| resistance to tospoviruses in nicotiana benthamiana transformed with the n gene of tomato spotted wilt virus: correlation between transgene expression and protection in primary transformants. | nicotiana benthamiana was transformed with the nucleoprotein (n) gene of an italian isolate of tomato spotted wilt virus (tswv). forty-five t1 primary transformant lines were analyzed for the expression of n protein and for resistance to tswv and three other tospoviruses: impatiens necrotic spot virus (insv), groundnut bud necrosis virus (gbnv), and groundnut ringspot virus (grsv). thirteen of these lines were further characterized. resistance to all tswv isolates tested was found in two lines. ... | 1995 | 7772806 |
| broad resistance to tospoviruses in transgenic tobacco plants expressing three tospoviral nucleoprotein gene sequences. | transgenic tobacco plants have been obtained expressing nucleoprotein (n) gene sequences of three different tospoviruses known to affect vegetable crops: tomato spotted wilt virus (tswv), tomato chlorotic spot virus (tcsv), and groundnut ringspot virus (grsv). the chimeric plant transformation vector used comprised the three viral n gene sequences, each with a copy of the camv 35s promoter and the nos terminator. despite the high levels of homology between the different n gene sequences (74-82%) ... | 1995 | 7772807 |
| classification of tospoviruses based on phylogeny of nucleoprotein gene sequences. | the nucleotide sequences of the nucleoprotein (n) genes of seven tospovirus isolates representing three serogroups were determined and used to establish phylogenetic parameters to delineate species within the tospovirus genus of the bunyaviridae. a high sequence divergence (55.9% identity at the nucleotide level) was observed between isolates of serogroup i (tomato spotted wilt virus) and isolates of serogroup iii (impatiens necrotic spot virus). the serogroup ii isolates take an intermediate po ... | 1993 | 8429298 |
| a polyclonal antiserum against a recombinant viral protein combines specificity with versatility. | a polyclonal rabbit antiserum was obtained to the nucleoprotein of tomato spotted wilt tospovirus expressed as a recombinant fusion protein in e. coli. in indirect plate trapping elisa, the antiserum gave similar titres against purified tswv nucleocapsids in native form, the fusion protein and the carrier protein. the crude antiserum was also tested by western blotting, indirect plate trapping elisa and immunogold electron microscopy of thin sections: purified immunoglobulins were tested by das- ... | 1996 | 8882651 |
| an improved method for the detection of tospoviruses using the polymerase chain reaction. | a reverse transcription-polymerase chain reaction (rt-pcr)-based assay for the detection of tomato spotted wilt virus (tswv) has been improved and extended to enable the detection of additional tospoviruses. in addition to tswv-specific primers, two further pairs of primers have been designed, one pair which specifically detects impatiens necrotic spot virus (insv) and another which detects all tospoviruses tested, including tswv, insv, tomato chlorotic spot virus and groundnut ringspot virus. a ... | 1996 | 8919828 |
| clustering of argentinean tospoviruses with existing species in the genus by sequence analysis of a 450-nucleotide rna region of the n gene. | the genomic diversity of argentine tospoviruses from different geographical areas, and from several distinct crops was analysed here. for each isolate, rt-pcr, cloning and sequencing of a 450 nt fragment of the n gene were performed. comparisons of rna and predicted amino acid sequence identity and similarity were made. a partial sequence of the n gene was able to classify our local isolates within three tospovirus species previously described (tomato spotted wilt virus, tswv; tomato chlorotic s ... | 1996 | 9035370 |
| serological comparison of tospoviruses with polyclonal antibodies produced against the main structural proteins of tomato spotted wilt virus. | a new purification procedure for the tospoviruses of serogroups ii and iii was developed. sds-polyacrylamide gel electrophoresis of purified tomato spotted wilt virus (tswv; serogroup i), groundnut ringspot virus (grsv: serogroup ii), tomato chlorotic spot virus (tcsv; serogroup ii) and impatiens necrotic spot virus (insv; serogroup iii) showed that the glycoprotein g2 of serogroup ii members differs significantly in size from that of the serogroup i virus. western immunoblot analysis using poly ... | 1997 | 9170504 |
| constitutive expression of interferon-induced human mxa protein in transgenic tobacco plants does not confer resistance to a variety of rna viruses. | mxa is a key component in the interferon-induced antiviral defense in humans. after viral infections, mxa is rapidly induced and accumulates in the cytoplasm. the multiplication of many rna viruses, including all bunyaviruses tested so far, is inhibited by mxa. these findings prompted us to express mxa in plants in an attempt to create resistance to tospoviruses. here, we report the generation of transgenic tobacco plants that constitutively express mxa under the control of the 35 s cauliflower ... | 2000 | 11206971 |
| sequence analysis of the glycoproteins of tomato chlorotic spot virus and groundnut ringspot virus and comparison with other tospoviruses. | the tospoviruses tomato chlorotic spot virus (tcsv) and groundnut ringspot virus (grsv) cause high economic losses in several vegetable crops in brazil. the glycoprotein precursor coding sequence was still not available for these two viruses. in this study, the 3' 4 kb m rna of tcsv and grsv genome was cloned and sequenced. the sequences were compiled with the available 5' region sequence (nsm gene and 5' utr) of the same isolates. the m rna of tcsv was deduced as formed by 4,882 nucleotides, wh ... | 2004 | 15550772 |
| serological and molecular characterization of peanut chlorotic fan-spot virus, a new species of the genus tospovirus. | abstract to clarify the serological relationship of peanut chlorotic fan-spot virus (pcfv) with other tospoviruses, antisera were produced against the nucleocapsid (n) proteins of this virus and tospoviruses from four serogroups including tomato spotted wilt virus (tswv), impatiens necrotic spot virus (insv), groundnut ringspot virus (grsv), and watermelon silver mottle virus (wsmov). in immunodiffusion tests, the antisera only reacted with their homologous antigens. similar results were noticed ... | 2001 | 18944231 |
| application of phage display in selecting tomato spotted wilt virus-specific single-chain antibodies (scfvs) for sensitive diagnosis in elisa. | abstract a panel of recombinant single-chain antibodies (scfvs) against structural proteins of tomato spotted wilt virus (tswv) was retrieved from a human combinatorial scfv antibody library using the novel phage display technique. after subcloning the encoding dna sequences in the expression vector pskap/s, which allowed the scfvs to be expressed as alkaline phosphatase fusion proteins, 17 different scfv antibodies were obtained. of these, 12 scfvs were directed against the nucleoprotein (n) an ... | 2000 | 18944607 |
| a distinct tospovirus causing necrotic streak on alstroemeria sp. in colombia. | a tospovirus causing necrotic streaks on leaves was isolated from alstroemeria sp. in colombia. infected samples reacted positively with tomato spotted wilt virus (tswv) antiserum during preliminary serological tests. further analysis revealed a close serological relationship to tomato chlorotic spot virus (tcsv) and groundnut ringspot virus (grsv). a major part of the s-rna segment, encompassing the nucleocapsid (n) protein gene, the 5' untranslated region and a part of the intergenic region 3' ... | 2010 | 20151164 |
| expression of a modified nucleocapsid-protein of tomato spotted wilt virus (tswv) confers resistance against tswv and groundnut ringspot virus (grsv) by blocking systemic spread. | summary tobacco transformed with a construct comprising the nucleocapsid-protein (n) gene of tomato spotted wilt virus (tswv) and the 5' non-translated leader sequence of plum pox virus (ppv) as a translation enhancer displays unusually broad resistance against tospoviruses. contrary to expectations, the transgenic plants did not express a higher level of tswv n protein than control plants harbouring the n gene without the ppv enhancer. instead, expression of an n-terminally elongated n protein, ... | 2004 | 20565598 |
| diverging affinity of tospovirus rna silencing suppressor proteins, nss, for various rna duplex molecules. | the tospovirus nss protein was previously shown to suppress the antiviral rna silencing mechanism in plants. here the biochemical analysis of nss proteins from different tospoviruses, using purified nss or nss containing cell extracts, is described. the results showed that all tospoviral nss proteins analyzed exhibited affinity to small double-stranded rna molecules, i.e., small interfering rnas (sirnas) and micro-rna (mirna)/mirna* duplexes. interestingly, the nss proteins from tomato spotted w ... | 2010 | 20739523 |
| a natural m rna reassortant arising from two species of plant- and insect-infecting bunyaviruses and comparison of its sequence and biological properties to parental species. | reassortment allows multicomponent viruses to exchange genome segments, a process well-documented in the vertebrate- and arthropod-infecting members of the family bunyaviridae but not between distinct species of the plant- and insect-infecting members of the genus tospovirus. genome sequence comparisons of a virus causing severe tospovirus-like symptoms in florida tomato with groundnut ringspot virus (grsv) and tomato chlorotic spot virus (tcsv) demonstrated that reassortment has occurred, with ... | 2011 | 21382631 |
| molecular characterization of the rna-dependent rna polymerase from groundnut ringspot virus (genus tospovirus, family bunyaviridae). | groundnut ringspot virus is a negative-sense single-stranded rna virus that belongs to the genus tospovirus and is the prevalent member of this genus in brazil. this work presents the nucleotide sequence of the l rna, with a single open reading frame of 2873 amino acids in the complementary strand corresponding to the rna-dependent rna polymerase (l protein), as well as the characterization of conserved domains of the l protein by in silico analysis. phylogenetic analysis of different l protein ... | 2011 | 21442231 |
| sequence determination and analysis of the nss genes of two tospoviruses. | the tospoviruses groundnut ringspot virus (grsv) and zucchini lethal chlorosis virus (zlcv) cause severe losses in many crops, especially in solanaceous and cucurbit species. in this study, the non-structural nss gene and the 5'utrs of these two biologically distinct tospoviruses were cloned and sequenced. the nss sequence of grsv and zlcv were both 1,404 nucleotides long. pairwise comparison showed that the nss amino acid sequence of grsv shared 69.6% identity with that of zlcv and 75.9% identi ... | 2011 | 22187101 |
| homology modeling and molecular dynamics provide structural insights into tospovirus nucleoprotein. | tospovirus is a plant-infecting genus within the family bunyaviridae, which also includes four animal-infecting genera: hantavirus, nairovirus, phlebovirus and orthobunyavirus. compared to these members, the structures of tospovirus proteins still are poorly understood. despite multiple studies have attempted to identify candidate n protein regions involved in rna binding and protein multimerization for tospovirus using yeast two-hybrid systems (y2hs) and site-directed mutagenesis, the tospoviru ... | 2016 | 28105914 |
| development of a microarray for simultaneous detection and differentiation of different tospoviruses that are serologically related to tomato spotted wilt virus. | tospoviruses, the plant-infecting genus in the family bunyaviridae, are thrips borne and cause severe agricultural losses worldwide. based on the serological relationships of the structural nucleocapsid protein (np), the current tospoviruses are divided into six serogroups. the use of np-antisera is convenient for virus detection, but it is insufficient to identify virus species grouped in a serogroup due to the serological cross-reaction. alternatively, virus species can be identified by the n ... | 2017 | 28081705 |
| analysis of the coding-complete genomic sequence of groundnut ringspot virus suggests a common ancestor with tomato chlorotic spot virus. | groundnut ringspot virus (grsv) and tomato chlorotic spot virus (tcsv) share biological and serological properties, so their identification is carried out by molecular methods. their genomes consist of three segmented rnas: l, m and s. the finding of a reassortant between these two viruses may complicate correct virus identification and requires the characterization of the complete genome. therefore, we present for the first time the complete sequences of all the genes encoded by a grsv isolate. ... | 2016 | 27260536 |
| analysis of tospovirus nss proteins in suppression of systemic silencing. | rna silencing is a sequence-specific gene regulation mechanism that in plants also acts antiviral. in order to counteract antiviral rna silencing, viruses have evolved rna silencing suppressors (rss). in the case of tospoviruses, the non-structural nss protein has been identified as the rss. although the tomato spotted wilt virus (tswv) tospovirus nss protein has been shown to exhibit affinity to long and small dsrna molecules, its ability to suppress the non-cell autonomous part of rna silencin ... | 2015 | 26275304 |
| genetic and serological characterization of chrysanthemum stem necrosis virus, a member of the genus tospovirus. | chrysanthemum stem necrosis virus (csnv) is a member of a tentative tospovirus species. in this study, the complete genomic sequence of the japanese csnv isolate tcch07a was determined. the l rna is 8960 nt long and encodes the 331.0-kda rna-dependent rna polymerase. the m rna is 4828 nt long and encodes the 34.1-kda movement protein (nsm) and the 127.7-kda glycoprotein precursor (gn/gc). the s rna is 2949 nt long and encodes the 52.4-kda silencing suppressor protein (nss) and the 29.3-kda nucle ... | 2015 | 25427981 |
| emergence of groundnut ringspot virus and tomato chlorotic spot virus in vegetables in florida and the southeastern united states. | groundnut ringspot virus (grsv) and tomato chlorotic spot virus (tcsv) are two emerging tospoviruses in florida. in a survey of the southeastern united states, grsv and tcsv were frequently detected in solanaceous crops and weeds with tospovirus-like symptoms in south florida, and occurred sympatrically with tomato spotted wilt virus (tswv) in tomato and pepper in south florida. tswv was the only tospovirus detected in other survey locations, with the exceptions of grsv from tomato (solanum lyco ... | 2015 | 25317844 |
| analysis of tomato spotted wilt virus nss protein indicates the importance of the n-terminal domain for avirulence and rna silencing suppression. | recently, tomato spotted wilt virus (tswv) nonstructural protein nss has been identified unambiguously as an avirulence (avr) determinant for tomato spotted wilt (tsw)-based resistance. the observation that nss from two natural resistance-breaking isolates had lost rna silencing suppressor (rss) activity and avr suggested a link between the two functions. to test this, a large set of nss mutants was generated by alanine substitutions in nss from resistance-inducing wild-type strains (nss(ri) ), ... | 2014 | 24103150 |
| the nsm proteins of phylogenetically related tospoviruses trigger sw-5b-mediated resistance dissociated of their cell-to-cell movement function. | the cell-to-cell movement protein (nsm) of tomato spotted wilt virus (tswv) has been recently identified as the effector of the single dominant sw-5b resistance gene from tomato (solanum lycopersicum l.). although most tswv isolates shows a resistance-inducing (ri) phenotype, regular reports have appeared on the emergence of resistance-breaking (rb) isolates in tomato fields, and suggested a strong association with two point mutations (c118y and t120n) in the nsm protein. in this study the sw-5b ... | 2017 | 28754561 |