| whiteflies (bemisia tabaci) issued from eggs bombarded with infectious dna clones of tomato yellow leaf curl virus from israel (tylcv) are able to infect tomato plants. | we have reported previously that tomato yellow leaf curl virus from israel (tylcv) penetrates the reproductive system of its vector, the whitefly bemisia tabaci biotype b, and may be transmitted to progeny. in order to mimic this phenomenon and to understand how tylcv accompanies the development of the insect, we have bombarded b. tabaci eggs with an infectious dna clone of tylcv. after a linear full-length genomic copy of tylcv dna was delivered to eggs, the dpni-sensitive dna became circular a ... | 2002 | 12038688 |
| a natural recombinant between the geminiviruses tomato yellow leaf curl sardinia virus and tomato yellow leaf curl virus exhibits a novel pathogenic phenotype and is becoming prevalent in spanish populations. | this work provides evidence of the significant contribution of recombination to the genetic diversification of emerging begomovirus populations. in southern spain, tomato yellow leaf curl sardinia virus (tylcsv) and tomato yellow leaf curl virus (tylcv) are distinct geminivirus species that coexist in the field and contribute to the tomato yellow leaf curl disease epidemic. a natural recombinant between tylcsv and tylcv has been detected and an infectious clone of a recombinant isolate (es421/99 ... | 2002 | 12490393 |
| dual interaction of plant pcna with geminivirus replication accessory protein (ren) and viral replication protein (rep). | geminiviruses replicate their small, single-stranded dna genomes in plant nuclei using host replication machinery. similar to most dicotyledonous plant-infecting geminiviruses, tomato yellow leaf curl sardinia virus (tylcsv) encodes a protein, ren, that enhances viral dna accumulation through an unknown mechanism. earlier studies showed that ren protein from another geminivirus, tomato golden mosaic virus (tgmv), forms oligomers and interacts with rep protein, the only viral protein essential fo ... | 2003 | 12919743 |
| interaction between a geminivirus replication protein and the plant sumoylation system. | geminiviruses are small dna viruses that replicate in nuclei of infected plant cells after accumulation of host replication machinery. tomato golden mosaic virus (tgmv) and tomato yellow leaf curl sardinia virus (tylcsv) encode a protein, repac1 (or rep), that is essential for viral replication. rep/repac1 is an oligomeric protein that binds to double-stranded dna, catalyzes cleavage and ligation of single-stranded dna, and is sufficient for host induction. it also interacts with several host pr ... | 2004 | 14990696 |
| tylcsv dna, but not infectivity, can be transovarially inherited by the progeny of the whitefly vector bemisia tabaci (gennadius). | the transovarial transmission of two species of begomovirus, tomato yellow leaf curl virus (tylcv) and tomato yellow leaf curl sardinia virus (tylcsv), through generations of bemisia tabaci of the b and q biotypes has been investigated. different life stages of the progeny of viruliferous female whiteflies have been analysed by pcr detection of viral dna and infectivity tests. our results indicate that tylcsv dna can be detected in eggs and nymphs, and to a lesser extent adults, of the first-gen ... | 2004 | 15193923 |
| tête à tête of tomato yellow leaf curl virus and tomato yellow leaf curl sardinia virus in single nuclei. | since 1997 two distinct geminivirus species, tomato yellow leaf curl sardinia virus (tylcsv) and tomato yellow leaf curl virus (tylcv), have caused a similar yellow leaf curl disease in tomato, coexisted in the fields of southern spain, and very frequently doubly infected single plants. tomatoes as well as experimental test plants (e.g., nicotiana benthamiana) showed enhanced symptoms upon mixed infections under greenhouse conditions. viral dna accumulated to a similar extent in singly and doubl ... | 2004 | 15367638 |
| severe outbreaks of tomato yellow leaf curl sardinia virus in calabria, southern italy. | during the winter 2003--2004 a serious disease was observed in protected tomato crops in castrovillari, reggio calabria province, southern italy. symptoms consisted in marginal leaf yellowing, leaf curling, plant stunting, flower abortion. the disease was detected in a group of greenhouses (about 10ha) where several tomato cultivars were grown hydroponically. the highest incidence of infection (60-100%) was observed in tomatoes grafted on beaufort drs tomato rootstock. since the symptoms were si ... | 2004 | 15756842 |
| single-stranded dna of tomato leaf curl virus accumulates in the cytoplasm of phloem cells. | geminiviruses have been reported to replicate in, and localize to, the nuclei of host plant cells. we have investigated the tissue and intracellular distribution of the monopartite tomato leaf curl virus (tlcv) by in situ hybridization. contrary to the current understanding of geminiviral localization, single-stranded (ss) dna of tlcv accumulated in the cytoplasm. tlcv ssdna was also found in the nucleus, as was lower levels of replicative form double-stranded (ds) dna. under the same conditions ... | 2006 | 16457866 |
| begomovirus genetic diversity in the native plant reservoir solanum nigrum: evidence for the presence of a new virus species of recombinant nature. | we examined the native plant host solanum nigrum as reservoir of genetic diversity of begomoviruses that cause the tomato yellow leaf curl disease (tylcd) emerging in southern spain. presence of isolates of all the species and strains found associated with tylcd in this area was demonstrated. mixed infections were common, which is a prerequisite for recombination to occur. in fact, presence of a novel recombinant begomovirus was demonstrated. analysis of an infectious clone showed that it result ... | 2006 | 16580040 |
| post-transcriptional gene silencing in controlling viruses of the tomato yellow leaf curl virus complex. | tomato yellow leaf curl disease (tylcd) is caused by a group of geminiviruses that belong to the tomato yellow leaf curl virus (tylcv) complex and are transmitted by the whitefly (bemisia tabaci genn.). the disease causes great yield losses in many countries throughout the mediterranean region and the middle east. in this study, the efficacy of post-transcriptional gene silencing (ptgs) to control the disease caused by tylcv complex was investigated. non-coding conserved regions from the genome ... | 2006 | 16862387 |
| dna helicase activity is associated with the replication initiator protein rep of tomato yellow leaf curl geminivirus. | the rep protein of tomato yellow leaf curl sardinia virus (tylcsv), a single-stranded dna virus of plants, is the replication initiator essential for virus replication. tylcsv rep has been classified among atpases associated with various cellular activities (aaa+ atpases), in superfamily 3 of small dna and rna virus replication initiators whose paradigmatic member is simian virus 40 large t antigen. members of this family are dna- or rna-dependent atpases with helicase activity necessary for vir ... | 2006 | 16943286 |
| founder effect, plant host, and recombination shape the emergent population of begomoviruses that cause the tomato yellow leaf curl disease in the mediterranean basin. | tomato yellow leaf curl disease (tylcd)-associated viruses present a highly structured population in the western mediterranean basin, depending on host, geographical region and time. about 1,900 tomato and common bean samples were analyzed from which 111 isolates were characterized genetically based on a genome sequence that comprises coding and non-coding regions. isolates of three distinct begomoviruses previously described were found (tomato yellow leaf curl virus, tylcv, tomato yellow leaf c ... | 2007 | 17070885 |
| solution structure, divalent metal and dna binding of the endonuclease domain from the replication initiation protein from porcine circovirus 2. | circoviruses are the smallest circular single-stranded dna viruses able to replicate in mammalian cells. essential to their replication is the replication initiator, or rep protein that initiates the rolling circle replication (rcr) of the viral genome. here we report the nmr solution three-dimensional structure of the endonuclease domain from the rep protein of porcine circovirus type 2 (pcv2), the causative agent of postweaning multisystemic wasting syndrome in swine. the domain comprises resi ... | 2007 | 17275023 |
| typing of tomato yellow leaf curl viruses and their vector in italy. | a molecular survey of tylcv/tylcsv and their associated vector bemisia tabaci, was performed during 2004-2005 in five regions of southern italy: i.e. sardinia (one locations), sicily (one location), calabria (three locations), campania (two locations) and basilicata (one location). a total of 71 tomato samples were checked for virus infection and for the presence of the vector. degenerate primers allowing the amplification of the coat protein gene of both tylcsv and tylcv isolates were designed. ... | 2006 | 17390884 |
| integrated management of tylcv/tylcsv on greenhouse hydroponic tomatoes in southern italy. | tomato yellow leaf curl (tylc) caused by tomato yellow leaf curl virus (tylcv) and tomato yellow leaf curl sardinia virus (tylcsv), vectored by the whitefly bemisia tabaci, is a major disease of tomato in sardinia and sicily, and is becoming a serious threat in southern italy too. tylcsv was first reported in calabria region in 1991, but apparently it was an occasional outbreak, and b. tabaci was not detected. later, during the 2003-2004 winter, a serious epidemic was observed in protected tomat ... | 2006 | 17390886 |
| frequent occurrence of recombinants in mixed infections of tomato yellow leaf curl disease-associated begomoviruses. | begomoviruses are plant dna viruses for which recombination plays a key role in driving evolution. however, little is known about how frequently begomovirus recombinants arise in mixed infected plants. to tackle this issue, co-infections of tomato with monopartite begomoviruses associated with the tomato yellow leaf curl disease, tomato yellow leaf curl sardinia virus and tomato yellow leaf curl virus, have been studied as a model system. the frequency of recombinant genotypes in the progeny pop ... | 2007 | 17467025 |
| solution structure of the endonuclease domain from the master replication initiator protein of the nanovirus faba bean necrotic yellows virus and comparison with the corresponding geminivirus and circovirus structures. | nanoviruses are a family of plant viruses that possess a genome of multiple circular single-stranded dna (ssdna) components and are strikingly similar in their replication mode to the plant geminiviruses and to the circoviruses that infect birds or mammals. these viruses multiply by rolling circle replication using virus-encoded multifunctional replication initiator proteins (rep proteins) that catalyze the initiation of replication on a double-stranded dna (dsdna) intermediate and the resolutio ... | 2007 | 17472345 |
| genetic structure and evolution of natural populations of viruses causing the tomato yellow leaf curl disease in spain. | the population structure and genetic variation of two begomoviruses: tomato yellow leaf curl sardinia virus (tylcsv) and tomato yellow leaf curl virus (tylcv) in tomato crops of spain were studied from 1997 until 2001. restriction digestion of a genomic region comprised of the cp coat protein gene (cpr) of 358 tylc virus isolates enabled us to classify them into 14 haplotypes. nucleotide sequences of two genomic regions: cpr, and the surrounding intergenic region (sir) were determined for at lea ... | 2007 | 17524509 |
| a single-tube pcr assay for detecting viruses and their recombinants that cause tomato yellow leaf curl disease in the mediterranean basin. | tomato yellow leaf curl disease (tylcd) is well known in mediterranean countries, where it has been causing severe losses in tomato crops for decades. until recently, two viruses (with several isolates) in the genus begomovirus, family geminiviridae, have been associated with the epidemics: tomato yellow leaf curl virus (tylcv) and tomato yellow leaf curl sardinia virus (tylcsv). however, recombinants between these, such as tomato yellow leaf curl malaga virus (tylcmalv), are spreading, and new ... | 2008 | 17868911 |
| three years survey of tomato yellow leaf curl sardinia virus reservoir weed hosts in southern italy. | during the period from august 2004 to june 2006 a serious tomato yellow leaf curl epidemic caused by both tomato yellow leaf curl sardinia virus (tylcsv) and tomato yellow leaf curl virus (tylcs) was observed in protected tomato crops in castrovillari, calabria region, in a group of greenhouses where tomato is grown hydroponically. a three years survey for reservoir weed hosts of these viruses was performed during summer period in order to identify where the viruses persist during the host-free ... | 2007 | 18396845 |
| pepper (capsicum annuum) is a dead-end host for tomato yellow leaf curl virus. | abstract tomato yellow leaf curl (tylc) is one of the most devastating pathogens affecting tomato (lycopersicon esculentum) worldwide. the disease is caused by a complex of begomovirus species, two of which, tomato yellow leaf curl sardinia virus (tylcsv) and tomato yellow leaf curl virus (tylcv), are responsible for epidemics in southern spain. tylcv also has been reported to cause severe damage to common bean (phaseolus vulgaris) crops. pepper (capsicum annuum) plants collected from commercial ... | 2005 | 18943307 |
| sequence analysis and classification of apparent recombinant begomoviruses infecting tomato in the nile and mediterranean basins. | abstract numerous whitefly-transmitted viral diseases of tomato have emerged in countries around the nile and mediterranean basins the last 20 years. these diseases are caused by monopartite geminiviruses (family gemini viridae) belonging to the genus begomovirus that probably resulted from numerous recombination events. the molecular biodiversity of these viruses was investigated to better appreciate the role and importance of recombination and to better clarify the phylogenetic relationships a ... | 2005 | 18943321 |
| evaluation of two gene-silencing constructs for resistance to tomato yellow leaf curl viruses in nicotiana benthamiana plants. | infiltration of agrobacterium tumefaciens into intact plant leaves of n. benthamiana was used to test the efficiency of two virus-based silencing constructs conferring resistance to the closely related begomoviruses. the constructs contained the most conserved sequences of the coat protein (cp) gene and replication-associated protein (rep) gene of tomato yellow leaf curl sardinia virus (sicily strain) (tylcsv-[sic]). both constructs formed a hairpin structure that enhanced the post-transcription ... | 2008 | 18999888 |
| first record of tomato yellow leaf curl sardinia virus (tylcsv) on pepper in italy. | during a survey in summer 2007, a disease of pepper (capsicum annuum) under plastic tunnels was observed in policoro (matera), on the ionic coast of basilicata region, with a disease incidence in some cases of more than 50%. affected cultivars were eppo and almund (s et g). the diseased plants exhibited light mosaic or mottling, leaf distortion, interveinal and marginal leaf chlorosis, upward curling of leaf margins of older leaves. the causal pathogen was suspected to be a begomovirus due to th ... | 2008 | 19226766 |
| two new natural begomovirus recombinants associated with the tomato yellow leaf curl disease co-exist with parental viruses in tomato epidemics in italy. | two tomato geminivirus species co-exist in protected crops in sicily, tomato yellow leaf curl sardinia virus (tylcsv, found in 1989) and tomato yellow leaf curl virus (tylcv, found in 2002), and mixed infections have been detected. in a field survey conducted in 2004, the viral intergenic region (ir) was amplified from infected plants, and molecules apparently hybrid between the two species were found, but only in plants where one or both parental species were also present. two of these hybrids, ... | 2009 | 19463717 |
| use of tomato leaf curl virus (tylcv) truncated rep gene sequence to engineer tylcv resistance in tomato plants. | tomato yellow leaf curl disease causes severe losses in tomato production throughout mediterranean countries including tunisia. in order to generate engineered resistance to this disease, an intron-hairpin rna construct harboring a tomato yellow leaf curl sardinia virus (tylcsv) truncated replication-associated protein (rep) gene was used to transform genotype of tomato plants. prepared transgenic plants were agro-inoculated with tunisian infectious strain of tylcsv and screened for the resistan ... | 2009 | 19537910 |
| begomovirus coat protein interacts with a small heat-shock protein of its transmission vector (bemisia tabaci). | tomato yellow leaf curl sardinia virus (tylcsv) is transmitted from plant to plant by the whitefly bemisia tabaci in a persistent-circulative manner. the coat protein (cp) plays an important role in this transmission cycle. in this study, the cp was used to screen a bemisia tabaci cdna library using the yeast two-hybrid system, in a search for interacting partners. a member of the small heat-shock protein family (termed bthsp16) was identified and its interaction with the cp was verified by an i ... | 2009 | 19817909 |
| differentiation of tomato yellow leaf curl virus and tomato yellow leaf curl sardinia virus using real-time taqman pcr. | during the past four decades, tomato yellow leaf curl disease has become one of the major constraints in tomato production worldwide. in the mediterranean basin, several isolates from two major begomovirus species are involved in outbreaks and persistent epidemics. a real-time taqman pcr assay was developed and evaluated for the rapid and multiplex detection and differentiation of two begomoviruses often found in mixed infections in the region, tomato yellow leaf curl virus (tylcv) and tomato ye ... | 2010 | 20153376 |
| an epidemiological survey of tylcd in southern sardinia (italy). | tomato yellow leaf curl sardinia virus (tylcsv) and tomato yellow leaf curl virus (tylcv) are among the most virulent pathogens of greenhouse tomatoes in sardinia (italy). to investigate the relationship between seasonal population trends of the vector bemisia tabaci and the dynamics of tylcd spread to susceptible crops, between may and october 2007 we carried out a survey in a tomato growing area located in the south of the island. on three farms specialized in the production of fresh market to ... | 2009 | 20222569 |
| severe outbreak of tomato yellow leaf curl sardinia virus on pepper in southern italy. | during summer and autumn 2008 a severe outbreak of pepper leaf curl disease (plcd) was observed in pepper crops under plastic tunnels in the ionic coast of basilicata region. its incidence reached, in some cases, values close to 50%. the beginning of infections was recorded along the perimeter of the tunnels, where it reached a percentage of almost 100%. the infection then progressively spread towards the central areas of the greenhouses. large populations of whiteflies, identificated as bemisia ... | 2009 | 20222578 |
| oligonucleotide microarray-based detection and identification of 10 major tomato viruses. | a dna microarray chip was developed for screening 10 major economically important tomato viruses from infected plants using "combimatrix" platform 40-mer oligonucleotide probes. a total of 279 oligonucleotide virus probes were specific for simultaneous multiple detection, identification, differentiation and/or genotyping of each of the following tomato rna viruses and/or strains and a virus satellite: cucumber mosaic virus, cucumber mosaic virus satellite rna, tomatoinfectiouschlorosisvirus, tom ... | 2010 | 20470828 |
| tomato yellow leaf curl viruses: ménage à trois between the virus complex, the plant and the whitefly vector. | tomato yellow leaf curl disease (tylcd) is one of the most devastating viral diseases affecting tomato crops in tropical, subtropical and temperate regions of the world. here, we focus on the interactions through recombination between the different begomovirus species causing tylcd, provide an overview of the interactions with the cellular genes involved in viral replication, and highlight recent progress on the relationships between these viruses and their vector, the whitefly bemisia tabaci. t ... | 2010 | 20618703 |
| rna viruses and their silencing suppressors boost abutilon mosaic virus, but not the old world tomato yellow leaf curl sardinia virus. | mixed viral infections can induce different changes in symptom development, genome accumulation and tissue tropism. these issues were investigated for two phloem-limited begomoviruses, abutilon mosaic virus (abmv) and tomato yellow leaf curl sardinia virus (tylcsv) in nicotiana benthamiana plants doubly infected by either the potyvirus cowpea aphid-borne mosaic virus (cabmv) or the tombusvirus artichoke mottled crinkle virus (amcv). both rna viruses induced an increase of the amount of abmv, led ... | 2011 | 21843560 |
| conformation-selective methylation of geminiviral dna. | geminiviruses with small circular single-stranded dna genomes replicate in plant cell nuclei using various double-stranded dna intermediates: distinct open circular and covalently closed circular as well as heterogeneous linear dna. their dna may be methylated partially at cytosine residues, which has been detected previously by bisulfite sequencing and subsequent polymerase chain reaction. in order to determine the methylation patterns of the circular molecules, the dna of tomato yellow leaf cu ... | 2011 | 21835804 |
| identification of host genes involved in geminivirus infection using a reverse genetics approach. | geminiviruses, like all viruses, rely on the host cell machinery to establish a successful infection, but the identity and function of these required host proteins remain largely unknown. tomato yellow leaf curl sardinia virus (tylcsv), a monopartite geminivirus, is one of the causal agents of the devastating tomato yellow leaf curl disease (tylcd). the transgenic 2irgfp n. benthamiana plants, used in combination with virus induced gene silencing (vigs), entail an important potential as a tool i ... | 2011 | 21818318 |
| the c2 protein from the geminivirus tomato yellow leaf curl sardinia virus decreases sensitivity to jasmonates and suppresses jasmonate-mediated defences. | an increasing body of evidence points at a role of the plant hormones jasmonates (jas) in determining the outcome of plant-virus interactions. geminiviruses, small dna viruses infecting a wide range of plant species worldwide, encode a multifunctional protein, c2, which is essential for full pathogenicity. the c2 protein has been shown to suppress the ja response, although the current view on the extent of this effect and the underlying molecular mechanisms is incomplete. in this work, we use a ... | 2016 | 27135228 |
| transgenically expressed t-rep of tomato yellow leaf curl sardinia virus acts as a trans-dominant-negative mutant, inhibiting viral transcription and replication. | we have previously shown that transgenic expression of a truncated c1 gene of tomato yellow leaf curl sardinia virus (tylcsv), expressing the first 210 amino acids of the replication-associated protein (t-rep) and potentially coexpressing the c4 protein, confers resistance to the homologous virus in nicotiana benthamiana plants. in the present study we have investigated the role of t-rep and c4 proteins in the resistance mechanism, analyzing changes in virus transcription and replication. transg ... | 2001 | 11602699 |
| tomato yellow leaf curl sardinia virus rep-derived resistance to homologous and heterologous geminiviruses occurs by different mechanisms and is overcome if virus-mediated transgene silencing is activated. | the replication-associated protein (rep) of geminiviruses is involved in several biological processes brought about by the presence of distinct functional domains. recently, we have exploited the multifunctional character of the tomato yellow leaf curl sardinia virus (tylcsv) rep to develop a molecular interference strategy to impair tylcsv infection. we showed that transgenic expression of its n-terminal 210 amino acids (rep-210) confers resistance to the homologous virus by inhibiting viral tr ... | 2003 | 12767999 |
| a versatile transreplication-based system to identify cellular proteins involved in geminivirus replication. | a versatile green fluorescent protein (gfp) expression cassette containing the replication origins of the monopartite begomovirus tomato yellow leaf curl sardinia virus (tylcsv) is described. transgenic nicotiana benthamiana plants containing one copy of the cassette stably integrated into their genome were superinfected with tylcsv, which mobilized and replicated the cassette as an episomal replicon. the expression of the reporter gene (the gfp gene) was thereby modified. whereas gfp fluorescen ... | 2006 | 16537630 |
| differential methylation of the circular dna in geminiviral minichromosomes. | geminiviral minichromosomes were purified to explore epigenetic modifications. the levels of methylation in their covalently closed circular dna were examined with the help of methylation-dependent restriction (mdr). dna with 12 superhelical turns was preferentially modified, indicating minichromosomes with 12 nucleosomes leaving an open gap. mdr digestion yielded a specific product of genomic length, which was cloned and sanger-sequenced, or amplified following ligation-mediated rolling circle ... | 2016 | 27716464 |
| form follows function in geminiviral minichromosome architecture. | a comprehensive survey on the viral minichromosomes of the begomoviruses abutilon mosaic virus, tomato yellow leaf curl sardinia virus, african cassava mosaic virus, indian cassava mosaic virus (family geminiviridae) during the course of infections in nicotiana benthamiana is summarized. using optimized one-dimensional and two-dimensional gel systems combined with blot hybridization and a standardized evaluation, discrete and heterogeneous virus-specific signals with different dna forms were com ... | 2015 | 25445344 |
| deciphering the biology of deltasatellites from the new world: maintenance by new world begomoviruses and whitefly transmission. | deltasatellites are small noncoding dna satellites associated with begomoviruses. the study presented here has investigated the biology of two deltasatellites found in wild malvaceous plants in the new world (nw). infectious clones of two nw deltasatellites (from malvastrum coromandelianum and sidastrum micranthum) and associated begomoviruses were constructed. infectivity in nicotiana benthamiana and their natural malvaceous hosts was assessed. the nw deltasatellites were not able to spread aut ... | 2016 | 27400152 |
| c2 from beet curly top virus promotes a cell environment suitable for efficient replication of geminiviruses, providing a novel mechanism of viral synergism. | • geminiviruses are plant viruses with circular, single-stranded (ss) dna genomes that infect a wide range of species and cause important losses in agriculture. geminiviruses do not encode their own dna polymerase, and rely on the host cell machinery for their replication. • here, we identify a positive effect of the curtovirus beet curly top virus (bctv) on the begomovirus tomato yellow leaf curl sardinia virus (tylcsv) infection in nicotiana benthamiana plants. • our results show that this pos ... | 2012 | 22404507 |
| a nuclear-replicating viroid antagonizes infectivity and accumulation of a geminivirus by upregulating methylation-related genes and inducing hypermethylation of viral dna. | dna methylation and post-transcriptional gene silencing play critical roles in controlling infection of single-stranded (ss) dna geminiviruses and ssrna viroids, respectively, but both pathogens can counteract these host defense mechanisms and promote their infectivity. moreover, a specific role of dna methylation in viroid-host interactions is not yet confirmed. here, using an experimental system where two nuclear-replicating agents, the geminivirus tomato yellow leaf curl sardinia virus (tylcs ... | 2016 | 27739453 |
| infectivity, effects on helper viruses and whitefly transmission of the deltasatellites associated with sweepoviruses (genus begomovirus, family geminiviridae). | begomoviruses (family geminiviridae) are whitefly-transmitted viruses with single-stranded dna genomes that are frequently associated with dna satellites. these satellites include non-coding satellites, for which the name deltasatellites has been proposed. although the first deltasatellite was identified in the late 1990s, little is known about the effects they have on infections of their helper begomoviruses. recently a group of deltasatellites were identified associated with sweepoviruses, a g ... | 2016 | 27453359 |
| the non-canonical tomato yellow leaf curl virus recombinant that displaced its parental viruses in southern morocco exhibits a high selective advantage in experimental conditions. | recombination events are frequently inferred from the increasing number of sequenced viral genomes, but their impact on natural viral populations has rarely been evidenced. tylcv-is76 is a recombinant (begomovirus,geminiviridae) between the israel strain of tomato yellow leaf curl virus (tylcv-il) and the spanish strain of tomato yellow leaf curl sardinia virus (tylcsv-es) that was generated most probably in the late 1990s in southern morocco (souss). its emergence in the 2000s coincided with th ... | 2016 | 27902403 |
| transcriptomics of tomato plants infected with tylcsv or expressing the central tylcsv rep protein domain uncover changes impacting pathogen response and senescence. | to establish a successful infection viruses need to overcome plant innate immune responses and redirect host gene expression for their multiplication and diffusion. tomato yellow leaf curl sardinia virus (tylcsv) is a geminivirus, which causes significant economic losses in tomato. the multifunctional replication associated geminivirus protein (rep) has an important role during viral infection. in particular, the rep central domain spanning from aa 120 to 180 is known to interact with viral and ... | 2016 | 26966899 |
| the c2 protein of tomato yellow leaf curl sardinia virus acts as a pathogenicity determinant and a 16-amino acid domain is responsible for inducing a hypersensitive response in plants. | the role of the c2 protein in the pathogenicity of tomato yellow leaf curl sardinia virus (tylcsv) was investigated. here we report that agrobacterium-mediated transient expression of tylcsv c2 resulted in a strong hypersensitive response (hr) in nicotiana benthamiana, n. tabacum, and arabidopsis thaliana, with induction of plant cell death and production of h2o2. since hr is not evident in plants infected by tylcsv, it is expected that tylcsv encodes a gene (or genes) that counters this respons ... | 2016 | 26826600 |
| immunity to tomato yellow leaf curl virus in transgenic tomato is associated with accumulation of transgene small rna. | gene silencing is a natural defense response of plants against invading rna and dna viruses. the rna post-transcriptional silencing system has been commonly utilized to generate transgenic crop plants that are "immune" to plant virus infection. here, we applied this approach against the devastating dna virus tomato yellow leaf curl virus (tylcv) in its host tomato (solanum lycopersicum l.). to generate broad resistance to a number of different tylcv viruses, three conserved sequences (the interg ... | 2015 | 26255053 |
| real-time pcr protocols for the quantification of the begomovirus tomato yellow leaf curl sardinia virus in tomato plants and in its insect vector. | tomato yellow leaf curl sardinia virus (tylcsv) (geminiviridae) is an important pathogen, transmitted by the whitefly bemisia tabaci, that severely affects the tomato production in the mediterranean basin. here, we describe real-time pcr protocols suitable for relative and absolute quantification of tylcsv in tomato plants and in whitefly extracts. using primers and probe specifically designed for tylcsv, the protocols for relative quantification allow to compare the amount of tylcsv present in ... | 2015 | 25287496 |
| a sensitive method for the quantification of virion-sense and complementary-sense dna strands of circular single-stranded dna viruses. | circular single-stranded dna (ssdna) viruses are the smallest viruses known to infect eukaryotes. high recombination and mutation rates have conferred these viruses with an evolutionary potential that has facilitated their emergence. their damaging effects on livestock (circoviruses) and crops (geminiviruses and nanoviruses), and the ubiquity of anelloviruses in human populations and other mammalian species, have resulted in increased interest in better understanding their epidemiology and infec ... | 2014 | 25241765 |
| transcriptomics of the interaction between the monopartite phloem-limited geminivirus tomato yellow leaf curl sardinia virus and solanum lycopersicum highlights a role for plant hormones, autophagy and plant immune system fine tuning during infection. | tomato yellow leaf curl sardinia virus (tylcsv), a dna virus belonging to the genus begomovirus, causes severe losses in tomato crops. it infects only a limited number of cells in the vascular tissues, making difficult to detect changes in host gene expression linked to its presence. here we present the first microarray study of transcriptional changes induced by the phloem-limited geminivirus tylcsv infecting tomato, its natural host. the analysis was performed on the midrib of mature leaves, a ... | 2014 | 24587146 |
| analysis of small rnas derived from tomato yellow leaf curl sardinia virus reveals a cross reaction between the major viral hotspot and the plant host genome. | rna silencing is a defense mechanism exploited by plants against viruses. upon infection, viral genomes and their transcripts are processed by dicer-like (dcl) ribonucleases into viral small interfering rnas (vsrnas) of 21-24 nucleotides that further guide silencing of viral transcripts. to get an insight into the molecular interaction between tomato and the monopartite phloem-limited begomovirus tomato yellow leaf curl sardinia virus (tylcsv), a pathogen inducing a devastating disease of tomato ... | 2013 | 24091361 |
| the arbuscular mycorrhizal symbiosis attenuates symptom severity and reduces virus concentration in tomato infected by tomato yellow leaf curl sardinia virus (tylcsv). | the arbuscular mycorrhizal (am) symbiosis is considered a natural instrument to improve plant health and productivity since mycorrhizal plants often show higher tolerance to abiotic and biotic stresses. however, the impact of the am symbiosis on infection by viral pathogens is still largely uncertain and little explored. in the present study, tomato plants were grown under controlled conditions and inoculated with the am fungus funneliformis mosseae. once the mycorrhizal colonization had develop ... | 2014 | 24072193 |
| tomato yellow leaf curl sardinia virus-resistant tomato plants expressing the multifunctional n-terminal domain of the replication-associated protein show transcriptional changes resembling stress-related responses. | the n-terminal domain (amino acids 1-130) of the replication-associated protein (rep130 ) of tomato yellow leaf curl sardinia virus (tylcsv) retains the ability of full-length rep to localize to the nucleus and to down-regulate c1 transcription when ectopically expressed in plants, both functions being required to inhibit homologous viral replication. in this study, we analysed the effect of rep130 expression on virus resistance and the plant transcriptome in the natural and agronomically import ... | 2014 | 23910556 |
| recombination profiles between tomato yellow leaf curl virus and tomato yellow leaf curl sardinia virus in laboratory and field conditions: evolutionary and taxonomic implications. | tomato yellow leaf curl sardinia virus and tomato yellow leaf curl virus have co-existed in italian tomato crops since 2002 and have reached equilibrium, with plants hosting molecules of both species plus their recombinants being the most frequent case. recombination events are studied in field samples, as well as in experimental co-infections, when recombinants were detected as early as 45 days following inoculation. in both conditions, recombination breakpoints were essentially absent in regio ... | 2012 | 22971824 |
| functional analysis of gene-silencing suppressors from tomato yellow leaf curl disease viruses. | tomato yellow leaf curl disease (tylcd) is caused by a complex of phylogenetically related begomovirus spp. that produce similar symptoms when they infect tomato plants but have different host ranges. in this work, we have evaluated the gene-silencing-suppression activity of c2, c4, and v2 viral proteins isolated from the four main tylcd-causing strains in spain in nicotiana benthamiana. we observed varying degrees of local silencing suppression for each viral protein tested, with v2 proteins fr ... | 2012 | 22712505 |
| an rgg sequence in the replication-associated protein (rep) of tomato yellow leaf curl sardinia virus is involved in transcriptional repression and severely impacts resistance in rep-expressing plants. | truncated versions of the replication-associated protein (rep) of tomato yellow leaf curl sardinia virus (tylcsv) can interfere with various viral functions and the n-terminal 130 aa are sufficient for strongly inhibiting c1-gene transcription and virus replication and confer resistance in transgenic plants. in this work, we analysed the relevance of an rgg sequence at aa 124-126, highly conserved in begomoviruses, in these inhibitory functions as well as in the subcellular localization o ... | 2011 | 20943892 |
| the complete nucleotide sequence of an isolate of tomato yellow leaf curl sardinia virus found in sicily. | partial sequences of tomato yellow leaf curl sardinia virus (tylcsv) derived from tomato samples collected in sicily in 1999, 2002 and 2004 indicated the presence of a tylcsv different from the one previously described as the sic strain. here, we report a complete dna sequence that is classified as belonging to the tylcsv type strain (sar strain), confirming the co-existence in sicily of virus populations of both strains. moreover, comparisons between this new sequence and those of the two recom ... | 2010 | 20665057 |
| virion stability is important for the circulative transmission of tomato yellow leaf curl sardinia virus by bemisia tabaci, but virion access to salivary glands does not guarantee transmissibility. | the capsid protein (cp) of the monopartite begomovirus tomato yellow leaf curl sardinia virus (tylcsv), family geminiviridae, is indispensable for plant infection and vector transmission. a region between amino acids 129 and 152 is critical for virion assembly and insect transmissibility. two previously described mutants, one with a double q129p q134h mutation (pnhd) and another with a further d152e change (pnhe), were found nontransmissible (nt). another nt mutant with a single n130d change (qd ... | 2009 | 19321611 |
| high genetic stability of the begomovirus tomato yellow leaf curl sardinia virus in southern spain over an 8-year period. | abstract the evolution of the plant single-stranded dna virus tomato yellow leaf curl sardinia virus (tylcsv) (genus begomovirus, family geminiviridae) has been monitored for 8 years after its appearance in southern spain. variation within three genomic regions of 166 tylcsv isolates collected from three locations was assessed by single-strand conformation polymorphism (sscp) analysis. according to sscp, the intergenic region (ir) was the most variable. low genetic diversity was found within the ... | 2002 | 18942962 |
| real-time pcr for the quantitation of tomato yellow leaf curl sardinia virus in tomato plants and in bemisia tabaci. | tomato yellow leaf curl sardinia virus (tylcsv) (geminiviridae) is an important pathogen severely affecting tomato production in the mediterranean basin. although diagnostic protocols are available for its detection in plants and its vector bemisia tabaci (gennadius), suitable tools for estimating and comparing viral loads in plant and insect tissues are needed. in this paper, real-time pcr methods are described for quantitation of tylcsv in both tomato plant and whitefly extracts. the dna extra ... | 2008 | 17980920 |
| development of a real-time pcr for tomato yellow leaf curl sardinia virus. | recently, tomato yellow leaf curl disease has become important for the tomato grown both in greenhouse and field conditions in tunisia. here, we describe a rapid, specific, reliable, and sensitive real-time pcr, based on taqman chemistry, for tomato yellow leaf curl sardinia virus (tylcsv). this method proved suitable for the detection and quantification of this virus in tomato, pepper and bean plants. it detected the virus even in the samples that were negative by conventional assays. | 2006 | 16808327 |
| tomato yellow leaf curl sardinia virus can overcome transgene-mediated rna silencing of two essential viral genes. | to evaluate rna silencing for the control of geminivirus infection, two classes of post-transcriptionally silenced (pts) plants were tested using tomato yellow leaf curl sardinia virus (tylcsv) rep-210-transgenic plants, a sensexantisense hybrid and two multicopy sense lines. in both classes, pts plants accumulated low or undetectable amounts of rep-210 protein and mrna but high amounts of rep-210 small interfering rnas. pts plants were susceptible to tylcsv when challenged by agroinoculation or ... | 2004 | 15166460 |