1
|
Shahriari Z, Su X, Zheng K, Zhang Z. Advances and Prospects of Virus-Resistant Breeding in Tomatoes. Int J Mol Sci 2023; 24:15448. [PMID: 37895127 PMCID: PMC10607384 DOI: 10.3390/ijms242015448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 10/15/2023] [Accepted: 10/16/2023] [Indexed: 10/29/2023] Open
Abstract
Plant viruses are the main pathogens which cause significant quality and yield losses in tomato crops. The important viruses that infect tomatoes worldwide belong to five genera: Begomovirus, Orthotospovirus, Tobamovirus, Potyvirus, and Crinivirus. Tomato resistance genes against viruses, including Ty gene resistance against begomoviruses, Sw gene resistance against orthotospoviruses, Tm gene resistance against tobamoviruses, and Pot 1 gene resistance against potyviruses, have been identified from wild germplasm and introduced into cultivated cultivars via hybrid breeding. However, these resistance genes mainly exhibit qualitative resistance mediated by single genes, which cannot protect against virus mutations, recombination, mixed-infection, or emerging viruses, thus posing a great challenge to tomato antiviral breeding. Based on the epidemic characteristics of tomato viruses, we propose that future studies on tomato virus resistance breeding should focus on rapidly, safely, and efficiently creating broad-spectrum germplasm materials resistant to multiple viruses. Accordingly, we summarized and analyzed the advantages and characteristics of the three tomato antiviral breeding strategies, including marker-assisted selection (MAS)-based hybrid breeding, RNA interference (RNAi)-based transgenic breeding, and CRISPR/Cas-based gene editing. Finally, we highlighted the challenges and provided suggestions for improving tomato antiviral breeding in the future using the three breeding strategies.
Collapse
Affiliation(s)
- Zolfaghar Shahriari
- Biotechnology and Germplasm Resources Research Institute, Yunnan Academy of Agricultural Sciences, Yunnan Seed Laboratory, 2238# Beijing Rd, Panlong District, Kunming 650205, China; (Z.S.); (X.S.)
- Crop and Horticultural Science Research Department, Fars Agricultural and Natural Resources Research and Education Center, Agricultural Research, Education and Extension Organization (AREEO), Shiraz 617-71555, Iran
| | - Xiaoxia Su
- Biotechnology and Germplasm Resources Research Institute, Yunnan Academy of Agricultural Sciences, Yunnan Seed Laboratory, 2238# Beijing Rd, Panlong District, Kunming 650205, China; (Z.S.); (X.S.)
| | - Kuanyu Zheng
- Biotechnology and Germplasm Resources Research Institute, Yunnan Academy of Agricultural Sciences, Yunnan Seed Laboratory, 2238# Beijing Rd, Panlong District, Kunming 650205, China; (Z.S.); (X.S.)
| | - Zhongkai Zhang
- Biotechnology and Germplasm Resources Research Institute, Yunnan Academy of Agricultural Sciences, Yunnan Seed Laboratory, 2238# Beijing Rd, Panlong District, Kunming 650205, China; (Z.S.); (X.S.)
| |
Collapse
|
2
|
Konakalla NC, Bag S, Deraniyagala AS, Culbreath AK, Pappu HR. Induction of Plant Resistance in Tobacco (Nicotiana tabacum) against Tomato Spotted Wilt Orthotospovirus through Foliar Application of dsRNA. Viruses 2021; 13:662. [PMID: 33921345 PMCID: PMC8069313 DOI: 10.3390/v13040662] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 04/09/2021] [Accepted: 04/09/2021] [Indexed: 02/07/2023] Open
Abstract
Thrips-transmitted tomato spotted wilt orthotospovirus (TSWV) continues to be a constraint to peanut, pepper, tobacco, and tomato production in Georgia and elsewhere. TSWV is being managed by an integrated disease management strategy that includes a combination of cultural practices, vector management, and growing virus-resistant varieties where available. We used a non-transgenic strategy to induce RNA interference (RNAi)-mediated resistance in tobacco (Nicotiana tabacum) plants against TSWV. Double-stranded RNA (dsRNA) molecules for the NSs (silencing suppressor) and N (nucleoprotein) genes were produced by a two-step PCR approach followed by in vitro transcription. When topically applied to tobacco leaves, both molecules elicited a resistance response. Host response to the treatments was measured by determining the time to symptom expression, and the level of resistance by absolute quantification of the virus. We also show the systemic movement of dsRNA_N from the inoculated leaves to younger, non-inoculated leaves. Post-application, viral siRNAs were detected for up to nine days in inoculated leaves and up to six days in non-inoculated leaves. The topical application of dsRNAs to induce RNAi represents an environmentally safe and efficient way to manage TSWV in tobacco crops and could be applicable to other TSWV-susceptible crops.
Collapse
Affiliation(s)
- Naga Charan Konakalla
- Department of Plant Pathology, University of Georgia, Tifton, GA 31793, USA; (N.C.K.); (A.S.D.); (A.K.C.)
- Department of Plant Protection Biology, Swedish University of Agricultural Sciences, 230 53 Alnarp, Sweden
| | - Sudeep Bag
- Department of Plant Pathology, University of Georgia, Tifton, GA 31793, USA; (N.C.K.); (A.S.D.); (A.K.C.)
| | | | - Albert K. Culbreath
- Department of Plant Pathology, University of Georgia, Tifton, GA 31793, USA; (N.C.K.); (A.S.D.); (A.K.C.)
| | - Hanu R. Pappu
- Department of Plant Pathology, Washington State University, Pullman, WA 99163, USA;
| |
Collapse
|
3
|
Tabein S, Jansen M, Noris E, Vaira AM, Marian D, Behjatnia SAA, Accotto GP, Miozzi L. The Induction of an Effective dsRNA-Mediated Resistance Against Tomato Spotted Wilt Virus by Exogenous Application of Double-Stranded RNA Largely Depends on the Selection of the Viral RNA Target Region. FRONTIERS IN PLANT SCIENCE 2020; 11:533338. [PMID: 33329620 PMCID: PMC7732615 DOI: 10.3389/fpls.2020.533338] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 11/09/2020] [Indexed: 06/02/2023]
Abstract
Tomato spotted wilt virus (TSWV) is a devastating plant pathogen, causing huge crop losses worldwide. Unfortunately, due to its wide host range and emergence of resistance breaking strains, its management is challenging. Up to now, resistance to TSWV infection based on RNA interference (RNAi) has been achieved only in transgenic plants expressing parts of the viral genome or artificial microRNAs targeting it. Exogenous application of double-stranded RNAs (dsRNAs) for inducing virus resistance in plants, namely RNAi-based vaccination, represents an attractive and promising alternative, already shown to be effective against different positive-sense RNA viruses and viroids. In the present study, the protection efficacy of exogenous application of dsRNAs targeting the nucleocapsid (N) or the movement protein (NSm) coding genes of the negative-sense RNA virus TSWV was evaluated in Nicotiana benthamiana as model plant and in tomato as economically important crop. Most of the plants treated with N-targeting dsRNAs, but not with NSm-targeting dsRNAs, remained asymptomatic until 40 (N. benthamiana) and 63 (tomato) dpi, while the remaining ones showed a significant delay in systemic symptoms appearance. The different efficacy of N- and NSm-targeting dsRNAs in protecting plants is discussed in the light of their processing, mobility and biological role. These results indicate that the RNAi-based vaccination is effective also against negative-sense RNA viruses but emphasize that the choice of the target viral sequence in designing RNAi-based vaccines is crucial for its success.
Collapse
Affiliation(s)
- Saeid Tabein
- Department of Plant Protection, Faculty of Agriculture, Shahid Chamran University of Ahvaz, Ahvaz, Iran
- Plant Virology Research Center, College of Agriculture, Shiraz University, Shiraz, Iran
- Institute for Sustainable Plant Protection, National Research Council of Italy, Turin, Italy
| | - Marco Jansen
- Institute for Sustainable Plant Protection, National Research Council of Italy, Turin, Italy
- Laboratory of Virology, Department of Plant Sciences, Wageningen University & Research, Wageningen, Netherlands
| | - Emanuela Noris
- Institute for Sustainable Plant Protection, National Research Council of Italy, Turin, Italy
| | - Anna Maria Vaira
- Institute for Sustainable Plant Protection, National Research Council of Italy, Turin, Italy
| | - Daniele Marian
- Institute for Sustainable Plant Protection, National Research Council of Italy, Turin, Italy
| | | | - Gian Paolo Accotto
- Institute for Sustainable Plant Protection, National Research Council of Italy, Turin, Italy
| | - Laura Miozzi
- Institute for Sustainable Plant Protection, National Research Council of Italy, Turin, Italy
| |
Collapse
|
4
|
Zhu M, van Grinsven IL, Kormelink R, Tao X. Paving the Way to Tospovirus Infection: Multilined Interplays with Plant Innate Immunity. ANNUAL REVIEW OF PHYTOPATHOLOGY 2019; 57:41-62. [PMID: 30893008 DOI: 10.1146/annurev-phyto-082718-100309] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Tospoviruses are among the most important plant pathogens and cause serious crop losses worldwide. Tospoviruses have evolved to smartly utilize the host cellular machinery to accomplish their life cycle. Plants mount two layers of defense to combat their invasion. The first one involves the activation of an antiviral RNA interference (RNAi) defense response. However, tospoviruses encode an RNA silencing suppressor that enables them to counteract antiviral RNAi. To further combat viral invasion, plants also employ intracellular innate immune receptors (e.g., Sw-5b and Tsw) to recognize different viral effectors (e.g., NSm and NSs). This leads to the triggering of a much more robust defense against tospoviruses called effector-triggered immunity (ETI). Tospoviruses have further evolved their effectors and can break Sw-5b-/Tsw-mediated resistance. The arms race between tospoviruses and both layers of innate immunity drives the coevolution of host defense and viral genes involved in counter defense. In this review, a state-of-the-art overview is presented on the tospoviral life cycle and the multilined interplays between tospoviruses and the distinct layers of defense.
Collapse
Affiliation(s)
- Min Zhu
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China;
| | - Irene Louise van Grinsven
- Laboratory of Virology, Department of Plant Sciences, Wageningen University, 6708PB Wageningen, The Netherlands
| | - Richard Kormelink
- Laboratory of Virology, Department of Plant Sciences, Wageningen University, 6708PB Wageningen, The Netherlands
| | - Xiaorong Tao
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China;
| |
Collapse
|
5
|
Prasad Babu K, Maligeppagol M, Asokan R, Krishna Reddy M. Screening of a multi-virus resistant RNAi construct in cowpea through transient vacuum infiltration method. Virusdisease 2019; 30:269-278. [PMID: 31179366 PMCID: PMC6531525 DOI: 10.1007/s13337-018-00509-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 12/29/2018] [Indexed: 11/24/2022] Open
Abstract
Plant viruses are the most devastating pathogens causing substantial economic losses in many crops. Current viral disease management relies on prophylactics, roguing and insect vector control, since in most crops resistant gene pools for resistance breeding are unavailable. RNA interference, a sequence dependent gene silencing mechanism holds great potential in imparting virus resistance. In this study, the efficacy of a RNAi gene construct developed against four viruses commonly infesting tomato and chilli viz., capsicum chlorosis virus, groundnut bud necrosis virus, cucumber mosaic virus and chilli veinal mottle virus was evaluated. A 3546 bp dsRNA-forming construct comprising sense-intron-antisense fragments in binary vector pBI121 (hpRNAi-MVR) was mobilized into Agrobacterium tumefaciens. Cowpea (Vigna unguiculata) was used as an indicator plant for GBNV agroinfiltration to evaluate the efficacy of hpRNAi-MVR construct in conferring GBNV resistance. The type of agroinfiltration, bacterial concentration and incubation-temperatures were optimized. Vacuum infiltration of three pulses of 20-30 s at 66.66 kPa were effective than syringe infiltration. Of the five Agrobacterial concentrations, OD600 0.5 was more efficient. Incubation temperature of 31 ± 1 °C was favorable for development of disease symptoms than 20 ± 1 °C and 26 ± 1 °C. ELISA revealed a 35% decline in viral load in hpRNAi-MVR infiltrated plants compared to vector control plants. Quantitative real time PCR results have shown a viral gene silencing to the extent of 930-990 folds in hpRNAi-MVR infiltrated plants compared to vector control. This approach is simple, rapid and efficient to screen the efficacy of RNAi constructs developed for the RNAi mediated plant virus management.
Collapse
Affiliation(s)
- K. Prasad Babu
- Division of Biotechnology, ICAR-Indian Institute of Horticultural Research, Hessaraghatta Lake Post, Hessaraghatta, Bangalore, 560089 India
- Department of Biotechnology, Centre for Post-graduate Studies, Jain University, Bangalore, India
| | - Manamohan Maligeppagol
- Division of Biotechnology, ICAR-Indian Institute of Horticultural Research, Hessaraghatta Lake Post, Hessaraghatta, Bangalore, 560089 India
| | - R. Asokan
- Division of Biotechnology, ICAR-Indian Institute of Horticultural Research, Hessaraghatta Lake Post, Hessaraghatta, Bangalore, 560089 India
| | - M. Krishna Reddy
- Division of Plant Pathology, ICAR-Indian Institute of Horticultural Research, Hessaraghatta Lake Post, Hessaraghatta, Bangalore, 560089 India
| |
Collapse
|
6
|
Carbonell A, López C, Daròs JA. Fast-Forward Identification of Highly Effective Artificial Small RNAs Against Different Tomato spotted wilt virus Isolates. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2019; 32:142-156. [PMID: 30070616 DOI: 10.1094/mpmi-05-18-0117-ta] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Artificial small RNAs (sRNAs), including artificial microRNAs (amiRNAs) and synthetic trans-acting small interfering RNAs (syn-tasiRNAs), are used to silence viral RNAs and confer antiviral resistance in plants. Here, the combined use of recent high-throughput methods for generating artificial sRNA constructs and the Tomato spotted wilt virus (TSWV)-Nicotiana benthamiana pathosystem allowed for the simple and rapid identification of amiRNAs with high anti-TSWV activity. A comparative analysis between the most effective amiRNA construct and a syn-tasiRNA construct including the four most effective amiRNA sequences showed that both were highly effective against two different TSWV isolates. These results highlight the usefulness of this high-throughput methodology for the fast-forward identification of artificial sRNAs with high antiviral activity prior to time-consuming generation of stably transformed plants.
Collapse
Affiliation(s)
- Alberto Carbonell
- 1 Instituto de Biología Molecular y Celular de Plantas (Consejo Superior de Investigaciones Científicas-Universitat Politècnica de València), 46022 Valencia, Spain; and
| | - Carmelo López
- 2 Instituto de Conservación y Mejora de la Agrodiversidad Valenciana, Universitat Politècnica de València, 46022 Valencia, Spain
| | - José-Antonio Daròs
- 1 Instituto de Biología Molecular y Celular de Plantas (Consejo Superior de Investigaciones Científicas-Universitat Politècnica de València), 46022 Valencia, Spain; and
| |
Collapse
|
7
|
Mitter N, Zhai Y, Bai AX, Chua K, Eid S, Constantin M, Mitchell R, Pappu HR. Evaluation and identification of candidate genes for artificial microRNA-mediated resistance to tomato spotted wilt virus. Virus Res 2016; 211:151-8. [PMID: 26454192 DOI: 10.1016/j.virusres.2015.10.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Revised: 09/29/2015] [Accepted: 10/01/2015] [Indexed: 01/12/2023]
Abstract
Tomato spotted wilt virus (TSWV) is an economically important viral pathogen of a wide range of field and horticultural crops. We developed an artificial microRNA (amiRNA) strategy against TSWV, targeting the nucleoprotein (N) and silencing suppressor (NSs) genes. The amiRNA constructs replaced the natural miRNA in a shortened Arabidopsis 173-nucleotide (nt) miR159a precursor backbone (athmiR159a) without the stem base extending beyond the miR/miR* duplex. Further, each amiRNA was modified to contain a mismatch (wobble) sequence at nucleotide position 12 and 13 on the complementary strand amiRNA*, mimicking the endogenous miR159a sequence structure. Transient expression in Nicotiana benthamiana demonstrated that the introduction of a wobble sequence did not alter amiRNA expression levels. Following challenge inoculation with TSWV, plants expressing N-specific amiRNAs with or without the wobble remained asymptomatic and were negative for TSWV by ELISA. In contrast, plants expressing the NSs-specific amiRNAs were symptomatic and accumulated high levels of TSWV. Similar findings were obtained in stably transformed Nicotiana tabacum plants. Our results show that a shortened 173-nt athmiR159a backbone is sufficient to express amiRNAs and that the presence of mismatch at position 12-13 does not influence amiRNA expression or conferring of resistance. We also show that selection of target gene and positional effect are critical in amiRNA-based approach for introducing resistance. These findings open the possibility of employing the amiRNA approach for broad-spectrum resistance to tospoviruses as well as other viruses.
Collapse
Affiliation(s)
- Neena Mitter
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St. Lucia, QLD, Australia
| | - Ying Zhai
- Department of Plant Pathology, Washington State University, Pullman, WA, USA
| | - Anh Xu Bai
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St. Lucia, QLD, Australia
| | - Keith Chua
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St. Lucia, QLD, Australia
| | - Sahar Eid
- Department of Plant Pathology, Washington State University, Pullman, WA, USA
| | - Myrna Constantin
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St. Lucia, QLD, Australia
| | - Roger Mitchell
- Queensland Agricultural Biotechnology Centre, University of Queensland, Ritchie Building, Research Road, QLD 4072, Australia
| | - Hanu R Pappu
- Department of Plant Pathology, Washington State University, Pullman, WA, USA.
| |
Collapse
|
8
|
Yazhisai U, Rajagopalan PA, Raja JAJ, Chen TC, Yeh SD. Untranslatable tospoviral NSs fragment coupled with L conserved region enhances transgenic resistance against the homologous virus and a serologically unrelated tospovirus. Transgenic Res 2015; 24:635-49. [PMID: 25721329 DOI: 10.1007/s11248-015-9865-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 02/03/2015] [Indexed: 10/23/2022]
Abstract
Tospoviruses cause severe damages to important crops worldwide. In this study, Nicotiana benthamiana transgenic lines carrying individual untranslatable constructs comprised of the conserved region of the L gene (denoted as L), the 5' half of NSs coding sequence (NSs) or the antisense fragment of whole N coding sequence (N) of Watermelon silver mottle virus (WSMoV), individually or in combination, were generated. A total of 15-17 transgenic N. benthamiana lines carrying individual transgenes were evaluated against WSMoV and the serologically unrelated Tomato spotted wilt virus (TSWV). Among lines carrying single or chimeric transgenes, the level of resistance ranged from susceptible to completely resistant against WSMoV. From the lines carrying individual transgenes and highly resistant to WSMoV (56-63% of lines assayed), 30% of the L lines (3/10 lines assayed) and 11% of NSs lines (1/9 lines assayed) were highly resistant against TSWV. The chimeric transgenes provided higher degrees of resistance against WSMoV (80-88%), and the NSs fragment showed an additive effect to enhance the resistance to TSWV. Particularly, the chimeric transgenes with the triple combination of fragments, namely L/NSs/N or HpL/NSs/N (a hairpin construct), provided a higher degree of resistance (both 50%, with 7/14 lines assayed) against TSWV. Our results indicate that the untranslatable NSs fragment is able to enhance the transgenic resistance conferred by the L conserved region. The better performance of L/NSs/N and HpL/NSs/N in transgenic N. benthamiana lines suggests their potential usefulness in generating high levels of enhanced transgenic resistance against serologically unrelated tospoviruses in agronomic crops.
Collapse
Affiliation(s)
- Uthaman Yazhisai
- Department of Plant Pathology, College of Agriculture and Natural Resource, National Chung Hsing University, 250-Kuo-Kuang Road, Taichung, 40227, Taiwan, ROC
| | | | | | | | | |
Collapse
|
9
|
Abstract
Transgenic resistance to plant viruses is an important technology for control of plant virus infection, which has been demonstrated for many model systems, as well as for the most important plant viruses, in terms of the costs of crop losses to disease, and also for many other plant viruses infecting various fruits and vegetables. Different approaches have been used over the last 28 years to confer resistance, to ascertain whether particular genes or RNAs are more efficient at generating resistance, and to take advantage of advances in the biology of RNA interference to generate more efficient and environmentally safer, novel "resistance genes." The approaches used have been based on expression of various viral proteins (mostly capsid protein but also replicase proteins, movement proteins, and to a much lesser extent, other viral proteins), RNAs [sense RNAs (translatable or not), antisense RNAs, satellite RNAs, defective-interfering RNAs, hairpin RNAs, and artificial microRNAs], nonviral genes (nucleases, antiviral inhibitors, and plantibodies), and host-derived resistance genes (dominant resistance genes and recessive resistance genes), and various factors involved in host defense responses. This review examines the above range of approaches used, the viruses that were tested, and the host species that have been examined for resistance, in many cases describing differences in results that were obtained for various systems developed in the last 20 years. We hope this compilation of experiences will aid those who are seeking to use this technology to provide resistance in yet other crops, where nature has not provided such.
Collapse
Affiliation(s)
| | - Peter Palukaitis
- Department of Horticultural Sciences, Seoul Women's University, Seoul, Republic of Korea.
| |
Collapse
|
10
|
Catoni M, Lucioli A, Doblas-Ibáñez P, Accotto GP, Vaira AM. From immunity to susceptibility: virus resistance induced in tomato by a silenced transgene is lost as TGS overcomes PTGS. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2013; 75:941-953. [PMID: 23738576 DOI: 10.1111/tpj.12253] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Revised: 05/20/2013] [Accepted: 05/31/2013] [Indexed: 06/02/2023]
Abstract
Tomato line 30.4 was obtained engineering the nucleocapsid (N) gene of tomato spotted wilt virus into plant genome, and immunity to tomato spotted wilt virus infection of its self-pollinated homozygous progeny was observed. Despite the presence of a high amount of transgenic transcripts, transgenic proteins have not been detected, suggesting a mechanism of resistance mediated by RNA. In the present study, we identify post-transcriptional gene silencing as the main mechanism of resistance, which is able to spread systemically through grafting, and show that the line 30.4 resistant plants produce both 24 and 21-22 nt N-gene specific siRNA classes. The transgenic locus in chromosome 4 shows complex multiple insertions of four T-DNA copies in various orientations, all with 3' end deletions in the terminator and part of the N gene. However, for three of them, polyadenylated transcripts are produced, due to flanking tomato genome sequences acting as alternative terminators. Interestingly, starting at the fifth generation after the transformation event, some individual plants show a tomato spotted wilt virus-susceptible phenotype. The change is associated with the disappearance of transgene-specific transcripts and siRNAs, and with hyper-methylation of the transgene, which proceeds gradually through the generations. Once it reaches a critical threshold, the shift from post-transcriptional gene silencing to transcriptional silencing of the transgene eliminates the previously well established virus resistance.
Collapse
Affiliation(s)
- Marco Catoni
- Istituto di Virologia Vegetale, Consiglio Nazionale delle Ricerche, Strada delle Cacce 73, 10135, Turin, Italy.
| | | | | | | | | |
Collapse
|
11
|
Prins M, Laimer M, Noris E, Schubert J, Wassenegger M, Tepfer M. Strategies for antiviral resistance in transgenic plants. MOLECULAR PLANT PATHOLOGY 2008; 9:73-83. [PMID: 18705886 PMCID: PMC6640351 DOI: 10.1111/j.1364-3703.2007.00447.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Genetic engineering offers a means of incorporating new virus resistance traits into existing desirable plant cultivars. The initial attempts to create transgenes conferring virus resistance were based on the pathogen-derived resistance concept. The expression of the viral coat protein gene in transgenic plants was shown to induce protective effects similar to classical cross protection, and was therefore distinguished as 'coat-protein-mediated' protection. Since then, a large variety of viral sequences encoding structural and non-structural proteins were shown to confer resistance. Subsequently, non-coding viral RNA was shown to be a potential trigger for virus resistance in transgenic plants, which led to the discovery of a novel innate resistance in plants, RNA silencing. Apart from the majority of pathogen-derived resistance strategies, alternative strategies involving virus-specific antibodies have been successfully applied. In a separate section, efforts to combat viroids in transgenic plants are highlighted. In a final summarizing section, the potential risks involved in the introduction of transgenic crops and the specifics of the approaches used will be discussed.
Collapse
Affiliation(s)
- Marcel Prins
- Laboratory of Virology, Wageningen University, Binnenhaven 11, 6709 PD, Wageningen, The Netherlands.
| | | | | | | | | | | |
Collapse
|
12
|
Schwach F, Adam G, Heinze C. 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. MOLECULAR PLANT PATHOLOGY 2004; 5:309-316. [PMID: 20565598 DOI: 10.1111/j.1364-3703.2004.00229.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
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, due to the presence of an in-frame start codon in the PPV leader, was detected. This modified N protein was present in nucleocore and virion preparations and appears to confer resistance by interfering with systemic spread of the virus in the aerial parts of the transgenic plants, while not having an effect on primary replication.
Collapse
Affiliation(s)
- Frank Schwach
- Institute of Applied Botany, University of Hamburg, Ohnhorststr. 18, 22609 Hamburg, Germany
| | | | | |
Collapse
|
13
|
Yang H, Ozias-Akins P, Culbreath AK, Gorbet DW, Weeks JR, Mandal B, Pappu HR. Field Evaluation of Tomato spotted wilt virus Resistance in Transgenic Peanut (Arachis hypogaea). PLANT DISEASE 2004; 88:259-264. [PMID: 30812357 DOI: 10.1094/pdis.2004.88.3.259] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Spotted wilt, caused by Tomato spotted wilt virus (TSWV), is a devastating disease of many crops including peanut (Arachis hypogaea). Because the virus has a broad host range and is spread by ubiquitous thrips, disease management by traditional means is difficult. Developing new peanut cultivars with resistance to TSWV presents a significant challenge since existing genetic resistance in peanut germ plasm is limited. A genetic engineering approach appears to have great potential for resistance enhancement to TSWV. Transgenic peanut progenies that expressed the nucleocapsid protein of TSWV were subjected to natural infection of the virus under field conditions during the growing seasons of 1999 and 2000 in Tifton, GA, and in three locations (Tifton, GA, Marianna, FL, and Headland, AL) in 2001. Significantly lower incidence of spotted wilt was observed for the transgenic progeny in comparison to the nontransgenic checks in the field (in multiple years and locations) as well as during challenge inoculation under controlled environmental conditions. This transgenic event could potentially be used in a traditional breeding program to enhance host resistance.
Collapse
Affiliation(s)
- H Yang
- Department of Horticulture, The University of Georgia Tifton Campus, Tifton, GA 31793-0748
| | - P Ozias-Akins
- Department of Horticulture, The University of Georgia Tifton Campus, Tifton, GA 31793-0748
| | - A K Culbreath
- Department of Plant Pathology, The University of Georgia Tifton Campus, Tifton, GA 31793-0748
| | - D W Gorbet
- North Florida Research and Education Center, 3925 Highway 71, Marianna, FL 32446
| | - J R Weeks
- Wiregrass Experiment Station, Auburn University, Headland, AL 36345
| | - B Mandal
- Department of Plant Pathology, The University of Georgia Tifton Campus, Tifton, GA 31793-0748
| | - H R Pappu
- Department of Plant Pathology, The University of Georgia Tifton Campus, Tifton, GA 31793-0748
| |
Collapse
|
14
|
Hoffmann K, Qiu WP, Moyer JW. Overcoming host- and pathogen-mediated resistance in tomato and tobacco maps to the M RNA of Tomato spotted wilt virus. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2001; 14:242-9. [PMID: 11204788 DOI: 10.1094/mpmi.2001.14.2.242] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
A viral genetic system was used to map the determinants of the ability of Tomato spotted wilt virus (TSWV) to overcome the R gene (Sw-5) in tomato and the resistance conferred by the nucleocapsid gene of TSWV (N gene) in tobacco. A complete set of reassortant genotypes was generated from TSWV isolates A and D. TSWV-A was able to overcome the Sw-5 gene in tomato and the TSWV N gene in tobacco, whereas TSWV-D was repressed by both forms of resistance. The ability to overcome both forms of resistance was associated with the M RNA segment of TSWV-A (M(A)). Overcoming the Sw-5 gene was linked solely to the presence of M(A), and the ability of M(A) to overcome the TSWV N gene was modified by the L RNA and the S RNA of TSWV-A, which is consistent with previous reports that suggest that the nucleocapsid gene is not the primary determinant for overcoming the nucleocapsid-mediated resistance. Sequence analysis of the M RNA segment of TSWV-A, -D, and the type isolate BR-01 revealed multiple differences in the coding and noncoding regions, which prevented identification of the resistance-breaking nucleotide sequences.
Collapse
Affiliation(s)
- K Hoffmann
- Department of Virology, DLO Research Institute for Plant Protection (IPO-DLO), Wageningen, The Netherlands
| | | | | |
Collapse
|
15
|
Herrero S, Culbreath AK, Csinos AS, Pappu HR, Rufty RC, Daub ME. Nucleocapsid Gene-Mediated Transgenic Resistance Provides Protection Against Tomato spotted wilt virus Epidemics in the Field. PHYTOPATHOLOGY 2000; 90:139-147. [PMID: 18944602 DOI: 10.1094/phyto.2000.90.2.139] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
ABSTRACT Transformation of plants with the nucleocapsid (N) gene of Tomato spotted wilt tospovirus (TSWV) provides resistance to disease development; however, information is lacking on the response of plants to natural inoculum in the field. Three tobacco cultivars were transformed with the N gene of a dahlia isolate of TSWV (TSWV-D), and plants were evaluated over several generations in the greenhouse. The resistant phenotype was more frequently observed in 'Burley 21' than in 'KY-14' or 'K-326', but highly resistant 'Burley 21' transgenic lines were resistant to only 44% of the heterologous TSWV isolates tested. Advanced generation (R(3) and R(4)) transgenic resistant lines of 'Burley 21' and a 'K-326' F(1) hybrid containing the N genes of two TSWV isolates were evaluated in the field near Tifton, GA, where TSWV is endemic. Disease development was monitored by symptom expression and enzyme-linked immunosorbent assay (ELISA) analysis. Whereas incidence of TSWV infection in 'Burley 21' susceptible controls was 20% in 1996 and 62% in 1997, the mean incidence in transgenic lines was reduced to 4 and 31%, respectively. Three transgenic 'Burley 21' lines were identified that had significantly lower incidence of disease than susceptible controls over the two years of the study. In addition, the rate of disease increase at the onset of the 1997 epidemic was reduced for all the 'Burley 21' transgenic lines compared with the susceptible controls. The 'K-326' F(1) hybrid was as susceptible as the 'K-326' nontransformed control. ELISA analysis demonstrated that symptomless plants from the most resistant 'Burley 21' transgenic lines accumulated detectable nucleocapsid protein, whereas symptomless plants from more susceptible lines did not. We conclude that transgenic resistance to TSWV is effective in reducing incidence of the disease in the field, and that accumulation of transgene protein may be important in broad-spectrum resistance.
Collapse
|
16
|
Inserting the Nucleoprotein Gene of Tomato Spotted Wilt Virus in Different Plant Species, and Screening for Virus Resistance. ACTA ACUST UNITED AC 2000. [DOI: 10.1016/s0168-7972(00)80023-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
|
17
|
Qiu W, Moyer JW. Tomato Spotted Wilt Tospovirus Adapts to the TSWV N Gene-Derived Resistance by Genome Reassortment. PHYTOPATHOLOGY 1999; 89:575-82. [PMID: 18944693 DOI: 10.1094/phyto.1999.89.7.575] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
ABSTRACT Pathogen- and host-derived resistance have been shown to suppress infection by many plant viruses. Tomato spotted wilt tospovirus (TSWV) is among these systems; however, it has easily overcome nearly all host resistance genes and has recently been shown to overcome resistance mediated by the TSWV N gene. To better understand the resistance-breaking mechanisms, we have chosen TSWV N gene-derived resistance (TNDR) as a model to study how plant viruses defeat resistance genes. A defined viral population of isolates TSWV-D and TSWV-10, both suppressed by TNDR, was subjected to TNDR selection by serial passage in an N-gene transgenic plant. The genotype analysis demonstrated that the mixed viral population was driven to form a specific reassortant, L(10)M(10)S(D), in the presence of TNDR selection, but remained as a heterogeneous mixture in the absence of the selection. A genotype assay of 120 local lesion isolates from the first, fourth, and seventh transfers confirmed the shift of genomic composition. Further analysis demonstrated that the individual L(10), M(10), and S(D) RNA segments were each selected independently in response to TNDR selection rather than to a mutation or recombination event. Following the seventh transfer on the N-gene transgenic plants, TSWV S RNA remained essentially identical to the S RNA from TSWV-D, indicating that no intermolecular recombination occurred between the two S RNAs from TSWV-10 and TSWV-D nor with the transferred N gene. These results support the hypothesis that TSWV utilizes genome reassortment to adapt to new host genotypes rapidly and that elements from two or more segments of the genome are involved in suppression of the resistance reaction.
Collapse
|
18
|
Malpica CA, Cervera MT, Simoens C, Van Montagu M. Engineering resistance against viral diseases in plants. Subcell Biochem 1998; 29:287-320. [PMID: 9594651 DOI: 10.1007/978-1-4899-1707-2_9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- C A Malpica
- Department of Genetics, Flanders Interuniversity Institute for Biotechnology (VIB), Universiteit Gent, Belgium
| | | | | | | |
Collapse
|
19
|
Sherman JM, Moyer JW, Daub ME. Tomato Spotted Wilt Virus Resistance in Chrysanthemum Expressing the Viral Nucleocapsid Gene. PLANT DISEASE 1998; 82:407-414. [PMID: 30856889 DOI: 10.1094/pdis.1998.82.4.407] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Three tomato spotted wilt virus (TSWV) nucleocapsid (N) gene constructs were employed for Agrobacterium-mediated transformation of chrysanthemum (Dendranthema grandiflora) cv. Polaris. These constructs contained either a full-length N gene (pTSWVN+), a full-length N gene encoding a truncated N protein (pTSWVNt), or an antisense version of the full-length N gene (pTSWVN-), all derived from a dahlia isolate of TSWV (TSWV-D). Initial resistance screens were conducted on cuttings made from 152 pTSWVN+, 37 pTSWVNt, and 47 pTSWVN- transformed plants employing a highly virulent, heterologous strain of TSWV (TSWV-GB) isolated from chrysanthemum and vectored by thrips. This screening served to eliminate the majority of TSWV-susceptible transgenic lines. More rigorous resistance tests with three rounds of mechanical inoculation with TSWV-GB identified one pTSWVNt and two pTSWVN- transformed lines that exhibited a total lack of systemic symptoms and no virus accumulation. Six other lines, including some pTSWVN+, exhibited a lack of one or more of the destructive necrotic TSWV symptoms (stem canker and apical bud death) and a delay in symptom expression. Both sense and antisense constructs, therefore, were found to be effective at yielding TSWV resistance in chrysanthemum. Molecular analysis revealed that the highly TSWV-resistant pTSWVNt line had no detectable levels of N protein. All three resistant lines had low levels of N gene transcript and at least three transgene insertion sites within their genomes, although susceptible lines often had a similar number of insertion sites. The generation of Polaris lines resistant to TSWV transmitted either mechanically or by thrips represents the first time a major ornamental crop has been genetically engineered for disease resistance.
Collapse
Affiliation(s)
- John M Sherman
- Department of Plant Pathology, Box 7616, North Carolina State University, Raleigh 27695-7616
| | - James W Moyer
- Department of Plant Pathology, Box 7616, North Carolina State University, Raleigh 27695-7616
| | - Margaret E Daub
- Department of Plant Pathology, Box 7616, North Carolina State University, Raleigh 27695-7616
| |
Collapse
|
20
|
Prins M, Goldbach R. The emerging problem of tospovirus infection and nonconventional methods of control. Trends Microbiol 1998; 6:31-5. [PMID: 9481822 DOI: 10.1016/s0966-842x(97)01173-6] [Citation(s) in RCA: 113] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The emergence of tospoviruses as a significant problem in the cultivation of many crops around the world makes it vital to develop strategies to restrain these viruses. So far, only a few natural resistance genes suitable for introduction into plant breeding programs have been identified, prompting the exploitation of alternative ways of introducing virus resistance into crop plants, such as genetic modifications.
Collapse
Affiliation(s)
- M Prins
- Dept of Virology, Wageningen Agricultural University, The Netherlands
| | | |
Collapse
|
21
|
Application of recombinant DNA technology to plant protection: molecular approaches to engineering virus resistance in crop plants. World J Microbiol Biotechnol 1995; 11:426-37. [DOI: 10.1007/bf00364618] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
22
|
Abstract
This review describes the proposed mechanism(s) of classical virus cross-protection in plants, followed by those suggested for coat protein-mediated resistance (CP-mediated resistance). Although both have common features, cross-protection is thought to be a complex response caused by the replication and expression of the entire viral genome, whereas the resistance conferred by the expression of a virus coat protein gene is more limited. The term genetically engineered cross-protection is frequently used because in many cases the phenotype of resistance mimics that of cross-protection. However, CP-mediated resistance, although a narrow term, more accurately describes the resistance that results from the expression of a virus CP gene in transgenic plants.
Collapse
Affiliation(s)
- A F Hackland
- Department of Microbiology, University of Cape Town, Rondebosch, South Africa
| | | | | |
Collapse
|
23
|
Pang SZ, Slightom JL, Gonsalves D. Different mechanisms protect transgenic tobacco against tomato spotted wilt and impatiens necrotic spot Tospoviruses. Nat Biotechnol 1993; 11:819-24. [PMID: 7763861 DOI: 10.1038/nbt0793-819] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
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.
Collapse
Affiliation(s)
- S Z Pang
- Department of Plant Pathology, Cornell University, NYSAES, Geneva 14456
| | | | | |
Collapse
|
24
|
Wilson TM. Strategies to protect crop plants against viruses: pathogen-derived resistance blossoms. Proc Natl Acad Sci U S A 1993; 90:3134-41. [PMID: 8475051 PMCID: PMC46254 DOI: 10.1073/pnas.90.8.3134] [Citation(s) in RCA: 165] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Since 1986, the ability to confer resistance against an otherwise devastating virus by introducing a single pathogen-derived or virus-targeted sequence into the DNA of a potential host plant has had a marked influence on much of the research effort, focus, and short-term objectives of plant virologists throughout the world. The vast literature on coat protein-mediated protection, for example, attests to our fascination for unraveling fundamental molecular mechanism(s), our (vain) search for a unifying hypothesis, our pragmatic interest in commercially exploitable opportunities for crop protection, and our ingenuity in manipulating transgene constructions to broaden their utility and reduce real or perceived environmental risk issues. Other single dominant, pathogen-derived plant resistance genes have recently been discovered from a wide variety of viruses and are operative in an ever-increasing range of plant species. Additional candidates seem limited only by the effort invested in experimentation and by our ingenuity and imagination. This review attempts to consider, in a critical way, the current state of the art, some exceptions, and some proposed rules. The final impression, from all the case evidence considered, is that normal virus replication requires a subtle blend of host- and virus-coded proteins, present in critical relative concentrations and at specific times and places. Any unregulated superimposition of interfering protein or nucleic acid species can, therefore, result in an apparently virus-resistant plant phenotype.
Collapse
Affiliation(s)
- T M Wilson
- Department of Virology, Scottish Crop Research Institute, Invergowrie, Dundee, United Kingdom
| |
Collapse
|
25
|
de Haan P, Gielen JJ, Prins M, Wijkamp IG, van Schepen A, Peters D, van Grinsven MQ, Goldbach R. Characterization of RNA-mediated resistance to tomato spotted wilt virus in transgenic tobacco plants. Nat Biotechnol 1992; 10:1133-7. [PMID: 1368791 DOI: 10.1038/nbt1092-1133] [Citation(s) in RCA: 89] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Recently high levels of protection against tomato spotted wilt virus (TSWV), a negative-strand RNA virus infecting plants, have been obtained by transforming tobacco with viral nucleoprotein (N) gene sequences. Here we demonstrate that this protection is primarily due to the presence of N gene transcripts in the cells of transgenic plants, and hence appears to be RNA-mediated. Further, transgenic tobacco plants are only protected to isolates and strains of TSWV and not to other tospoviruses that share considerable nucleotide sequence homology in their N genes to TSWV. In addition to being protected after mechanical inoculation, the transgenic tobacco plants are also resistant to inoculation using viruliferous thrips, i.e. Frankliniella occidentalis (Perg.), one of the most important natural vector species.
Collapse
Affiliation(s)
- P de Haan
- Department of Virology, Agricultural University Wageningen, The Netherlands
| | | | | | | | | | | | | | | |
Collapse
|