, we examined some of the characteristics of p33. we show that p33 is a membrane-associated protein that is inserted into the membrane via a transmembrane helix formed by hydrophobic amino acid residues at the c-terminal end of the protein. removal of t ... | 2015 | 25880112 |
| development of salinity tolerance in rice by constitutive-overexpression of genes involved in the regulation of programmed cell death. | environmental factors contribute to over 70% of crop yield losses worldwide. of these drought and salinity are the most significant causes of crop yield reduction. rice is an important staple crop that feeds more than half of the world's population. however among the agronomically important cereals rice is the most sensitive to salinity. in the present study we show that exogenous expression of anti-apoptotic genes from diverse origins, atbag4 (arabidopsis), hsp70 (citrus tristeza virus) and p35 ... | 2015 | 25870602 |
| with a little help from my friends: complementation as a survival strategy for viruses in a long-lived host system. | in selective host species, the extent of citrus tristeza virus (ctv) infection is limited through the prevention of long-distance movement. as ctv infections often contain a population of multiple strains, we investigated whether the members of a population were capable of interaction, and what effect this would have on the infection process. we found that the tissue-tropism limitations of strain t36 in selective hosts could be overcome through interaction with a second strain, vt, increasing ti ... | 2015 | 25666523 |
| genetic diversity and evolution of two capsid protein genes of citrus tristeza virus isolates from china. | the genetic diversity and population structure of citrus tristeza virus (ctv) isolates from china were investigated based on partial sequences spanning the c-terminal end of p61 and the complete sequences of the cpm and cp genes. phylogenetic analysis revealed five known groups (rb, t30, t36, ha and vt) and one new group (vi) consisting of only chinese ctv isolates. incongruent phylogenetic trees coupled with recombination analysis suggested several recombination events in the cpm gene. positive ... | 2015 | 25387862 |
| the first identified citrus tristeza virus isolate of turkey contains a mixture of mild and severe strains. | the presence of citrus tristeza virus (ctv) has previously been reported in citrus growing regions of turkey. all serologically and biologically characterized isolates including iğdır, which was the first identified ctv isolates from turkey, were considered mild isolates. in this study, molecular characteristics of the iğdır isolate were determined by different methods. analysis of the iğdır isolate by western blot and bd-rt-pcr assays showed the presence of mca13 epitope, predominantly found in ... | 2013 | 25288926 |
| superinfection exclusion by citrus tristeza virus does not correlate with the production of viral small rnas. | superinfection exclusion (sie), a phenomenon in which a preexisting viral infection prevents a secondary infection with the same or closely related virus, has been described for different viruses, including important pathogens of humans, animals, and plants. several mechanisms acting at various stages of the viral life cycle have been proposed to explain sie. most cases of sie in plant virus systems were attributed to induction of rna silencing, a host defense mechanism that is mediated by small ... | 2014 | 25248160 |
| symptoms induced by transgenic expression of p23 from citrus tristeza virus in phloem-associated cells of mexican lime mimic virus infection without the aberrations accompanying constitutive expression. | citrus tristeza virus (ctv) is phloem restricted in natural citrus hosts. the 23-kda protein (p23) encoded by the virus is an rna silencing suppressor and a pathogenicity determinant. the expression of p23, or its n-terminal 157-amino-acid fragment comprising the zinc finger and flanking basic motifs, driven by the constitutive 35s promoter of cauliflower mosaic virus, induces ctv-like symptoms and other aberrations in transgenic citrus. to better define the role of p23 in ctv pathogenesis, we c ... | 2015 | 25171669 |
| protein-protein interactions between proteins of citrus tristeza virus isolates. | citrus tristeza virus (ctv) is one of the most devastating pathogens of citrus. its genome is organized into 12 open reading frames (orfs), of which ten orfs located at the 3'-terminus of the genome have multiple biological functions. the ten genes at the 3'-terminus of the genome of a severe isolate (ctv-s4) and three orfs (cp, cpm and p20) of three other isolates (n4, s45 and hb1) were cloned into pgbkt7 and pgadt7 yeast shuttle vectors. yeast two-hybridization (y2h) assays results revealed a ... | 2014 | 25064367 |
| a viral protein mediates superinfection exclusion at the whole-organism level but is not required for exclusion at the cellular level. | superinfection exclusion (sie), the ability of an established virus infection to interfere with a secondary infection by the same or a closely related virus, has been described for different viruses, including important pathogens of humans, animals, and plants. citrus tristeza virus (ctv), a positive-sense rna virus, represents a valuable model system for studying sie due to the existence of several phylogenetically distinct strains. furthermore, ctv allows sie to be examined at the whole-organi ... | 2014 | 25031351 |
| differential tropism in roots and shoots infected by citrus tristeza virus. | virus tropism is a result of interactions between virus, host and vector species, and determines the fate of an infection. in this study, we examined the infection process of citrus tristeza virus (ctv) in susceptible and resistant species, and found that the tropism of ctv is not simply phloem limited, but tissue specific. in resistant species, virus infection was not prevented, but mostly restricted to the roots. this phenomenon was also observed after partial replacement of genes of one ctv s ... | 2014 | 25010274 |
| characterization of a novel citrus tristeza virus genotype within three cross-protecting source gfms12 sub-isolates in south africa by means of illumina sequencing. | tristeza disease (caused by citrus tristeza virus, ctv) is currently controlled in south africa by means of cross-protection. in this study, we characterized the ctv populations of three grapefruit mild strain 12 (gfms12) single-aphid-transmission-derived sub-isolates at the whole-genome level using illumina sequencing technology. a novel south african isolate (ct-za3, of the t68 genotype) was shown to be the dominant genotype in all gfms12 sub-isolates tested, along with reads unique to various ... | 2014 | 24623089 |
| citrus tristeza virus-based rnai in citrus plants induces gene silencing in diaphorina citri, a phloem-sap sucking insect vector of citrus greening disease (huanglongbing). | a transient expression vector based on citrus tristeza virus (ctv) is unusually stable. because of its stability it is being considered for use in the field to control huanglongbing (hlb), which is caused by candidatus liberibacter asiaticus (clas) and vectored by asian citrus psyllid, diaphorina citri. in the absence of effective control strategies for clas, emphasis has been on control of d. citri. coincident cohabitation in phloem tissue by clas, d. citri and ctv was exploited to develop a no ... | 2014 | 24572372 |
| evidence of recombinant citrus tristeza virus isolate occurring in acid lime cv. pant lemon orchard in uttarakhand terai region of northern himalaya in india. | the present study for the first time describes biological and molecular characterization of citrus tristeza virus (ctv) occurring in the terai area of uttarakhand state in northern himalaya region of india. direct antigen coated-elisa and reverse transcriptase-polymerase chain reaction (rt-pcr) detected the ctv infection in acid lime cv. pant lemon (citrus aurantifolia) orchards of pantnagar with an estimated disease incidence of 16.6-20.5 %. to know the biological and genetic properties, an iso ... | 2013 | 24426255 |
| e-book on closteroviridae. | 2013 | 24409172 | |
| past and future of a century old citrus tristeza virus collection: a california citrus germplasm tale. | citrus tristeza virus (ctv) isolates collected from citrus germplasm, dooryard and field trees in california from 1914 have been maintained in planta under quarantine in the citrus clonal protection program (ccpp), riverside, california. this collection, therefore, represents populations of ctv isolates obtained over time and space in california. to determine ctv genetic diversity in this context, genotypes of ctv isolates from the ccpp collection were characterized using multiple molecular mark ... | 2013 | 24339822 |
| exploring the limits of vector construction based on citrus tristeza virus. | we examined the limits of manipulation of the citrus tristeza virus (ctv) genome for expressing foreign genes in plants. we previously created a vector with a foreign gene cassette inserted between the major and minor coat protein genes, which is position 6 from the 3' terminus. yet, this virus has 10 3'-genes with several other potential locations for expression of foreign genes. since genes positioned closer to the 3' terminus tend to be expressed in greater amounts, there were opportunities f ... | 2014 | 24314658 |
| the epitope structure of citrus tristeza virus coat protein mapped by recombinant proteins and monoclonal antibodies. | it has been known that there exists serological differentiation among citrus tristeza virus (ctv) isolates. the present study reports three linear epitopes (aa 48-63, 97-104, and 114-125) identified by using bacterially expressed truncated coat proteins and ten monoclonal antibodies against the native virions of ctv-s4. site-directed mutagenesis analysis demonstrated that the mutation d98g within the newly identified epitope (97)dddstgit(104) abolished its reaction to mabs 1, 4, and 10, and the ... | 2014 | 24314654 |
| virus-viroid interactions: citrus tristeza virus enhances the accumulation of citrus dwarfing viroid in mexican lime via virus-encoded silencing suppressors. | an assay to identify interactions between citrus dwarfing viroid (cdvd) and citrus tristeza virus (ctv) showed that viroid titer was enhanced by the coinfecting ctv in mexican lime but not in etrog citron. since ctv encodes three rna silencing suppressors (rsss), p23, p20 and p25, an assay using transgenic mexican limes expressing each rss revealed that p23 and, to a lesser extent, p25 recapitulated the effect observed with coinfections of ctv and cdvd. | 2014 | 24227850 |
| the rna-dependent rna polymerase of citrus tristeza virus forms oligomers. | the rna-dependent rna polymerases (rdrp) from citrus tristeza virus (ctv) were tagged with ha and flag epitopes. differentially tagged proteins were expressed either individually or concomitantly in escherichia coli. immunoprecipitation of the expressed proteins with anti-flag antibody followed by western blot with anti-ha antibody demonstrated that molecules of rdrp from ctv interact to form oligomers. yeast two-hybrid assays showed that molecules of rdrp interact in eukaryotic cells. co-immuno ... | 2013 | 24210106 |
| a localized linkage map of the citrus tristeza virus resistance gene region. | a localized genetic linkage map was developed of the region surrounding the citrus tristeza virus (ctv) resistance gene (designated ctv) from poncirus trifoliate l., a sexually compatible citrus relative. bulked segregant analysis (bsa) was used to identify potential resistance-associated rapd fragment markers in four intergeneric backcross families that were segregating for ctv resistance. eight rapd fragments were found that were consistently linked to ctv in the four families. map distances a ... | 1996 | 24166392 |
| mild strain cross protection of tristeza: a review of research to protect against decline on sour orange in florida. | tristeza, caused by citrus tristeza virus (ctv), has long been present in florida but outbreaks of decline on sour orange rootstock were occasional events until the late 1970s. sour orange rootstock was valued for the high quality of fruit produced and was widely used because of its tolerance of citrus blight, a disease of unknown etiology. research was directed towards the selection and screening of mild strains of ctv which could protect against sour orange decline strains. following the intro ... | 2013 | 24046764 |
| validation of high-throughput real time polymerase chain reaction assays for simultaneous detection of invasive citrus pathogens. | a number of important citrus pathogens are spread by graft propagation, arthropod vector transmission and inadvertent import and dissemination of infected plants. for these reasons, citrus disease management and clean stock programs require pathogen detection systems which are economical and sensitive to maintain a healthy industry. to this end, multiplex quantitative real-time pcr (qpcr) assays were developed allowing high-throughput and simultaneous detection of some major invasive citrus path ... | 2013 | 23891873 |
| a genetic system for citrus tristeza virus using the non-natural host nicotiana benthamiana: an update. | in nature citrus tristeza virus (ctv), genus closterovirus, infects only the phloem cells of species of citrus and related genera. finding that the ctv t36 strain replicated in nicotiana benthamiana (nb) protoplasts and produced normal virions allowed development of the first genetic system based on protoplast transfection with rna transcribed from a full-genome cdna clone, a laborious and uncertain system requiring several months for each experiment. we developed a more efficient system based o ... | 2013 | 23847598 |
| emergence and phylodynamics of citrus tristeza virus in sicily, italy. | citrus tristeza virus (ctv) outbreaks were detected in sicily island, italy for the first time in 2002. to gain insight into the evolutionary forces driving the emergence and phylogeography of these ctv populations, we determined and analyzed the nucleotide sequences of the p20 gene from 108 ctv isolates collected from 2002 to 2009. bayesian phylogenetic analysis revealed that mild and severe ctv isolates belonging to five different clades (lineages) were introduced in sicily in 2002. phylogeogr ... | 2013 | 23818960 |
| the defective rnas of closteroviridae. | the family closteroviridae consists of two genera, closterovirus and ampelovirus with monopartite genomes transmitted respectively by aphids and mealybugs and the crinivirus with bipartite genomes transmitted by whiteflies. the closteroviridae consists of more than 30 virus species, which differ considerably in their phytopathological significance. some, like beet yellows virus and citrus tristeza virus (ctv) were associated for many decades with their respective hosts, sugar beets and citrus. o ... | 2013 | 23734149 |
| citrus tristeza virus-host interactions. | citrus tristeza virus (ctv) is a phloem-limited virus whose natural host range is restricted to citrus and related species. although the virus has killed millions of trees, almost destroying whole industries, and continually limits production in many citrus growing areas, most isolates are mild or symptomless in most of their host range. there is little understanding of how the virus causes severe disease in some citrus and none in others. movement and distribution of ctv differs considerably fr ... | 2013 | 23717303 |
| citrus tristeza virus p23: a unique protein mediating key virus-host interactions. | the large rna genome of citrus tristeza virus (ctv; ca. 20 kb) contains 12 open reading frames, with the 3'-terminal one corresponding to a protein of 209 amino acids (p23) that is expressed from an abundant subgenomic rna. p23, an rna-binding protein with a putative zinc-finger domain and some basic motifs, is unique to ctv because no homologs have been found in other closteroviruses, including the type species of the genus beet yellows virus (despite both viruses having many homologous genes). ... | 2013 | 23653624 |
| prevalence of citrus tristeza virus in mandarin of sikkim himalayan region. | the assessment of citrus tristeza virus incidence in mandarin of sikkim, involving sampling techniques, was estimated by das-elisa. mandarin orchards had high ctv incidence (46.32%), however, differential prevalence with regard to age of plant and location was observed. the ctv prevalence was relatively high in older orchards (51.01%) than that of younger ones (40.80%). under all the plant age groups, south district had the highest ctv incidence (52.50%) and east district had the lowest (37.71%) ... | 2011 | 23637493 |
| citrus tristeza virus: evolution of complex and varied genotypic groups. | amongst the closteroviridae, citrus tristeza virus (ctv) is almost unique in possessing a number of distinct and characterized strains, isolates of which produce a wide range of phenotype combinations among its different hosts. there is little understanding to connect genotypes to phenotypes, and to complicate matters more, these genotypes are found throughout the world as members of mixed populations within a single host plant. there is essentially no understanding of how combinations of genoty ... | 2013 | 23630519 |
| the closterovirus-derived gene expression and rna interference vectors as tools for research and plant biotechnology. | important progress in understanding replication, interactions with host plants, and evolution of closteroviruses enabled engineering of several vectors for gene expression and virus-induced gene silencing. due to the broad host range of closteroviruses, these vectors expanded vector applicability to include important woody plants such as citrus and grapevine. furthermore, large closterovirus genomes offer genetic capacity and stability unrivaled by other plant viral vectors. these features provi ... | 2013 | 23596441 |
| developing an understanding of cross-protection by citrus tristeza virus. | citrus tristeza virus (ctv) causes two citrus diseases that have caused devastating losses in global citrus production. the first disease is quick decline of trees propagated on the sour orange rootstock. the second disease is stem pitting, which severely affects a number of economically important citrus varieties regardless of the rootstock used and results in reduced tree growth and vigor as well as in reduced fruit size and quality. both diseases continue to invade new areas. while quick decl ... | 2013 | 23577008 |
| citrus biotechnology: achievements, limitations and future directions. | citrus is one of the most important commercial and nutritional fruit crops in the world, hence it needs to be improved to cater to the diverse needs of consumers and crop breeders. genetic manipulation through conventional techniques in this genus is invariably a difficult task for plant breeders as it poses various biological limitations comprising long juvenile period, high heterozygosity, sexual incompatibility, nucellar polyembryony and large plant size that greatly hinder cultivar improveme ... | 2009 | 23572908 |
| citrus leaf blotch virus invades meristematic regions in nicotiana benthamiana and citrus. | to invade systemically host plants, viruses need to replicate in the infected cells, spread to neighbouring cells through plasmodesmata and move to distal parts of the plant via sieve tubes to start new infection foci. to monitor the infection of nicotiana benthamiana plants by citrus leaf blotch virus (clbv), leaves were agroinoculated with an infectious cdna clone of the clbv genomic rna expressing green fluorescent protein (gfp) under the transcriptional control of a duplicate promoter of the ... | 2013 | 23560714 |
| citrus tristeza virus p23: determinants for nucleolar localization and their influence on suppression of rna silencing and pathogenesis. | citrus tristeza virus (ctv) encodes a singular protein (p23, 209 amino acids) with multiple functions, including rna silencing suppression (rss). confocal laser-scanning microscopy of green fluorescent protein (gfp)-p23 agroexpressed in nicotiana benthamiana revealed its accumulation in the nucleolus, cajal bodies, and plasmodesmata. to dissect the nucleolar localization signal (nols) typically associated with basic motifs, seven truncated and 10 point-mutated versions of p23 were assayed. delet ... | 2013 | 23387469 |
| the genotypes of citrus tristeza virus isolates from china revealed by sequence analysis of multiple molecular markers. | the genotypes of ten citrus tristeza virus (ctv) isolates from central china were determined by examining multiple molecular markers (mmms) using 11 primer pairs. the results revealed that one isolate contained a single t30 genotype, two isolates contained a single vt genotype, and the other seven isolates were mixtures of two or more genotypes. sequence analysis of amplified mmms showed a high genetic diversity in chinese ctv populations. the genotypes resembling t36, rb and b165 were identifie ... | 2013 | 22987316 |
| genotype composition of populations of grapefruit-cross-protecting citrus tristeza virus strain gfms12 in different host plants and aphid-transmitted sub-isolates. | citrus tristeza virus (ctv) causes severe losses in grapefruit production in south africa and requires mild-strain cross-protection to maintain production. unfortunately, cross-protection breakdown of the pre-immunizing ctv grapefruit mild source gfms12 is prevalent in grapefruit in south africa. the ctv genotype composition of the gfms12 population inoculated onto different hosts was determined by sequencing part of orf1a and the p23 gene of multiple clones from each plant. analysis of the gfms ... | 2013 | 22932923 |
| high codon adaptation in citrus tristeza virus to its citrus host. | citrus tristeza virus (ctv), a member of the genus closterovirus within the family closteroviridae, is the causal agent of citrus tristeza disease. previous studies revealed that the negative selection, rna recombination and gene flow were the most important forces that drove ctv evolution. however, the ctv codon usage was not studied and thus its role in ctv evolution remains unknown. | 2012 | 22698086 |
| strategies for viral cross protection in plants. | viral cross protection in plants is known as an acquired immunity phenomenon, where a mild virus isolate/strain can protect plants against economic damage caused by a severe challenge strain/isolate of the same virus. mild strain cross protection (mscp) has been used extensively to control losses caused by a few major virus diseases in some parts of the world. so far, none of the many proposed mechanisms can fully explain the intact process of mscp. in fact, it may be that different mechanisms a ... | 2012 | 22678573 |
| enhancement or attenuation of disease by deletion of genes from citrus tristeza virus. | stem pitting is a common virus-induced disease of perennial woody plants induced by a range of different viruses. the phenotype results from sporadic areas of the stem in which normal xylem and phloem development is prevented during growth of stems. these alterations interfere with carbohydrate transport, resulting in reduced plant growth and yield. citrus tristeza virus (ctv), a phloem-limited closterovirus, induces economically important stem-pitting diseases of citrus. ctv has three nonconser ... | 2012 | 22593155 |
| distribution, genetic diversity and recombination analysis of citrus tristeza virus of india. | citrus tristeza virus (ctv) isolates representing all the citrus-growing geographical zones of india were analyzed for nucleotide sequence of the 5'orf1a fragments of the partial lproi domain and for the coat protein (cp) gene. the nucleotide sequences were compared with previously reported indian and ctv genotypes from genbank. the indian isolates had 80-99 % sequence identity for the 5'orf1a and 89-99 % identity for the cp genes. in phylogenetic tree analysis, all the indian and previously rep ... | 2012 | 22562224 |
| highly-sensitive and label-free indium phosphide biosensor for early phytopathogen diagnosis. | the development of highly-sensitive and label-free operating semiconductor-based, biomaterial detecting sensors has important applications in areas such as environmental science, biomedical research and medical diagnostics. in the present study, we developed an indium phosphide (inp) semiconductor-based resistive biosensor using the change of its electronic properties upon biomaterial adsorption as sensing element. to detect biomaterial at low concentrations, the procedure of functionalization a ... | 2013 | 22538056 |
| transformation of mexican lime with an intron-hairpin construct expressing untranslatable versions of the genes coding for the three silencing suppressors of citrus tristeza virus confers complete resistance to the virus. | citrus tristeza virus (ctv), the causal agent of the most devastating viral disease of citrus, has evolved three silencing suppressor proteins acting at intra- (p23 and p20) and/or intercellular level (p20 and p25) to overcome host antiviral defence. previously, we showed that mexican lime transformed with an intron-hairpin construct including part of the gene p23 and the adjacent 3' untranslated region displays partial resistance to ctv, with a fraction of the propagations from some transgenic ... | 2012 | 22405601 |
| superinfection exclusion is an active virus-controlled function that requires a specific viral protein. | superinfection exclusion, a phenomenon in which a preexisting viral infection prevents a secondary infection with the same or a closely related virus, has been described for various viruses, including important pathogens of humans, animals, and plants. the phenomenon was initially used to test the relatedness of plant viruses. subsequently, purposeful infection with a mild isolate has been implemented as a protective measure against virus isolates that cause severe disease. in the medical and ve ... | 2012 | 22398285 |
| characterization of isolates of citrus tristeza virus by sequential analyses of enzyme immunoassays and capillary electrophoresis-single-strand conformation polymorphisms. | citrus tristeza virus (ctv) is the causal agent of tristeza disease, which is one of the most devastating diseases of citrus crops worldwide. this paper describes a method for the rapid detection and genotyping of naturally spreading ctv isolates. this method uses elisa or dot-blot immunological tests to detect trees infected with ctv. the reaction wells or membrane spots for which there is a positive reaction are sequentially treated by (i) washing and elution of viral rna from the trapped samp ... | 2012 | 22305960 |
| complete genome sequence of mandarin decline citrus tristeza virus of the northeastern himalayan hill region of india: comparative analyses determine recombinant. | the complete genome sequence of a mandarin (citrus reticulata) decline ctv isolate, kpg3, of the darjeeling hills of the northeastern himalayan region of india is reported for the first time. the complete kpg3 genome has 19253 nt, and its nucleotide sequence identity ranged from 79% with the florida ctv isolate t36 to 94% with the israel isolate vt, whereas its identity to b165, the other indian isolate, was 89%. phylogenetic analysis indicated that the kpg3 genome is closely related to isolate ... | 2011 | 22160128 |
| Characterizing the citrus cultivar Carrizo genome through 454 shotgun sequencing. | The citrus cultivar Carrizo is the single most important rootstock to the US citrus industry and has resistance or tolerance to a number of major citrus diseases, including citrus tristeza virus, foot rot, and Huanglongbing (HLB, citrus greening). A Carrizo genomic sequence database providing approximately 3.5× genome coverage (haploid genome size approximately 367 Mb) was populated through 454 GS FLX shotgun sequencing. Analysis of the repetitive DNA fraction indicated a total interspersed repe ... | 2011 | 22133378 |
| The evolutionary rate of Citrus tristeza virus ranks among the rates of the slowest RNA viruses. | Citrus tristeza virus (CTV) has been intensively studied at the molecular level. However, knowledge regarding the dynamics of its evolution is practically non-existent. In the past diverse authors have referred to CTV as a highly variable virus implying a quick evolution. Others have, in recent times referred to CTV as an exceptionally slow evolving virus. In this work, we used the coat protein (CP) gene to estimate the rate of evolution. This was obtained from a large set of heterochronous CP ... | 2011 | 22071513 |
| a personal history of virus-based vector construction. | the ability to express foreign genes or to silence endogenous genes in plants has revolutionized both basic and applied plant biology. virus-based expression systems, in which the foreign mrna is greatly amplified by virus replication, can produce very high levels of proteins or peptides in leaves and other tissues. vectors have been available for about 25 years. they are commonplace as laboratory tools, but their initial commercial expectations have not been met for numerous reasons. yet, appli ... | 2011 | 22025032 |
| top 10 plant viruses in molecular plant pathology. | many scientists, if not all, feel that their particular plant virus should appear in any list of the most important plant viruses. however, to our knowledge, no such list exists. the aim of this review was to survey all plant virologists with an association with molecular plant pathology and ask them to nominate which plant viruses they would place in a 'top 10' based on scientific/economic importance. the survey generated more than 250 votes from the international community, and allowed the gen ... | 2011 | 22017770 |
| a plant virus evolved by acquiring multiple nonconserved genes to extend its host range. | viruses have evolved as combinations of genes whose products interact with cellular components to produce progeny virus throughout the plants. some viral genes, particularly those that are involved in replication and assembly, tend to be relatively conserved, whereas other genes that have evolved for interactions with the specific host for movement and to counter host-defense systems tend to be less conserved. closteroviridae encode 1-5 nonconserved orfs. citrus tristeza virus (ctv), a closterov ... | 2011 | 21987809 |
| Agroinoculation of Citrus tristeza virus causes systemic infection and symptoms in the presumed nonhost Nicotiana benthamiana. | Citrus tristeza virus (CTV) naturally infects only some citrus species and relatives and within these it only invades phloem tissues. Failure to agroinfect citrus plants and the lack of an experimental herbaceous host hindered development of a workable genetic system. A full-genome cDNA of CTV isolate T36 was cloned in binary plasmids and was used to agroinfiltrate Nicotiana benthamiana leaves, with or without coinfiltration with plasmids expressing different silencing-suppressor proteins. A tim ... | 2011 | 21899435 |
| calculation of diagnostic parameters of advanced serological and molecular tissue-print methods for detection of citrus tristeza virus: a model for other plant pathogens. | citrus tristeza virus (ctv) is one of the most important virus diseases that affect citrus. control of ctv is achieved by grafting selected virus-free citrus scions onto ctv-tolerant or -resistant rootstocks. quarantine and certification programs are essential for avoiding the entry and propagation of severe strains of ctv. citrus nurseries in spain and central california (united states) maintain zero-tolerance policies for ctv that require sensitive, specific, and reliable pathogen-detection me ... | 2012 | 21879789 |
| ectopic expression of the p23 silencing suppressor of citrus tristeza virus differentially modifies viral accumulation and tropism in two transgenic woody hosts. | citrus tristeza virus (ctv), a phloem-restricted closterovirus infecting citrus, encodes three different silencing suppressors (p25, p20 and p23), one of which (p23) is a pathogenicity determinant that induces aberrations resembling ctv symptoms when expressed ectopically in transgenic citrus hosts. in this article, the effect of p23 ectopic expression on virus infection was examined in sweet orange (swo), a highly susceptible host, and sour orange (so), which severely restricts ctv cell-to-cell ... | 2011 | 21726389 |
| citrus tristeza virus infection induces the accumulation of viral small rnas (21-24-nt) mapping preferentially at the 3'-terminal region of the genomic rna and affects the host small rna profile. | to get an insight into the host rna silencing defense induced by citrus tristeza virus (ctv) and into the counter defensive reaction mediated by its three silencing suppressors (p25, p20 and p23), we have examined by deep sequencing (solexa-illumina) the small rnas (srnas) in three virus-host combinations. our data show that ctv srnas: (i) represent more than 50% of the total srnas in mexican lime and sweet orange (where ctv reaches relatively high titers), but only 3.5% in sour orange (where th ... | 2011 | 21327514 |
| a sensitive and reliable rt-nested pcr assay for detection of citrus tristeza virus from naturally infected citrus plants. | a specific and sensitive reverse transcriptase-nested polymerase chain reaction assay (rt-npcr) was developed for the detection of citrus tristeza virus (ctv) from naturally infected citrus samples. two sets of primer pairs were designed by alignment of nucleotide sequences available in genbank database for different genotypes of ctv. rt-npcr reaction components and thermal cycling parameters were optimized and reaction conditions were standardized. sequencing of the pcr products from direct and ... | 2011 | 21298268 |
| somatic hybridization for citrus rootstock breeding: an effective tool to solve some important issues of the mediterranean citrus industry. | the prevalence of sour orange rootstock in the southern and eastern part of the mediterranean basin is presently threatened by the spread of citrus tristeza virus (ctv) and its main vector toxoptera citricida, combined with abiotic constraints such as drought, salinity and alkalinity. the search for alternative ctv-resistant rootstocks that also withstand the other constraints is now considered an urgent priority for a sustainable citrus industry in the area. complementary progenitors can be fou ... | 2011 | 21225429 |
| development and application of a multiplex reverse-transcription polymerase chain reaction assay for screening a global collection of citrus tristeza virus isolates. | the emerging diversity of citrus tristeza virus (ctv) genotypes has complicated detection and diagnostic measures and prompted the search for new differentiation methods. to simplify the identification and differentiation of ctv genotypes, a multiplex reverse-transcription polymerase chain reaction (rt-pcr) technique for the screening of ctv isolates was developed. variable regions within the open reading frame (orf)-1a of diverse ctv genotypes were identified to develop first a simplex (s) and ... | 2010 | 20839943 |
| transgenic citrus plants expressing the citrus tristeza virus p23 protein exhibit viral-like symptoms. | summary the 23 kda protein (p23) coded by the 3'-terminal gene of citrus tristeza virus (ctv), a member of the genus closterovirus with the largest genome among plant rna viruses, is an rna-binding protein that contains a motif rich in cysteine and histidine residues in the core of a putative zinc-finger domain. on this basis, a regulatory role for ctv replication or gene expression has been suggested for p23. to explore whether over-expression of this protein in transgenic plants could affect t ... | 2001 | 20572989 |
| an atypical 3'-controller element mediates low-level transcription of the p6 subgenomic mrna of citrus tristeza virus. | summary citrus tristeza virus (ctv) has within the 3'-half of the genome ten open reading frames (orfs) that are expressed through a series of 3'-coterminal subgenomic (sg) messenger (m)rnas that, in general, function as monocistronic mrnas with only the 5'-most orf translated. yet only nine sg mrnas have been detected, suggesting that orf 3, which is predicted to encode a small hydrophobic protein of approximately 6 kda (p6), might be expressed in some other manner, perhaps from a functionally ... | 2005 | 20565647 |
| comparison of ftir spectra between huanglongbing (citrus greening) and other citrus maladies. | fourier transform infrared (ftir) spectroscopy has the ability to quickly identify the presence of specific carbohydrates in plant materials. the presence of the disease huanglongbing (hlb) in the leaves of infected citrus plants has a distinctive spectrum that can be used to distinguish an infected plant from a healthy plant. however, many citrus diseases display similar visible symptoms and are of concern to citrus growers. in this study several citrus diseases (citrus leaf rugose virus, citru ... | 2010 | 20438136 |
| molecular characterization of citrus tristeza virus isolates from the northeastern himalayan region of india. | citrus tristeza virus (ctv) isolates from the darjeeling hills of the northeastern himalayan region of india were characterized by biological indexing, multiple molecular marker (mmm) analysis, heteroduplex mobility assay (hma) and sequence analysis. variability was studied using the cp gene and a 5' orf1a fragment of the ctv genome. hma and sequence analysis of the 5' orf1a fragment classified darjeeling isolates into two groups, whereas cp gene analysis provided evidence for three different gr ... | 2010 | 20437063 |
| heterologous minor coat proteins of citrus tristeza virus strains affect encapsidation, but the coexpression of hsp70h and p61 restores encapsidation to wild-type levels. | the long flexuous bipolar virions of citrus tristeza virus (ctv), a closterovirus, are encapsidated with two capsid proteins at opposite ends: the minor coat protein (cpm) encapsidates the 5' 630 nts of the genomic rna and the major coat protein encapsidates the remainder of the genome. in this study, we found encapsidation of ctv cpm in the absence of other assembly-related proteins is highly specific in contrast to most plant viruses that allow virion assembly by a range of heterologous coat p ... | 2010 | 20399478 |
| genome analysis of an orange stem pitting citrus tristeza virus isolate reveals a novel recombinant genotype. | an orange stem pitting citrus tristeza virus (ctv) isolate ctv-b165 was found to be symptomatically similar to other known ctv-vt isolates however molecular methods failed to classify it as an identifiable ctv genotype. the sequence variation of the indian ctv-b165 isolate was compared to the three well known ctv genotypes, t36, t30, and vt. the genome of the predominant component of ctv-b165 was 19,247 nt in length with 12 open reading frames (orfs) and was structurally identical to the other c ... | 2010 | 20381550 |
| isolates of citrus tristeza virus that overcome poncirus trifoliata resistance comprise a novel strain. | the economically important rootstock species poncirus trifoliata is resistant to most isolates of citrus tristeza virus (ctv), but not to members of the ctv resistance-breaking (rb) strain presently found in new zealand. in this study, five known and suspected rb isolates were separated from field mixtures, and their genomes were sequenced in full. it was found that the rb isolates are members of a single phylogenetically distinct clade with an average of 90.3% genomic nucleotide sequence identi ... | 2010 | 20352212 |
| rapid differentiation and identification of potential severe strains of citrus tristeza virus by real-time reverse transcription-polymerase chain reaction assays. | a multiplex taqman-based real-time reverse transcription (rt) polymerase chain reaction (pcr) assay was developed to identify potential severe strains of citrus tristeza virus (ctv) and separate genotypes that react with the monoclonal antibody mca13. three strain-specific probes were developed using intergene sequences between the major and minor coat protein genes (cpi) in a multiplex reaction. probe cpi-vt3 was designed for vt and t3 genotypes; probe cpi-t36 for t36 genotypes; and probe cpi-t ... | 2010 | 20205535 |
| transgenic expression in citrus of single-chain antibody fragments specific to citrus tristeza virus confers virus resistance. | citrus tristeza virus (ctv) causes one of the most destructive viral diseases of citrus worldwide. generation of resistant citrus genotypes through genetic engineering could be a good alternative to control ctv. to study whether production of single-chain variable fragment (scfv) antibodies in citrus could interfere and immunomodulate ctv infection, transgenic mexican lime plants expressing two different scfv constructs, separately and simultaneously, were generated. these constructs derived fro ... | 2010 | 20204695 |
| the pathogenicity determinant of citrus tristeza virus causing the seedling yellows syndrome maps at the 3'-terminal region of the viral genome. | citrus tristeza virus (ctv) (genus closterovirus, family closteroviridae) causes some of the more important viral diseases of citrus worldwide. the ability to map disease-inducing determinants of ctv is needed to develop better diagnostic and disease control procedures. a distinctive phenotype of some isolates of ctv is the ability to induce seedling yellows (sy) in sour orange, lemon and grapefruit seedlings. in florida, the decline isolate of ctv, t36, induces sy, whereas a widely distributed ... | 2010 | 20078776 |