The Experts below are selected from a list of 1344 Experts worldwide ranked by ideXlab platform
Tsung-chi Chen - One of the best experts on this subject based on the ideXlab platform.
-
Development of a generic method for inspection of Tospoviruses
European Journal of Plant Pathology, 2018Co-Authors: Kuo-shiou Huang, Yun-chi Wang, Siang-ling Li, Tsung-chi ChenAbstract:Members of the genus Tospovirus which can infect plants in the family Bunyaviridae , possess quasi-spherical enveloped particles (80–120 nm in diameter) and a segmented tripartite single-stranded RNA genome, with large (L), medium (M) and small (S) RNA segments. Tospoviruses are vectored by thrips in a persistent manner and cause yield losses of numerous economic crops worldwide. Inspection is an important measure to prevent invasion of Tospoviruses. However, the increase of new virus species makes inspection challenging. In this study, a degenerate primer pair dTospo-F2/dTospo-R2 was designed from the conserved regions of the tospoviral L RNA sequences and used for the tospovirus detection in SYBR Green I-based quantitative real-time reverse transcription-polymerase chain reaction (RT-qPCR). The designed primers could amplify specific products from all tested 20 tospovirus species. The specificity of amplifications was validated by melting curve assays, agarose gel electrophoresis and direct sequencing of amplicons. Furthermore, the degenerate primer pair was used in RT-qPCR to detect tospovirus infections from field cowpea and sweet pepper samples. Sequencing of the amplicons confirmed the identity of the viruses as Groundnut chlorotic fan-spot virus (GCFSV) from the cowpea and Tomato spotted wilt virus from the sweet pepper. Our results demonstrated that the degenerate primer pair dTospo-F2/dTospo-R2 is highly specific to Tospoviruses, and when used in RT-qPCR, it greatly simplifies and enhances the efficacy of the inspection of Tospoviruses. Additionally, this is the first report of GCFSV infected cowpea.
-
Development of a microarray for simultaneous detection and differentiation of different Tospoviruses that are serologically related to Tomato spotted wilt virus
Virology Journal, 2017Co-Authors: He-yi Ye, Tsang-hai Chen, Tsung-chi ChenAbstract:Background 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 gene amplification using specific primers. Tomato spotted wilt virus (TSWV) is the type species of the genus Tospovirus and one of the most destructive plant viruses. Eight known Tospoviruses, Alstroemeria necrotic streak virus (ANSV), Chrysanthemum stem necrosis virus (CSNV), Groundnut ringspot virus (GRSV), Impatiens necrotic spot virus (INSV), Melon severe mosaic virus (MeSMV), Pepper necrotic spot virus (PNSV), Tomato chlorotic spot virus (TCSV) and Zucchini lethal chlorosis virus (ZLCV), sharing serological relatedness with TSWV in NP, are grouped in the TSWV serogroup. Most of the TSWV-serogroup viruses prevail in Europe and America. An efficient diagnostic method is necessary for inspecting these Tospoviruses in Asia, including Taiwan. Methods A microarray platform was developed for simultaneous detection and identification of TSWV-serogroup Tospoviruses. Total RNAs extracted from Chenopodium quinoa leaves separately inoculated with ANSV, CSNV, GRSV, INSV, TCSV and TSWV were used for testing purposes. The 5’-biotinylated degenerate forward and reverse primers were designed from the consensus sequences of N genes of TSWV-serogroup Tospoviruses for reverse transcription-polymerase chain reaction (RT-PCR) amplification. Virus-specific oligonucleotide probes were spotted on the surface of polyvinyl chloride (PVC) chips to hybridize with PCR products. The hybridization signals were visualized by hydrolysis of NBT/BCIP with streptavidine-conjugated alkaline phosphatase. The microarray was further applied to diagnose virus infection in field crop samples. Results Amplicons of approximately 0.46 kb were amplified from all tested TSWV-serogroup Tospoviruses by RT-PCR using the degenerate primer pair Pr-dTS-f/Pr-dTS-r. Virus species were identified on chips by hybridization of PCR products with respective virus-specific probes. The microarray was successfully used to diagnose TSWV infection in field pepper samples. Conclusions In this study, a rapid, sensitive and precise microarray method has been developed to simultaneously detect and identify six TSWV-serogroup Tospoviruses. The microarray platform provides a great potential to explore Tospoviruses that can help researchers and quarantine staff to prevent invasions of Tospoviruses.
-
Development of a microarray for simultaneous detection and differentiation of different Tospoviruses that are serologically related to Tomato spotted wilt virus.
Virology Journal, 2017Co-Authors: Lu-yuan Liu, Tsang-hai Chen, Tsung-chi ChenAbstract: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 gene amplification using specific primers. Tomato spotted wilt virus (TSWV) is the type species of the genus Tospovirus and one of the most destructive plant viruses. Eight known Tospoviruses, Alstroemeria necrotic streak virus (ANSV), Chrysanthemum stem necrosis virus (CSNV), Groundnut ringspot virus (GRSV), Impatiens necrotic spot virus (INSV), Melon severe mosaic virus (MeSMV), Pepper necrotic spot virus (PNSV), Tomato chlorotic spot virus (TCSV) and Zucchini lethal chlorosis virus (ZLCV), sharing serological relatedness with TSWV in NP, are grouped in the TSWV serogroup. Most of the TSWV-serogroup viruses prevail in Europe and America. An efficient diagnostic method is necessary for inspecting these Tospoviruses in Asia, including Taiwan. A microarray platform was developed for simultaneous detection and identification of TSWV-serogroup Tospoviruses. Total RNAs extracted from Chenopodium quinoa leaves separately inoculated with ANSV, CSNV, GRSV, INSV, TCSV and TSWV were used for testing purposes. The 5’-biotinylated degenerate forward and reverse primers were designed from the consensus sequences of N genes of TSWV-serogroup Tospoviruses for reverse transcription-polymerase chain reaction (RT-PCR) amplification. Virus-specific oligonucleotide probes were spotted on the surface of polyvinyl chloride (PVC) chips to hybridize with PCR products. The hybridization signals were visualized by hydrolysis of NBT/BCIP with streptavidine-conjugated alkaline phosphatase. The microarray was further applied to diagnose virus infection in field crop samples. Amplicons of approximately 0.46 kb were amplified from all tested TSWV-serogroup Tospoviruses by RT-PCR using the degenerate primer pair Pr-dTS-f/Pr-dTS-r. Virus species were identified on chips by hybridization of PCR products with respective virus-specific probes. The microarray was successfully used to diagnose TSWV infection in field pepper samples. In this study, a rapid, sensitive and precise microarray method has been developed to simultaneously detect and identify six TSWV-serogroup Tospoviruses. The microarray platform provides a great potential to explore Tospoviruses that can help researchers and quarantine staff to prevent invasions of Tospoviruses.
-
Percentages of nucleotide (nt) and amino acid (aa) identity of the L and M RNA-encoded genes of Groundnut chlorotic fan-spot virus (GCFSV) compared with those of other Tospoviruses.
2017Co-Authors: Wan-chen Chou, Shih-shun Lin, Shyi-dong Yeh, Ying-che Peng, Ya-hsu Fan, Tsung-chi ChenAbstract:Percentages of nucleotide (nt) and amino acid (aa) identity of the L and M RNA-encoded genes of Groundnut chlorotic fan-spot virus (GCFSV) compared with those of other Tospoviruses.
-
Phylogenetic analyses of the encoded proteins of the L and M RNAs of Groundnut chlorotic fan-spot virus (GCFSV).
2017Co-Authors: Wan-chen Chou, Shih-shun Lin, Shyi-dong Yeh, Ying-che Peng, Ya-hsu Fan, Tsung-chi ChenAbstract:(A) The conserved motifs of the RNA-dependent RNA polymerases (RdRps) of Tospoviruses are compared, and the consensus sequences are shown in bold. The identical residues within the same motif are underlined. (B) Phylogenetic trees of RdRp, NSm and Gn/Gc precursor. The dendrograms were produced using the Neighbor-Joining algorithm with 1,000 bootstrap replicates. The percentages are shown. See Table 2for the virus names.
Jui-chu Peng - One of the best experts on this subject based on the ideXlab platform.
-
Broad-Spectrum Transgenic Resistance against Distinct Tospovirus Species at the Genus Level. PLoS One 2014
2016Co-Authors: Jui-chu Peng, Tsung-chi Chen, Joseph A. J. Raja, Ching-fu Yang, Wan-chu Chien, Fang-lin Liu, Hsuan Lin, Shyi-dong YehAbstract:Thrips-borne Tospoviruses cause severe damage to crops worldwide. In this investigation, tobacco lines transgenic for individual WLm constructs containing the conserved motifs of the L RNA-encoded RNA-dependent RNA polymerase (L) gene of Watermelon silver mottle virus (WSMoV) were generated by Agrobacterium-mediated transformation. The WLm constructs included: (i) translatable WLm in a sense orientation; (ii) untranslatable WLmt with two stop codons; (iii) untranslatable WLmts with stop codons and a frame-shift; (iv) untranslatable antisense WLmA; and (v) WLmhp with an untranslatable inverted repeat of WLm containing the tospoviral S RNA 39-terminal consensus sequence (59-ATTGCTCT-39) and an NcoI site as a linker to generate a double-stranded hairpin transcript. A total of 46.7–70.0 % transgenic tobacco lines derived from individual constructs showed resistance to the homologous WSMoV; 35.7–100 % plants of these different WSMoV-resistant lines exhibited broad-spectrum resistance against four other serologically unrelated Tospoviruses Tomato spotted wilt virus, Groundnut yellow spot virus, Impatiens necrotic spot virus and Groundnut chlorotic fan-spot virus. The selected transgenic tobacco lines also exhibited broad-spectrum resistance against five additional Tospoviruses from WSMoV and Iris yellow spot virus clades, but not against RNA viruses from other genera. Northern analyses indicated that the broad-spectrum resistance is mediated by RNA silencing. To validate the L conserved region resistance in vegetable crops, the constructs were also used to generate transgenic tomato lines, which also showed effective resistance agains
-
Broad-spectrum transgenic resistance against distinct tospovirus species at the genus level.
PLoS ONE, 2014Co-Authors: Jui-chu Peng, Tsung-chi Chen, Joseph A. J. Raja, Ching-fu Yang, Wan-chu Chien, Chen-hsuan Lin, Fang-lin Liu, Shyi-dong YehAbstract:Thrips-borne Tospoviruses cause severe damage to crops worldwide. In this investigation, tobacco lines transgenic for individual WLm constructs containing the conserved motifs of the L RNA-encoded RNA-dependent RNA polymerase (L) gene of Watermelon silver mottle virus (WSMoV) were generated by Agrobacterium-mediated transformation. The WLm constructs included: (i) translatable WLm in a sense orientation; (ii) untranslatable WLmt with two stop codons; (iii) untranslatable WLmts with stop codons and a frame-shift; (iv) untranslatable antisense WLmA; and (v) WLmhp with an untranslatable inverted repeat of WLm containing the tospoviral S RNA 3′-terminal consensus sequence (5′-ATTGCTCT-3′) and an NcoI site as a linker to generate a double-stranded hairpin transcript. A total of 46.7–70.0% transgenic tobacco lines derived from individual constructs showed resistance to the homologous WSMoV; 35.7–100% plants of these different WSMoV-resistant lines exhibited broad-spectrum resistance against four other serologically unrelated Tospoviruses Tomato spotted wilt virus, Groundnut yellow spot virus, Impatiens necrotic spot virus and Groundnut chlorotic fan-spot virus. The selected transgenic tobacco lines also exhibited broad-spectrum resistance against five additional Tospoviruses from WSMoV and Iris yellow spot virus clades, but not against RNA viruses from other genera. Northern analyses indicated that the broad-spectrum resistance is mediated by RNA silencing. To validate the L conserved region resistance in vegetable crops, the constructs were also used to generate transgenic tomato lines, which also showed effective resistance against WSMoV and other Tospoviruses. Thus, our approach of using the conserved motifs of tospoviral L gene as a transgene generates broad-spectrum resistance against Tospoviruses at the genus level.
-
Serological relationship between Melon yellow spot virus and Watermelon silver mottle virus and differential detection of the two viruses in cucurbits
Archives of Virology, 2010Co-Authors: Tsung-chi Chen, Ya-chi Kang, Yun-yueh Lu, Ying-huey Cheng, Ju-ting Li, Chia-peng Chang, Li-hsin Huang, Jui-chu PengAbstract:Melon yellow spot virus (MYSV), a tentative member of the genus Tospovirus , is considered a distinct serotype due to the lack of a serological relationship with other Tospoviruses in its nucleocapsid protein (NP). Recently, a virus isolate collected from diseased watermelon in central Taiwan (MYSV-TW) was found to react with a rabbit antiserum (RAs) prepared against the NP of Watermelon silver mottle virus (WSMoV), and a monoclonal antibody (MAb) prepared against the common epitope of the NSs proteins of WSMoV-serogroup Tospoviruses, but not with the WSMoV NP-specific MAb, in both enzyme-linked immunosorbent assay (ELISA) and western blotting. In this investigation, both RAs and MAb against MYSV-TW NP were produced. Results of serological tests revealed that the RAs to MYSV-TW NP reacted with the homologous antigen and the crude antigens of members of the WSMoV serogroup, including members of the formal species WSMoV and Peanut bud necrosis virus , and members of three tentative species, Watermelon bud necrosis virus, Capsicum chlorosis virus and Calla lily chlorotic spot virus. The MAb to MYSV-TW NP reacted only with the homologous antigen and the other geographic isolates of MYSV from Japan (JP) and Thailand (TH). Our results of reciprocal tests indicate that the NP and the NSs protein of MYSV are serologically related to those of WSMoV-serogroup Tospoviruses. Furthermore, we show that both the MYSV NP MAb and the WSMoV NP MAb are reliable tools for identification of MYSV and WSMoV from single or mixed infection in field surveys, as verified using species-specific primers in reverse transcription-polymerase chain reaction.
Shyi-dong Yeh - One of the best experts on this subject based on the ideXlab platform.
-
Phylogenetic analyses of the encoded proteins of the L and M RNAs of Groundnut chlorotic fan-spot virus (GCFSV).
2017Co-Authors: Wan-chen Chou, Shih-shun Lin, Shyi-dong Yeh, Ying-che Peng, Ya-hsu Fan, Tsung-chi ChenAbstract:(A) The conserved motifs of the RNA-dependent RNA polymerases (RdRps) of Tospoviruses are compared, and the consensus sequences are shown in bold. The identical residues within the same motif are underlined. (B) Phylogenetic trees of RdRp, NSm and Gn/Gc precursor. The dendrograms were produced using the Neighbor-Joining algorithm with 1,000 bootstrap replicates. The percentages are shown. See Table 2for the virus names.
-
Percentages of nucleotide (nt) and amino acid (aa) identity of the L and M RNA-encoded genes of Groundnut chlorotic fan-spot virus (GCFSV) compared with those of other Tospoviruses.
2017Co-Authors: Wan-chen Chou, Shih-shun Lin, Shyi-dong Yeh, Ying-che Peng, Ya-hsu Fan, Tsung-chi ChenAbstract:Percentages of nucleotide (nt) and amino acid (aa) identity of the L and M RNA-encoded genes of Groundnut chlorotic fan-spot virus (GCFSV) compared with those of other Tospoviruses.
-
Broad-Spectrum Transgenic Resistance against Distinct Tospovirus Species at the Genus Level. PLoS One 2014
2016Co-Authors: Jui-chu Peng, Tsung-chi Chen, Joseph A. J. Raja, Ching-fu Yang, Wan-chu Chien, Fang-lin Liu, Hsuan Lin, Shyi-dong YehAbstract:Thrips-borne Tospoviruses cause severe damage to crops worldwide. In this investigation, tobacco lines transgenic for individual WLm constructs containing the conserved motifs of the L RNA-encoded RNA-dependent RNA polymerase (L) gene of Watermelon silver mottle virus (WSMoV) were generated by Agrobacterium-mediated transformation. The WLm constructs included: (i) translatable WLm in a sense orientation; (ii) untranslatable WLmt with two stop codons; (iii) untranslatable WLmts with stop codons and a frame-shift; (iv) untranslatable antisense WLmA; and (v) WLmhp with an untranslatable inverted repeat of WLm containing the tospoviral S RNA 39-terminal consensus sequence (59-ATTGCTCT-39) and an NcoI site as a linker to generate a double-stranded hairpin transcript. A total of 46.7–70.0 % transgenic tobacco lines derived from individual constructs showed resistance to the homologous WSMoV; 35.7–100 % plants of these different WSMoV-resistant lines exhibited broad-spectrum resistance against four other serologically unrelated Tospoviruses Tomato spotted wilt virus, Groundnut yellow spot virus, Impatiens necrotic spot virus and Groundnut chlorotic fan-spot virus. The selected transgenic tobacco lines also exhibited broad-spectrum resistance against five additional Tospoviruses from WSMoV and Iris yellow spot virus clades, but not against RNA viruses from other genera. Northern analyses indicated that the broad-spectrum resistance is mediated by RNA silencing. To validate the L conserved region resistance in vegetable crops, the constructs were also used to generate transgenic tomato lines, which also showed effective resistance agains
-
Broad-spectrum transgenic resistance against distinct tospovirus species at the genus level.
PLoS ONE, 2014Co-Authors: Jui-chu Peng, Tsung-chi Chen, Joseph A. J. Raja, Ching-fu Yang, Wan-chu Chien, Chen-hsuan Lin, Fang-lin Liu, Shyi-dong YehAbstract:Thrips-borne Tospoviruses cause severe damage to crops worldwide. In this investigation, tobacco lines transgenic for individual WLm constructs containing the conserved motifs of the L RNA-encoded RNA-dependent RNA polymerase (L) gene of Watermelon silver mottle virus (WSMoV) were generated by Agrobacterium-mediated transformation. The WLm constructs included: (i) translatable WLm in a sense orientation; (ii) untranslatable WLmt with two stop codons; (iii) untranslatable WLmts with stop codons and a frame-shift; (iv) untranslatable antisense WLmA; and (v) WLmhp with an untranslatable inverted repeat of WLm containing the tospoviral S RNA 3′-terminal consensus sequence (5′-ATTGCTCT-3′) and an NcoI site as a linker to generate a double-stranded hairpin transcript. A total of 46.7–70.0% transgenic tobacco lines derived from individual constructs showed resistance to the homologous WSMoV; 35.7–100% plants of these different WSMoV-resistant lines exhibited broad-spectrum resistance against four other serologically unrelated Tospoviruses Tomato spotted wilt virus, Groundnut yellow spot virus, Impatiens necrotic spot virus and Groundnut chlorotic fan-spot virus. The selected transgenic tobacco lines also exhibited broad-spectrum resistance against five additional Tospoviruses from WSMoV and Iris yellow spot virus clades, but not against RNA viruses from other genera. Northern analyses indicated that the broad-spectrum resistance is mediated by RNA silencing. To validate the L conserved region resistance in vegetable crops, the constructs were also used to generate transgenic tomato lines, which also showed effective resistance against WSMoV and other Tospoviruses. Thus, our approach of using the conserved motifs of tospoviral L gene as a transgene generates broad-spectrum resistance against Tospoviruses at the genus level.
-
Sequence analysis of S RNA of Calla Lily Chlorotic Spot Virus, a new tospovirus
Acta Horticulturae, 2006Co-Authors: Y.h. Lin, Ching-chung Chen, Shyi-dong Yeh, T.c. Chen, M.h. Chung, H.t. HsuAbstract:Calla lily chlorotic spot virus (CCSV), a tospovirus infecting Calla lily (Zantedeschia spp.) in Taiwan, with symptoms of chlorotic spots on leaves and stems, was previously reported serologically but distantly related to Watermelon silver mottle virus (WSMoV). To further characterize the virus, DNA fragments corresponding to the S RNA of the virus were amplified from total RNA extracted from CCSV-infected plants of Nicotiana benthamiana, cloned and sequenced. The full-length viral strand of the S RNA was determined as 3,172 nucleotides in length, with an inverted repeat at the 5' and 3' ends and two open reading frames in an ambisense arrangement. The 3'-terminal sequence (5'-AUUGCUCU-3') of the viral S RNA was found identical to those of other Tospoviruses, confirming that CCSV belongs to the genus Tospovirus. The N and the NSs proteins of CCSV share low amino acid identities, 20.9 to 65.1% and 19.9 to 66.1%, respectively, with those of reported Tospoviruses. The phylogenetic dendrogram of the N protein of CCSV compared with those of other Tospoviruses in WSMoV serogroup indicates that CCSV is a distinct tospovirus. Thus, based on the results of molecular characterization of S RNA, we conclude that CCSV is a new tospovirus species belonging to WSMoV serogroup.
Dennis Gonsalves - One of the best experts on this subject based on the ideXlab platform.
-
Combining transgenic and natural resistance to obtain broad resistance to tospovirus infection in tomato (Lycopersicon esculentum mill)
Molecular Breeding, 2002Co-Authors: Augustine Gubba, Carol Gonsalves, Mikel R. Stevens, David M. Tricoli, Dennis GonsalvesAbstract:This study was undertaken to develop tomato plants with broad resistanceto Tospoviruses which are a major limiting factor to tomato productionworldwide. A nontransgenic tomato line Stevens-Rodale (S-R), six transgenictomato lines expressing the nucleocapsid (N) protein gene of the lettuceisolate of tomato spotted wilt virus (TSWV-BL), and progeny of the crosses between S-Rand three of the transgenic lines homozygous for the N gene were evaluated fortheir resistance to tospovirus infection in greenhouse inoculation tests. S-Rhas the Sw-5 gene that confers resistance to several TSWVisolates. The six transgenic lines showed high levels of resistance wheninoculated with either TSWV-BL or a tomato isolate from Hawaii (TSWV-H).However, these same plants were highly susceptible to the Brazilian isolate ofgroundnut ringspot virus (GRSV-BR). Plants with the Sw-5 gene were resistant to TSWV-BL and GRSV-BR, but were susceptible to TSWV-H.When inoculated with any of the three viruses, the F_1 progeny of thecrosses exhibited a susceptible, tolerant, or resistant phenotype with a higherproportion of the plants being either tolerant or resistant. When F_2progeny from F_1 resistant plants of each cross were inoculated withany of the three viruses, a higher proportion of tolerant and resistant plantswas observed compared to the F_1 progeny. Our results show thepotential to obtain broad resistance to Tospoviruses by combining transgenicand natural resistance in a single plant.
-
Different mechanisms protect transgenic tobacco against tomato spotted wilt and impatiens necrotic spot Tospoviruses.
Nature Biotechnology, 1993Co-Authors: Sheng-zhi Pang, Jerry L. Slightom, Dennis GonsalvesAbstract:We generated transgenic tobacco plants expressing the sense or antisense untranslatable N coding sequence of the lettuce isolate of tomato spotted wilt virus (TSWV-BL) as well as transgenic plants containing the promoterless N gene of the virus. Both sense and antisense untranslatable N gene RNAs provided protection against homologous and closely related isolates but not against distantly related Tospoviruses. These RNA-mediated protections were most effective in plants that synthesized low levels of the respective RNA species and appears to be achieved through the inhibition of viral replication. Unlike the sense RNA-mediated protection, the level of the antisense RNA-mediated protection depended on the concentration of the inoculum and the size of the test plants. Comparisons with previous results in transgenic plants expressing the intact N gene suggest that resistance to homologous and closely related TSWV isolates in plants that express low levels of the translatable N gene is due to the presence of the N gene transcript and not the N protein. In contrast, resistance to distantly related Tospoviruses is due to accumulation of high levels of the N protein and not due to the presence of the N gene transcript.
R. W. Goldbach - One of the best experts on this subject based on the ideXlab platform.
-
Transgenic tobacco plants expressing the putative movement protein of tomato spotted wilt tospovirus exhibit aberrations in growth and appearance.
Transgenic Research, 1997Co-Authors: Marcel Prins, Richard Kormelink, P. De Haan, M.h.m. Storms, R. W. GoldbachAbstract:Within the Bunyaviridae virus family, members of the genus Tospovirus are unique in their ability to infect plants. A characteristic genetic difference between Tospoviruses and the animal-infecting members of this virus family is the occurrence of an additional gene, denoted NSM, located on the genomic M RNA segment. This gene has previously been implicated in the cell-to-cell movement of this virus during systemic infection. Transgenic tobacco plants have been obtained expressing the NSM protein of tomato spotted wilt virus (TSWV), the type member of the Tospoviruses, from a constitutive promoter. Detectable amounts of the NSM protein could be observed in plants from nine different lines. The protein was only detectable in fractions enriched for cell wall material. More detailed immunogold labelling studies revealed specific association of NSM protein with plasmodesmata. Plants accumulating the NSM protein to detectable levels developed aberrations in growth, resulting in a significant reduction of size and accelerated senescence. In addition, these plants are restricted in their capacity to produce flowers. The results presented provide additional evidence that the NSM protein, by modifying plasmodesmata, represents the cell-to-cell movement function of Tospoviruses. Furthermore, the phenotype of the NSM transgenic plants suggests involvement of the NSM gene product in TSWV symptom expression
-
Molecular and Biological Aspects of Tospoviruses
The Bunyaviridae, 1996Co-Authors: R. W. Goldbach, Dick PetersAbstract:Most members of the Bunyaviridae infect animals but some are able to infect plants. The plant-infecting viruses, which are propagatively transmitted by thrips species, are classified into a separate genus, Tospovirus, named after the type species tomato spotted wilt virus (Francki et al., 1991). Since the late 1980s, when increased knowledge in the molecular biology of tomato spotted wilt virus (TSWV) allowed it to be included in the Bunyaviridae, a number of distinct tospovirus species are still being identified and classified within the same family.
-
Broad resistance to Tospoviruses in transgenic tobacco plants expressing three tospoviral nucleoprotein gene sequences
Molecular Plant-Microbe Interactions, 1995Co-Authors: Marcel Prins, P. De Haan, R. Luyten, M. Van Veller, M. Van Grinsven, R. W. GoldbachAbstract: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%) and the presence of repeated promoter and terminator sequences in this construct, unrearranged copies of this triple N gene construct were stably maintained in both Escherichia coli and Agrobacterium tumefaciens plasmids used during the cloning process, as well as in several generations of transgenic tobacco plants. A transgenic tobacco line was obtained that exhibited high levels of resistance to all three Tospoviruses, showing the possibility of producing transgenic plants with a broad resistance to Tospoviruses by introducing tandemly cloned viral N gene sequences. DNA analysis of this transgenic plant line shows that the multivirus resistance trait is confined to a single genetic locus, which is very convenient for further breeding purposes.
-
Possible causes of the emergence of tospovirus diseases.
Seminars in Virology, 1994Co-Authors: R. W. Goldbach, Dick PetersAbstract:Abstract Tomato spotted wilt virus, type species of the genus Tospovirus, ranks among the top ten of economically most important plant viruses. From 1980 on, a rapid emergence and geographic expansion of this, and some other Tospoviruses, has occurred. This contribution will provide evidence that the recent emergence of Tospoviruses, has two major causes. Firstly, these plant viruses have relatively recently evolved from the (animal-infecting) bunyaviruses and, secondly, one of their major vectors, the Western flower thrips, has dramatically expanded due to changes in agricultural practices and increase in transcontinental trading.