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Nishiguchi M, Ali ME, Kaya T, Kobayashi K. Plant virus disease control by vaccination and transgenic approaches: Current status and perspective. PLANT RNA VIRUSES 2023:373-424. [DOI: 10.1016/b978-0-323-95339-9.00028-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
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2
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H. El-Sappah A, Qi S, A. Soaud S, Huang Q, M. Saleh A, A. S. Abourehab M, Wan L, Cheng GT, Liu J, Ihtisham M, Noor Z, Rouf Mir R, Zhao X, Yan K, Abbas M, Li J. Natural resistance of tomato plants to Tomato yellow leaf curl virus. FRONTIERS IN PLANT SCIENCE 2022; 13:1081549. [PMID: 36600922 PMCID: PMC9807178 DOI: 10.3389/fpls.2022.1081549] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 11/28/2022] [Indexed: 06/17/2023]
Abstract
Tomato yellow leaf curl virus (TYLCV) is one of the most harmful afflictions in the world that affects tomato growth and production. Six regular antagonistic genes (Ty-1, Ty-2, Ty-3, Ty-4, ty-5, and Ty-6) have been transferred from wild germplasms to commercial cultivars as TYLCV protections. With Ty-1 serving as an appropriate source of TYLCV resistance, only Ty-1, Ty-2, and Ty-3 displayed substantial levels of opposition in a few strains. It has been possible to clone three TYLCV opposition genes (Ty-1/Ty-3, Ty-2, and ty-5) that target three antiviral safety mechanisms. However, it significantly impacts obtaining permanent resistance to TYLCV, trying to maintain opposition whenever possible, and spreading opposition globally. Utilizing novel methods, such as using resistance genes and identifying new resistance resources, protects against TYLCV in tomato production. To facilitate the breeders make an informed decision and testing methods for TYLCV blockage, this study highlights the portrayal of typical obstruction genes, common opposition sources, and subatomic indicators. The main goal is to provide a fictitious starting point for the identification and application of resistance genes as well as the maturation of tomato varieties that are TYLCV-resistant.
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Affiliation(s)
- Ahmed H. El-Sappah
- Faculty of Agriculture, Forestry and Food Engineering, Yibin University, Yibin, Sichuan, China
- Genetics Department, Faculty of Agriculture, Zagazig University, Zagazig, Egypt
| | - Shiming Qi
- College of Agriculture and Ecological Engineering, Hexi University, Zhangye, China
| | - Salma A. Soaud
- Genetics Department, Faculty of Agriculture, Zagazig University, Zagazig, Egypt
| | - Qiulan Huang
- Faculty of Agriculture, Forestry and Food Engineering, Yibin University, Yibin, Sichuan, China
| | - Alaa M. Saleh
- Laboratory Medicine Department, Faculty of Applied Medical Sciences, Umm Al-Qura University, Makkah, Saudi Arabia
| | | | - Lingyun Wan
- Key Laboratory of Guangxi for High-quality Formation and Utilization of Dao-di Herbs, Guangxi Botanical Garden of Medicinal Plants, Nanning, China
| | - Guo-ting Cheng
- Shaanxi Key Laboratory of Chinese Jujube, College of Life Science, Yan’an University, Yan’an, China
| | - Jingyi Liu
- College of Horticulture, Northwest A&F University, Yangling, China
| | - Muhammad Ihtisham
- Faculty of Agriculture, Forestry and Food Engineering, Yibin University, Yibin, Sichuan, China
| | - Zarqa Noor
- School of Chemical Engineering Beijing Institute of Technology, Beijing, China
| | - Reyazul Rouf Mir
- Division of Genetics and Plant Breeding, Faculty of Agriculture (FoA), SKUAST–Kashmir, Sopore, India
| | - Xin Zhao
- Faculty of Agriculture, Forestry and Food Engineering, Yibin University, Yibin, Sichuan, China
| | - Kuan Yan
- Faculty of Agriculture, Forestry and Food Engineering, Yibin University, Yibin, Sichuan, China
| | - Manzar Abbas
- Faculty of Agriculture, Forestry and Food Engineering, Yibin University, Yibin, Sichuan, China
| | - Jia Li
- Faculty of Agriculture, Forestry and Food Engineering, Yibin University, Yibin, Sichuan, China
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More P, Agarwal P, Anand A, Sanan-Mishra N, Agarwal PK. Artificial miRNA mediated resistance in tobacco against Jatropha leaf curl Gujarat virus by targeting RNA silencing suppressors. Sci Rep 2021; 11:890. [PMID: 33441589 PMCID: PMC7806619 DOI: 10.1038/s41598-020-79134-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 12/03/2020] [Indexed: 11/09/2022] Open
Abstract
The leaf curl disease of Jatropha caused by geminiviruses results in heavy economic losses. In the present study, we report the identification of a new strain of a Jatropha leaf curl Gujarat virus (JLCuGV), which encodes six ORFs with each one having RNA silencing suppressor activity. Therefore, three artificial microRNAs (amiRNAs; C1/C4, C2/C3 and V1/V2) were designed employing overlapping regions, each targeting two ORFs of JLCuGV genomic DNA and transformed in tobacco. The C1/C4 and C2/C3 amiRNA transgenics were resistant while V1/V2 amiRNA transgenics were tolerant against JLCuGV. The relative level of amiRNA inversely related to viral load indicating a correlation with disease resistance. The assessment of photosynthetic parameters suggests that the transgenics perform significantly better in response to JLCuGV infiltration as compared to wild type (WT). The metabolite contents were not altered remarkably in amiRNA transgenics, but sugar metabolism and tricarboxylic acid (TCA) cycle showed noticeable changes in WT on virus infiltration. The overall higher methylation and demethylation observed in amiRNA transgenics correlated with decreased JLCuGV accumulation. This study demonstrates that amiRNA transgenics showed enhanced resistance to JLCuGV while efficiently maintaining normalcy in their photosynthesis and metabolic pathways as well as homeostasis in the methylation patterns.
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Affiliation(s)
- Prashant More
- Plant Omics Division, CSIR-Central Salt and Marine Chemicals Research Institute (CSIR-CSMCRI), Council of Scientific and Industrial Research (CSIR), Gijubhai Badheka Marg, 364 002, Bhavnagar, Gujarat, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Parinita Agarwal
- Plant Omics Division, CSIR-Central Salt and Marine Chemicals Research Institute (CSIR-CSMCRI), Council of Scientific and Industrial Research (CSIR), Gijubhai Badheka Marg, 364 002, Bhavnagar, Gujarat, India.
| | - Abhishek Anand
- Plant RNAi Biology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, 110 067, India
| | - Neeti Sanan-Mishra
- Plant RNAi Biology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, 110 067, India
| | - Pradeep K Agarwal
- Plant Omics Division, CSIR-Central Salt and Marine Chemicals Research Institute (CSIR-CSMCRI), Council of Scientific and Industrial Research (CSIR), Gijubhai Badheka Marg, 364 002, Bhavnagar, Gujarat, India.
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India.
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Díaz-Pendón JA, Sánchez-Campos S, Fortes IM, Moriones E. Tomato Yellow Leaf Curl Sardinia Virus, a Begomovirus Species Evolving by Mutation and Recombination: A Challenge for Virus Control. Viruses 2019; 11:E45. [PMID: 30634476 PMCID: PMC6356960 DOI: 10.3390/v11010045] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 12/28/2018] [Accepted: 01/08/2019] [Indexed: 12/12/2022] Open
Abstract
The tomato leaf curl disease (TYLCD) is associated with infections of several species of begomoviruses (genus Begomovirus, family Geminiviridae) and causes severe damage to tomatoes throughout tropical and sub-tropical regions of the world. Among others, the Tomato yellow leaf curl Sardinia virus (TYLCSV) species causes damage in the Mediterranean Basin since early outbreaks occurred. Nevertheless, scarce information is available about the diversity of TYLCSV. Here, we study this aspect based on the sequence information accessible in databases. Isolates of two taxonomically differentiated TYLCSV strains can be found in natural epidemics. Their evolution is mostly associated with mutation combined with selection and random genetic drift and also with inter-species recombination which is frequent in begomoviruses. Moreover, a novel putative inter-strain recombinant is reported. Although no significantly new biological behaviour was observed for this latter recombinant, its occurrence supports that as shown for other related begomoviruses, recombination continues to play a central role in the evolution of TYLCD-associated viruses and the dynamism of their populations. The confrontation of resistant tomatoes with isolates of different TYLCD-associated viruses including the novel recombinant demonstrates the existence of a variable virus x plant genotype interaction. This has already been observed for other TYLCD-associated viruses and is a challenge for the control of their impact on tomato production.
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Affiliation(s)
- Juan A Díaz-Pendón
- Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora" (IHSM-UMA-CSIC), Consejo Superior de Investigaciones Científicas, Estación Experimental "La Mayora". Av. Dr. Wienberg s/n, Algarrobo-Costa, 29750 Málaga, Spain.
| | - Sonia Sánchez-Campos
- Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora" (IHSM-UMA-CSIC), Consejo Superior de Investigaciones Científicas, Estación Experimental "La Mayora". Av. Dr. Wienberg s/n, Algarrobo-Costa, 29750 Málaga, Spain.
| | - Isabel María Fortes
- Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora" (IHSM-UMA-CSIC), Consejo Superior de Investigaciones Científicas, Estación Experimental "La Mayora". Av. Dr. Wienberg s/n, Algarrobo-Costa, 29750 Málaga, Spain.
| | - Enrique Moriones
- Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora" (IHSM-UMA-CSIC), Consejo Superior de Investigaciones Científicas, Estación Experimental "La Mayora". Av. Dr. Wienberg s/n, Algarrobo-Costa, 29750 Málaga, Spain.
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Ruhel R, Chakraborty S. Multifunctional roles of geminivirus encoded replication initiator protein. Virusdisease 2018; 30:66-73. [PMID: 31143833 DOI: 10.1007/s13337-018-0458-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 05/28/2018] [Indexed: 12/31/2022] Open
Abstract
Geminivirus infection has been a threat to cultivation worldwide by causing huge losses to the crop. The single-stranded DNA genome of a geminivirus possesses a limited coding potential and many of the open reading frames (ORFs) are overlapping. Out of 5-7 ORFs that a geminivirus genome codes for, the AC1 ORF encodes for the replication initiator protein (Rep) which is involved in the replication of virus within the infected plant cell. Rep is the only viral protein absolutely required for the in planta viral replication. Across different genera of the Geminiviridae family, the AC1 ORF exhibits a high degree of sequence conservation thus it has been used as an effective target for developing broad spectrum resistance against the invading geminiviruses. This multifunctional protein is required for initiation, elongation as well as termination of the viral replication process. Rep is also involved in stimulation of viral transcription. In addition, it also functions as suppressor of gene silencing and is involved in the process of transcription by regulating the expression of certain viral genes. Rep protein also interacts with few viral proteins such as coat protein, replication enhancer protein and with several host factors involved in different pathways and processes for its replication and efficient infection. This review will summarise our current understanding about the role of this early viral protein in viral propagation as well as in establishment of pathogenesis in a permissive host.
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Affiliation(s)
- Rajrani Ruhel
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067 India
| | - Supriya Chakraborty
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067 India
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Jeevalatha A, Siddappa S, Kumar A, Kaundal P, Guleria A, Sharma S, Nagesh M, Singh BP. An insight into differentially regulated genes in resistant and susceptible genotypes of potato in response to tomato leaf curl New Delhi virus-[potato] infection. Virus Res 2017; 232:22-33. [PMID: 28115198 DOI: 10.1016/j.virusres.2017.01.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Revised: 01/04/2017] [Accepted: 01/08/2017] [Indexed: 12/13/2022]
Abstract
Apical leaf curl disease, caused by tomato leaf curl New Delhi virus-[potato] (ToLCNDV-[potato]) is one of the most important viral diseases of potato in India. Genetic resistance source for ToLCNDV in potato is not identified so far. However, the cultivar Kufri Bahar is known to show lowest seed degeneration even under high vector levels. Hence, microarray analysis was performed to identify differentially regulated genes during ToLCNDV-[potato] infection in a resistant (Kufri Bahar) and a susceptible cultivar (Kufri Pukhraj). Under artificial inoculation conditions, in Kufri Pukhraj, symptom expressions started at 15days after inoculation (DAI) and then progressed to severe symptoms, whereas no or only very mild symptoms were observed in Kufri Bahar up to 35 DAI. Correspondingly, qPCR assay indicated a high viral load in Kufri Pukhraj and a very low viral load in Kufri Bahar. Microarray analysis showed that a total of 1111 genes and 2588 genes were differentially regulated (|log2 (Fold Change)|>2) in Kufri Bahar and Kufri Pukhraj, respectively, following ToLCNDV-[potato] infection. Gene ontology and mapman analyses revealed that these altered transcripts were involved in various biological & metabolic processes. Several genes with unknown functions were 5 to 100 fold expressed after virus infection and further experiments are necessary to ascertain their role in disease resistance or susceptibility. This study gives an insight into differentially regulated genes in response to ToLCNDV-[potato] infection in resistant and susceptible cultivars and could serve as the basis for the development of new strategies for disease management.
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Affiliation(s)
- Arjunan Jeevalatha
- ICAR-Central Potato Research Institute, Shimla 171 001, Himachal Pradesh, India.
| | - Sundaresha Siddappa
- ICAR-Central Potato Research Institute, Shimla 171 001, Himachal Pradesh, India
| | - Ashwani Kumar
- ICAR-Central Potato Research Institute, Shimla 171 001, Himachal Pradesh, India
| | - Priyanka Kaundal
- ICAR-Central Potato Research Institute, Shimla 171 001, Himachal Pradesh, India
| | - Anupama Guleria
- ICAR-Central Potato Research Institute, Shimla 171 001, Himachal Pradesh, India
| | - Sanjeev Sharma
- ICAR-Central Potato Research Institute, Shimla 171 001, Himachal Pradesh, India
| | - Mandadi Nagesh
- ICAR-Central Potato Research Institute, Shimla 171 001, Himachal Pradesh, India
| | - Bir Pal Singh
- ICAR-Central Potato Research Institute, Shimla 171 001, Himachal Pradesh, India
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7
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Lucioli A, Perla C, Berardi A, Gatti F, Spanò L, Tavazza M. Transcriptomics of tomato plants infected with TYLCSV or expressing the central TYLCSV Rep protein domain uncover changes impacting pathogen response and senescence. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2016; 103:61-70. [PMID: 26966899 DOI: 10.1016/j.plaphy.2016.02.034] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 01/26/2016] [Accepted: 02/25/2016] [Indexed: 05/20/2023]
Abstract
To establish a successful infection viruses need to overcome plant innate immune responses and redirect host gene expression for their multiplication and diffusion. Tomato yellow leaf curl Sardinia virus (TYLCSV) is a geminivirus, which causes significant economic losses in tomato. The multifunctional replication associated geminivirus protein (Rep) has an important role during viral infection. In particular, the Rep central domain spanning from aa 120 to 180 is known to interact with viral and host factors. In this study, we used long serial analysis of gene expression to analyse the transcriptional profiles of transgenic tomato plants expressing the first 210 amino acids of TYLCSV Rep (Rep210) and TYLCSV-infected wild-type tomato plants (Wt-Ty). Also, we compared these profiles with those of transgenic Rep130 tomatoes. Comparison of Wt-Ty and Rep210 libraries with the wild-type one identified 118 and 203 differentially expressed genes (DEGs), respectively. Importantly, 55% of Wt-Ty DEGs were in common with Rep210, and no ones showed opposite expression. Conversely, a negligible overlap was found between Rep130 DEGs and Wt-Ty and Rep210 ones. TYLCSV- and Rep210-repressed genes, but not induced ones, overlapped with the leaf senescence process. Interestingly, TYLCSV upregulates expression of genes involved in the negative regulation of programmed cell death (PCD), several of which were also regulated by the abscisic acid. Rep210 upregulated genes related to defence response, immune system processes and negative regulation of PCD. Collectively, our results support a model in which the Rep central domain has a pivotal role in redirecting host plant gene expression.
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Affiliation(s)
- Alessandra Lucioli
- Agenzia nazionale per le nuove tecnologie, l'energia e lo sviluppo economico sostenibile (ENEA), C.R. Casaccia, Via Anguillarese 301, 00123 Rome, Italy
| | - Carlo Perla
- Agenzia nazionale per le nuove tecnologie, l'energia e lo sviluppo economico sostenibile (ENEA), C.R. Casaccia, Via Anguillarese 301, 00123 Rome, Italy; Università degli Studi dell'Aquila, Department of Physical and Chemical Sciences, Via Giovanni di Vincenzo, 67100 L'Aquila, Italy
| | - Alessandra Berardi
- Agenzia nazionale per le nuove tecnologie, l'energia e lo sviluppo economico sostenibile (ENEA), C.R. Casaccia, Via Anguillarese 301, 00123 Rome, Italy
| | - Francesca Gatti
- Agenzia nazionale per le nuove tecnologie, l'energia e lo sviluppo economico sostenibile (ENEA), C.R. Casaccia, Via Anguillarese 301, 00123 Rome, Italy
| | - Laura Spanò
- Università degli Studi dell'Aquila, Department of Physical and Chemical Sciences, Via Giovanni di Vincenzo, 67100 L'Aquila, Italy
| | - Mario Tavazza
- Agenzia nazionale per le nuove tecnologie, l'energia e lo sviluppo economico sostenibile (ENEA), C.R. Casaccia, Via Anguillarese 301, 00123 Rome, Italy.
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Leibman D, Prakash S, Wolf D, Zelcer A, Anfoka G, Haviv S, Brumin M, Gaba V, Arazi T, Lapidot M, Gal-On A. Immunity to tomato yellow leaf curl virus in transgenic tomato is associated with accumulation of transgene small RNA. Arch Virol 2015; 160:2727-39. [PMID: 26255053 DOI: 10.1007/s00705-015-2551-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 07/20/2015] [Indexed: 12/11/2022]
Abstract
Gene silencing is a natural defense response of plants against invading RNA and DNA viruses. The RNA post-transcriptional silencing system has been commonly utilized to generate transgenic crop plants that are "immune" to plant virus infection. Here, we applied this approach against the devastating DNA virus tomato yellow leaf curl virus (TYLCV) in its host tomato (Solanum lycopersicum L.). To generate broad resistance to a number of different TYLCV viruses, three conserved sequences (the intergenic region [NCR], V1-V2 and C1-C2 genes) from the genome of the severe virus (TYLCV) were synthesized as a single insert and cloned into a hairpin configuration in a binary vector, which was used to transform TYLCV-susceptible tomato plants. Eight of 28 independent transgenic tomato lines exhibited immunity to TYLCV-Is and to TYLCV-Mld, but not to tomato yellow leaf curl Sardinia virus, which shares relatively low sequence homology with the transgene. In addition, a marker-free (nptII-deleted) transgenic tomato line was generated for the first time by Agrobacterium-mediated transformation without antibiotic selection, followed by screening of 1180 regenerated shoots by whitefly-mediated TYLCV inoculation. Resistant lines showed a high level of transgene-siRNA (t-siRNA) accumulation (22% of total small RNA) with dominant sizes of 21 nt (73%) and 22 nt (22%). The t-siRNA displayed hot-spot distribution ("peaks") along the transgene, with different distribution patterns than the viral-siRNA peaks observed in TYLCV-infected tomato. A grafting experiment demonstrated the mobility of 0.04% of the t-siRNA from transgenic rootstock to non-transformed scion, even though scion resistance against TYLCV was not achieved.
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Affiliation(s)
- Diana Leibman
- Department of Plant Pathology and Weed Science, ARO, Volcani Center, 50250, Bet Dagan, Israel
| | - Shanmugam Prakash
- Department of Plant Pathology and Weed Science, ARO, Volcani Center, 50250, Bet Dagan, Israel
| | - Dalia Wolf
- Department of Vegetable Research, ARO, Volcani Center, 50250, Bet Dagan, Israel
| | - Aaron Zelcer
- Department of Vegetable Research, ARO, Volcani Center, 50250, Bet Dagan, Israel
| | - Ghandi Anfoka
- Department of Biotechnology, Al-Balqa' Applied University, Al-Salt, 19117, Jordan
| | - Sabrina Haviv
- Department of Plant Pathology and Weed Science, ARO, Volcani Center, 50250, Bet Dagan, Israel
| | - Marina Brumin
- Department of Plant Pathology and Weed Science, ARO, Volcani Center, 50250, Bet Dagan, Israel
| | - Victor Gaba
- Department of Plant Pathology and Weed Science, ARO, Volcani Center, 50250, Bet Dagan, Israel
| | - Tzahi Arazi
- Department of Ornamental Horticulture, ARO, Volcani Center, 50250, Bet Dagan, Israel
| | - Moshe Lapidot
- Department of Vegetable Research, ARO, Volcani Center, 50250, Bet Dagan, Israel
| | - Amit Gal-On
- Department of Plant Pathology and Weed Science, ARO, Volcani Center, 50250, Bet Dagan, Israel.
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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.
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Affiliation(s)
| | - Peter Palukaitis
- Department of Horticultural Sciences, Seoul Women's University, Seoul, Republic of Korea.
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Ammara UE, Mansoor S, Saeed M, Amin I, Briddon RW, Al-Sadi AM. RNA interference-based resistance in transgenic tomato plants against Tomato yellow leaf curl virus-Oman (TYLCV-OM) and its associated betasatellite. Virol J 2015; 12:38. [PMID: 25890080 PMCID: PMC4359554 DOI: 10.1186/s12985-015-0263-y] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 02/10/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Tomato yellow leaf curl virus (TYLCV), a monopartite begomovirus (family Geminiviridae) is responsible for heavy yield losses for tomato production around the globe. In Oman at least five distinct begomoviruses cause disease in tomato, including TYLCV. Unusually, TYLCV infections in Oman are sometimes associated with a betasatellite (Tomato leaf curl betasatellite [ToLCB]; a symptom modulating satellite). RNA interference (RNAi) can be used to develop resistance against begomoviruses at either the transcriptional or post-transcriptional levels. RESULTS A hairpin RNAi (hpRNAi) construct to express double-stranded RNA homologous to sequences of the intergenic region, coat protein gene, V2 gene and replication-associated gene of Tomato yellow leaf curl virus-Oman (TYLCV-OM) was produced. Initially, transient expression of the hpRNAi construct at the site of virus inoculation was shown to reduce the number of plants developing symptoms when inoculated with either TYLCV-OM or TYLCV-OM with ToLCB-OM to Nicotiana benthamiana or tomato. Solanum lycopersicum L. cv. Pusa Ruby was transformed with the hpRNAi construct and nine confirmed transgenic lines were obtained and challenged with TYLCV-OM and ToLCB-OM by Agrobacterium-mediated inoculation. For all but one line, for which all plants remained symptomless, inoculation with TYLCV-OM led to a proportion (≤25%) of tomato plants developing symptoms of infection. For inoculation with TYLCV-OM and ToLCB-OM all lines showed a proportion of plants (≤45%) symptomatic. However, for all infected transgenic plants the symptoms were milder and virus titre in plants was lower than in infected non-transgenic tomato plants. CONCLUSIONS These results show that RNAi can be used to develop resistance against geminiviruses in tomato. The resistance in this case is not immunity but does reduce the severity of infections and virus titer. Also, the betasatellite may compromise resistance, increasing the proportion of plants which ultimately show symptoms.
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Affiliation(s)
- Um e Ammara
- Department of Crop Sciences, College of Agriculture and Marine Sciences, Sultan Qaboos University, P.O. Box-34, 123, Al-Khod, Oman.
| | - Shahid Mansoor
- Agricultural Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), P O Box 577, Jhang Road, Faisalabad, Pakistan.
| | - Muhammad Saeed
- Agricultural Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), P O Box 577, Jhang Road, Faisalabad, Pakistan.
| | - Imran Amin
- Agricultural Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), P O Box 577, Jhang Road, Faisalabad, Pakistan.
| | - Rob W Briddon
- Agricultural Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), P O Box 577, Jhang Road, Faisalabad, Pakistan.
| | - Abdullah Mohammed Al-Sadi
- Department of Crop Sciences, College of Agriculture and Marine Sciences, Sultan Qaboos University, P.O. Box-34, 123, Al-Khod, Oman.
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11
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Abstract
RNA interference (RNAi) has emerged as a leading technology in designing genetically modified crops engineered to resist viral infection. The last decades have seen the development of a large number of crops whose inherent posttranscriptional gene silencing mechanism has been exploited to target essential viral genes through the production of dsRNA that triggers an endogenous RNA-induced silencing complex (RISC), leading to gene silencing in susceptible viruses conferring them with resistance even before the onset of infection. Selection and breeding events have allowed for establishing this highly important agronomic trait in diverse crops. With improved techniques and the availability of new data on genetic diversity among several viruses, significant progress is being made in engineering plants using RNAi with the release of a number of commercially available crops. Biosafety concerns with respect to consumption of RNAi crops, while relevant, have been addressed, given the fact that experimental evidence using miRNAs associated with the crops shows that they do not pose any health risk to humans and animals.
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Affiliation(s)
- Abdulrazak B Ibrahim
- Embrapa Recursos Genéticos e Biotecnologia, LEG, PqEB W5 Norte, 70770-917, Brasília, DF, Brazil
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12
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Di Nicola E, Tavazza M, Lucioli A, Salandri L, Ilardi V. Robust RNA silencing-mediated resistance to Plum pox virus under variable abiotic and biotic conditions. MOLECULAR PLANT PATHOLOGY 2014; 15:841-7. [PMID: 25346969 PMCID: PMC6638643 DOI: 10.1111/mpp.12132] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Some abiotic and biotic conditions are known to have a negative impact on post-transcriptional gene silencing (PTGS), thus representing a potential concern for the production of stable engineered virus resistance traits. However, depending on the strategy followed to achieve PTGS of the transgene, different responses to external conditions can be expected. In the present study, we utilized the Nicotiana benthamiana–Plum pox virus (PPV) pathosystem to evaluate in detail the stability of intron-hairpin(ihp)-mediated virus resistance under conditions known to adversely affect PTGS. The ihp plants grown at low or high temperatures were fully resistant to multiple PPV challenges, different PPV inoculum concentrations and even to a PPV isolate differing from the ihp construct by more than 28% at the nucleotide level. In addition, infections of ihp plants with viruses belonging to Cucumovirus, Potyvirus or Tombusvirus, all known to affect PTGS at different steps, were not able to defeat PPV resistance. Low temperatures did not affect the accumulation of transgenic small interfering RNAs (siRNAs), whereas a clear increase in the amount of siRNAs was observed during infections sustained by Cucumber mosaic virus and Potato virus Y. Our results show that the above stress factors do not represent an important concern for the production,through ihp-PTGS technology, of transgenic plants having robust virus resistance traits.
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Yong Chung H, Lacatus G, Sunter G. Geminivirus AL2 protein induces expression of, and interacts with, a calmodulin-like gene, an endogenous regulator of gene silencing. Virology 2014; 460-461:108-18. [PMID: 25010276 DOI: 10.1016/j.virol.2014.04.034] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Revised: 02/27/2014] [Accepted: 04/12/2014] [Indexed: 11/29/2022]
Abstract
RNA silencing is an innate cellular response involved in antiviral defense. Arabidopsis calmodulin-like protein 39 (At-rgsCaM) is related to known regulators of RNA silencing in tomato and Nicotiana tabacum. Geminivirus AL2 protein functions to suppress post-transcriptional and transcriptional gene silencing, possibly through induction of an endogenous regulator. In support of this, the At-rgsCaM promoter responds to Tomato golden mosaic virus (TGMV) AL2 in protoplasts and geminivirus infection increases rgsCaM expression in Arabidopsis and Nicotiana benthamiana. Further, over-expression of rgsCaM leads to increased susceptibility to infection, as a consequence of increased viral DNA loads. It has been shown that rgsCaM may target silencing suppressors of RNA viruses for degradation via the autophagy pathway. This interaction occurs within the cytoplasm, but AL2 interacts with rgsCaM in the nucleus. It is tempting to speculate that AL2 may act to sequester rgsCaM in the nucleus to prevent targeting of AL2 for degradation.
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Affiliation(s)
- Ho Yong Chung
- Department of Biology, The University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249, USA
| | - Gabriela Lacatus
- Scripps Health/Hematology/Oncology Division, 15004 Innovation Dr., San Diego, CA 92128, USA
| | - Garry Sunter
- Department of Biology, The University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249, USA.
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Lucioli A, Berardi A, Gatti F, Tavazza R, Pizzichini D, Tavazza M. Tomato yellow leaf curl Sardinia virus-resistant tomato plants expressing the multifunctional N-terminal domain of the replication-associated protein show transcriptional changes resembling stress-related responses. MOLECULAR PLANT PATHOLOGY 2014; 15:31-43. [PMID: 23910556 PMCID: PMC6638761 DOI: 10.1111/mpp.12063] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The N-terminal domain (amino acids 1-130) of the replication-associated protein (Rep130 ) of Tomato yellow leaf curl Sardinia virus (TYLCSV) retains the ability of full-length Rep to localize to the nucleus and to down-regulate C1 transcription when ectopically expressed in plants, both functions being required to inhibit homologous viral replication. In this study, we analysed the effect of Rep130 expression on virus resistance and the plant transcriptome in the natural and agronomically important host species of TYLCSV, Solanum lycopersicum. Tomato plants accumulating high levels of Rep130 were generated and proved to be resistant to TYLCSV. Using an in vitro assay, we showed that plant-expressed Rep130 also retains the catalytic activity of Rep, thus supporting the notion that this protein domain is fully functional. Interestingly, Rep130 -expressing tomatoes were characterized by an altered transcriptional profile resembling stress-related responses. Notably, the serine-type protease inhibitor (Ser-PI) category was over-represented among the 20 up-regulated genes. The involvement of Rep130 in the alteration of host mRNA steady-state levels was confirmed using a distinct set of virus-resistant transgenic tomato plants expressing the same TYLCSV Rep130 , but from a different, synthetic, gene. Eight genes were found to be up-regulated in both types of transgenic tomato and two encoded Ser-PIs. Four of these eight genes were also up-regulated in TYLCSV-infected wild-type tomato plants. Implications with regard to the ability of this Rep domain to interfere with viral infections and to alter the host transcriptome are discussed.
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Affiliation(s)
- Alessandra Lucioli
- Agenzia Nazionale per le Nuove Tecnologie, l'Energia e l'Ambiente (ENEA), UTAGRI-INN, C.R. Casaccia, Via Anguillarese 301, 00123, Rome, Italy
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15
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Medina-Hernández D, Rivera-Bustamante RF, Tenllado F, Holguín-Peña RJ. Effects and effectiveness of two RNAi constructs for resistance to Pepper golden mosaic virus in Nicotiana benthamiana plants. Viruses 2013; 5:2931-45. [PMID: 24287597 PMCID: PMC3967154 DOI: 10.3390/v5122931] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 11/14/2013] [Accepted: 11/20/2013] [Indexed: 01/11/2023] Open
Abstract
ToChLPV and PepGMV are Begomoviruses that have adapted to a wide host range and are able to cause major diseases in agronomic crops. We analyzed the efficacy of induced resistance to PepGMV in Nicotiana benthamiana plants with two constructs: one construct with homologous sequences derived from PepGMV, and the other construct with heterologous sequences derived from ToChLPV. Plants protected with the heterologous construct showed an efficacy to decrease the severity of symptoms of 45%, while plants protected with the homologous construct showed an efficacy of 80%. Plants protected with the heterologous construct showed a reduction of incidence of 42.86%, while the reduction of incidence in plants protected with the homologous construct was 57.15%. The efficacy to decrease viral load was 95.6% in plants protected with the heterologous construct, and 99.56% in plants protected with the homologous construct. We found, in both constructs, up-regulated key components of the RNAi pathway. This demonstrates that the efficacy of the constructs was due to the activation of the gene silencing mechanism, and is reflected in the decrease of viral genome copies, as well as in recovery phenotype. We present evidence that both constructs are functional and can efficiently induce transient resistance against PepGMV infections. This observation guarantees a further exploration as a strategy to control complex Begomovirus diseases in the field.
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Affiliation(s)
- Diana Medina-Hernández
- Laboratorio de Fitopatología, Centro de Investigaciones Biológicas del Noroeste, Instituto Politécnico Nacional 195, Col. Playa Palo de Santa Rita, La Paz, Baja California Sur, 23096, Mexico; E-Mails: (R.J.H.P.); (D.M.H.)
| | - Rafael Francisco Rivera-Bustamante
- Departamento de Ingeniería Genética, Centro de Investigación y de Estudios Avanzados del IPN, Unidad Irapuato, Km. 9.6 Libramiento Norte, Irapuato, Guanajuato, 36821, Mexico; E-Mail: (R.F.R.B.)
| | - Francisco Tenllado
- Departamento de Biología Medioambiental, Centro de Investigaciones Biológicas, Ramiro de Maeztu 9, Madrid, 28040, Spain; E-Mail: (F.T.)
| | - Ramón Jaime Holguín-Peña
- Laboratorio de Fitopatología, Centro de Investigaciones Biológicas del Noroeste, Instituto Politécnico Nacional 195, Col. Playa Palo de Santa Rita, La Paz, Baja California Sur, 23096, Mexico; E-Mails: (R.J.H.P.); (D.M.H.)
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16
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Miozzi L, Pantaleo V, Burgyán J, Accotto GP, Noris E. Analysis of small RNAs derived from tomato yellow leaf curl Sardinia virus reveals a cross reaction between the major viral hotspot and the plant host genome. Virus Res 2013; 178:287-96. [PMID: 24091361 DOI: 10.1016/j.virusres.2013.09.029] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 09/18/2013] [Accepted: 09/19/2013] [Indexed: 10/26/2022]
Abstract
RNA silencing is a defense mechanism exploited by plants against viruses. Upon infection, viral genomes and their transcripts are processed by Dicer-like (DCL) ribonucleases into viral small interfering RNAs (vsRNAs) of 21-24 nucleotides that further guide silencing of viral transcripts. To get an insight into the molecular interaction between tomato and the monopartite phloem-limited begomovirus tomato yellow leaf curl Sardinia virus (TYLCSV), a pathogen inducing a devastating disease of tomato in the Mediterranean region, we characterized by deep sequencing the vsRNA population in virus-infected tomato plants, using a Solexa/Illumina platform. TYLCSV-sRNAs spanned the entire viral genome but were discontinuously distributed throughout it, with a prevalence from the transcribed regions. TYLCSV-sRNAs were mainly 21-22 nucleotides in length and their polarity was asymmetrically distributed along the genome. The most abundant vsRNAs originated from a narrow region overlapping the Rep/C4 genes and from a broader region including the end of the V2 and the beginning of the coat protein genes. Deep sequencing results were validated by different hybridization techniques. Comparisons with the data available on vsRNAs for other begomoviruses highlighted both similarities and differences. Host-derived RNA species cross-reacting with a portion of the viral genome corresponding to the most abundant vsRNAs hotspot were detected. Bioinformatics analyses were carried out to investigate the nature of these host molecules.
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Affiliation(s)
- Laura Miozzi
- Istituto di Virologia Vegetale, CNR, Strada delle Cacce 73, 101035 Torino, Italy
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17
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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.
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Affiliation(s)
- Marco Catoni
- Istituto di Virologia Vegetale, Consiglio Nazionale delle Ricerche, Strada delle Cacce 73, 10135, Turin, Italy.
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18
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Aragão FJ, Nogueira EO, Tinoco MLP, Faria JC. Molecular characterization of the first commercial transgenic common bean immune to the Bean golden mosaic virus. J Biotechnol 2013; 166:42-50. [DOI: 10.1016/j.jbiotec.2013.04.009] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 04/18/2013] [Accepted: 04/22/2013] [Indexed: 11/29/2022]
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19
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Lin CY, Tsai WS, Ku HM, Jan FJ. Evaluation of DNA fragments covering the entire genome of a monopartite begomovirus for induction of viral resistance in transgenic plants via gene silencing. Transgenic Res 2012; 21:231-41. [PMID: 21597979 DOI: 10.1007/s11248-011-9523-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2010] [Accepted: 05/05/2011] [Indexed: 10/18/2022]
Abstract
Tomato-infecting begomoviruses, a member of whitefly-transmitted geminivirus, cause the most devastating virus disease complex of cultivated tomato crops in the tropical and subtropical regions. Numerous strategies have been used to engineer crops for their resistance to geminiviruses. However, nearly all have concentrated on engineering the replication-associated gene (Rep), but not on a comprehensive evaluation of the entire virus genome. In this study, Tomato leaf curl Taiwan virus (ToLCTWV), a predominant tomato-infecting begomovirus in Taiwan, was subjected to the investigation of the viral gene fragments conferring resistance to geminiviruses in transgenic plants. Ten transgenic constructs covering the entire ToLCTWV genome were fused to a silencer DNA, the middle half of N gene of Tomato spot wilt virus (TSWV), to induce gene silencing and these constructs were transformed into Nicotiana benthamiana plants. Two constructs derived from IRC1 (intergenic region flanked with 5' end Rep) and C2 (partial C2 ORF) were able to render resistance to ToLCTWV in transgenic N. benthamiana plants. Transgenic plants transformed with two other constructs, C2C3 (overlapping region of C2 and C3 ORFs) and Rep2 (3' end of the C1 ORF), significantly delayed the symptom development. Detection of siRNA confirmed that the mechanism of resistance was via gene silencing. This study demonstrated for the first time the screening of the entire genome of a monopartite begomovirus to discover viral DNA fragments that might be suitable for conferring virus resistance, and which could be potential candidates for developing transgenic plants with durable and broad-spectrum resistance to a DNA virus via a gene silencing approach.
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MESH Headings
- DNA, Viral/genetics
- DNA, Viral/metabolism
- Disease Resistance
- Gene Fusion
- Gene Silencing
- Genome, Viral
- Open Reading Frames
- Plant Diseases/immunology
- Plant Diseases/virology
- Plants, Genetically Modified/genetics
- Plants, Genetically Modified/immunology
- Plants, Genetically Modified/metabolism
- Plants, Genetically Modified/virology
- RNA, Plant/genetics
- RNA, Plant/metabolism
- RNA, Small Interfering/genetics
- RNA, Small Interfering/metabolism
- Taiwan
- Nicotiana/genetics
- Nicotiana/immunology
- Nicotiana/metabolism
- Nicotiana/virology
- Tospovirus/genetics
- Tospovirus/immunology
- Tospovirus/metabolism
- Tospovirus/pathogenicity
- Transformation, Genetic
- Transgenes
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Affiliation(s)
- Ching-Yi Lin
- Department of Plant Pathology, National Chung Hsing University, Taichung, 402, Taiwan
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20
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Sunitha S, Marian D, Hohn B, Veluthambi K. Antibegomoviral activity of the agrobacterial virulence protein VirE2. Virus Genes 2011; 43:445-53. [PMID: 21842234 DOI: 10.1007/s11262-011-0654-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2011] [Accepted: 08/01/2011] [Indexed: 10/17/2022]
Abstract
Mungbean yellow mosaic geminivirus (MYMV) causes severe yellow mosaic disease in blackgram, mungbean, Frenchbean, pigeonpea, soybean and mothbean. We attempted to induce resistance against this virus using the transcriptional activator protein gene deleted in the C-terminal activation domain (TrAP-∆AD) and Agrobacterium tumefaciens virE2. MYMV is known to replicate in agroinoculated tobacco leaf discs. Three transgenic tobacco plants which harboured a truncated MYMV transcriptional activator protein gene and two tobacco plants transformed with the octopine type A. tumefaciens virE2 gene were agroinoculated with an A. tumefaciens strain which harboured the partial dimers of both DNA A and DNA B of MYMV. The level of viral DNA accumulation in leaf discs of transgenic plants correlated inversely to the level of the MYMV TrAP-∆AD transcript. Two VirE2-transgenic plants, which complemented tumorigenesis of a virE2 mutant A. tumefaciens strain, effectively reduced MYMV DNA accumulation in the leaf disc agroinoculation assay.
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Affiliation(s)
- Sukumaran Sunitha
- Department of Plant Biotechnology, Madurai Kamaraj University, Madurai, India
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21
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Nahid N, Amin I, Briddon RW, Mansoor S. RNA interference-based resistance against a legume mastrevirus. Virol J 2011; 8:499. [PMID: 22047503 PMCID: PMC3214926 DOI: 10.1186/1743-422x-8-499] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Accepted: 11/02/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND RNA interference (RNAi) is a homology-dependant gene silencing mechanism and has been widely used to engineer resistance in plants against RNA viruses. However, its usefulness in delivering resistance against plant DNA viruses belonging to family Geminiviridae is still being debated. Although the RNAi approach has been shown, using a transient assay, to be useful in countering monocotyledonous plant-infecting geminiviruses of the genus Mastrevirus, it has yet to be investigated as a means of delivering resistance to dicot-infecting mastreviruses. Chickpea chlorotic dwarf Pakistan virus (CpCDPKV) is a legume-infecting mastrevirus that affects chickpea and other leguminous crops in Pakistan. RESULTS Here a hairpin (hp)RNAi construct containing sequences encompassing part of replication-associated protein gene, intergenic region and part of the movement protein gene of CpCDPKV under the control of the Cauliflower mosaic virus 35S promoter has been produced and stably transformed into Nicotiana benthamiana. Plants harboring the hairpin construct were challenged with CpCDPKV. All non-transgenic N. benthamiana plants developed symptoms of CpCDPKV infection within two weeks post-inoculation. In contrast, none of the inoculated transgenic plants showed symptoms of infection and no viral DNA could be detected by Southern hybridization. A real-time quantitative PCR analysis identified very low-level accumulation of viral DNA in the inoculated transgenic plants. CONCLUSIONS The results presented show that the RNAi-based resistance strategy is useful in protecting plants from a dicot-infecting mastrevirus. The very low levels of virus detected in plant tissue of transgenic plants distal to the inoculation site suggest that virus movement and/or viral replication was impaired leading to plants that showed no discernible signs of virus infection.
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Affiliation(s)
- Nazia Nahid
- Agricultural Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), P O Box 577, Jhang Road, Faisalabad, Pakistan
| | - Imran Amin
- Agricultural Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), P O Box 577, Jhang Road, Faisalabad, Pakistan
| | - Rob W Briddon
- Agricultural Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), P O Box 577, Jhang Road, Faisalabad, Pakistan
| | - Shahid Mansoor
- Agricultural Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), P O Box 577, Jhang Road, Faisalabad, Pakistan
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Sardo L, Wege C, Kober S, Kocher C, Accotto GP, Noris E. RNA viruses and their silencing suppressors boost Abutilon mosaic virus, but not the Old World Tomato yellow leaf curl Sardinia virus. Virus Res 2011; 161:170-80. [PMID: 21843560 DOI: 10.1016/j.virusres.2011.07.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Revised: 07/26/2011] [Accepted: 07/27/2011] [Indexed: 11/19/2022]
Abstract
Mixed viral infections can induce different changes in symptom development, genome accumulation and tissue tropism. These issues were investigated for two phloem-limited begomoviruses, Abutilon mosaic virus (AbMV) and Tomato yellow leaf curl Sardinia virus (TYLCSV) in Nicotiana benthamiana plants doubly infected by either the potyvirus Cowpea aphid-borne mosaic virus (CABMV) or the tombusvirus Artichoke mottled crinkle virus (AMCV). Both RNA viruses induced an increase of the amount of AbMV, led to its occasional egress from the phloem and induced symptom aggravation, while the amount and tissue tropism of TYLCSV were almost unaffected. In transgenic plants expressing the silencing suppressors of CABMV (HC-Pro) or AMCV (P19), AbMV was supported to a much lesser extent than in the mixed infections, with the effect of CABMV HC-Pro being superior to that of AMCV P19. Neither of the silencing suppressors influenced TYLCSV accumulation. These results demonstrate that begomoviruses differentially respond to the invasion of other viruses and to silencing suppression.
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Affiliation(s)
- Luca Sardo
- Istituto di Virologia Vegetale, CNR, Strada delle Cacce 73, I-10135 Torino, Italy
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23
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Simón-Mateo C, García JA. Antiviral strategies in plants based on RNA silencing. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2011; 1809:722-31. [PMID: 21652000 DOI: 10.1016/j.bbagrm.2011.05.011] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Revised: 05/17/2011] [Accepted: 05/18/2011] [Indexed: 01/25/2023]
Abstract
One of the challenges being faced in the twenty-first century is the biological control of plant viral infections. Among the different strategies to combat virus infections, those based on pathogen-derived resistance (PDR) are probably the most powerful approaches to confer virus resistance in plants. The application of the PDR concept not only revealed the existence of a previously unknown sequence-specific RNA-degradation mechanism in plants, but has also helped to design antiviral strategies to engineer viral resistant plants in the last 25 years. In this article, we review the different platforms related to RNA silencing that have been developed during this time to obtain plants resistant to viruses and illustrate examples of current applications of RNA silencing to protect crop plants against viral diseases of agronomic relevance. This article is part of a Special Issue entitled: MicroRNAs in viral gene regulation.
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Hashmi JA, Zafar Y, Arshad M, Mansoor S, Asad S. Engineering cotton (Gossypium hirsutum L.) for resistance to cotton leaf curl disease using viral truncated AC1 DNA sequences. Virus Genes 2011; 42:286-96. [PMID: 21327530 DOI: 10.1007/s11262-011-0569-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2010] [Accepted: 01/03/2011] [Indexed: 11/26/2022]
Abstract
Several important biological processes are performed by distinct functional domains found on replication-associated protein (Rep) encoded by AC1 of geminiviruses. Two truncated forms of replicase (tAC1) gene, capable of expressing only the N-terminal 669 bp (5'AC1) and C-terminal 783 bp (3'AC1) nucleotides cloned under transcriptional control of the CaMV35S were introduced into cotton (Gossypium hirsutum L.) using LBA4404 strain of Agrobacterium tumefaciens to make use of an interference strategy for impairing cotton leaf curl virus (CLCuV) infection in transgenic cotton. Compared with nontransformed control, we observed that transgenic cotton plants overexpressing either N-terminal (5'AC1) or C-terminal (3'AC1) sequences confer resistance to CLCuV by inhibiting replication of viral genomic and β satellite DNA components. Molecular analysis by Northern blot hybridization revealed high transgene expression in early and late growth stages associated with inhibition of CLCuV replication. Of the eight T(1) transgenic lines tested, six had delayed and minor symptoms as compared to nontransformed control lines which developed disease symptoms after 2-3 weeks of whitefly-mediated viral delivery. Virus biological assay and growth of T(2) plants proved that transgenic cotton plants overexpressing 5'- and 3'AC1 displayed high resistance level up to 72, 81%, respectively, as compared to non-transformed control plants following inoculation with viruliferous whiteflies giving significantly high cotton seed yield. Progeny analysis of these plants by polymerase chain reaction (PCR), Southern blotting and virus biological assay showed stable transgene, integration, inheritance and cotton leaf curl disease (CLCuD) resistance in two of the eight transgenic lines having single or two transgene insertions. Transgenic cotton expressing partial AC1 gene of CLCuV can be used as virus resistance source in cotton breeding programs aiming to improve virus resistance in cotton crop.
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Affiliation(s)
- Jamil A Hashmi
- Agricultural Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), P. O. Box 577, Jhang Road, Faisalabad, Pakistan
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25
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García-Neria MA, Rivera-Bustamante RF. Characterization of Geminivirus resistance in an accession of Capsicum chinense Jacq. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2011; 24:172-182. [PMID: 20923365 DOI: 10.1094/mpmi-06-10-0126] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Pepper golden mosaic virus (PepGMV) and Pepper huasteco yellow vein virus (PHYVV), members of the Geminiviridae family, are important pathogens of pepper (Capsicum annuum L.) and other solanaceous crops. Accession BG-3821 of C. chinense Jacq. was reported earlier as resistant to mixed infection with PepGMV and PHYVV. In this work, we characterized the Geminivirus resistance trait present in BG-3821. Segregation analysis suggested that resistance depends on two genes. Our data showed that PepGMV replication in protoplast of resistant plants is approximately 70% lower when compared with the levels observed in protoplasts from susceptible plants. Additionally, viral movement is less efficient in resistant plants. We also evaluated several characteristics commonly associated with systemic acquired resistance (SAR), which is a conserved defensive mechanism. The concentration of salicylic acid was higher in resistant plants inoculated with PepGMV than in susceptible plants. Marker genes for SAR were induced after inoculation with PepGMV in resistant leaves. Similarly, we found a higher accumulation of reactive oxygen species on resistant leaves compared with susceptible ones. A model for the mechanism acting in the Geminivirus resistance detected in BG-3821 is proposed. Finally, the importance of BG-3821 in Geminivirus resistance breeding programs is discussed.
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Affiliation(s)
- Marco A García-Neria
- Departamento de Ingeniería Genética, Cinvestav Unidad Irapuato, Km 9.6 Libramiento Norte, Carretera Irapuato-León, 36821, Irapuato, Gto, Mexico
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26
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Sardo L, Lucioli A, Tavazza M, Masenga V, Tavazza R, Accotto GP, Noris E. An RGG sequence in the replication-associated protein (Rep) of Tomato yellow leaf curl Sardinia virus is involved in transcriptional repression and severely impacts resistance in Rep-expressing plants. J Gen Virol 2011; 92:204-9. [PMID: 20943892 DOI: 10.1099/vir.0.025817-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023] Open
Abstract
Truncated versions of the replication-associated protein (Rep) of Tomato yellow leaf curl Sardinia virus (TYLCSV) can interfere with various viral functions and the N-terminal 130 aa are sufficient for strongly inhibiting C1-gene transcription and virus replication and confer resistance in transgenic plants. In this work, we analysed the relevance of an RGG sequence at aa 124-126, highly conserved in begomoviruses, in these inhibitory functions as well as in the subcellular localization of Rep. Although no role of this RGG sequence was detected by cell fractionation and immunogold labelling in Rep localization, this sequence appears relevant for the transcriptional control of the C1-gene and for the inhibition of viral replication and dramatically impacts resistance in transgenic plants. These results are discussed in the context of the model of Rep-mediated resistance against TYLCSV.
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Affiliation(s)
- Luca Sardo
- Istituto di Virologia Vegetale, CNR, Strada delle Cacce 73, 10135 Torino, Italy
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Haq QMI, Ali A, Malathi VG. Engineering Resistance Against Mungbean yellow mosaic India virus Using Antisense RNA. INDIAN JOURNAL OF VIROLOGY : AN OFFICIAL ORGAN OF INDIAN VIROLOGICAL SOCIETY 2010; 21:82-5. [PMID: 23637483 DOI: 10.1007/s13337-010-0003-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2010] [Accepted: 05/29/2010] [Indexed: 11/28/2022]
Abstract
Yellow mosaic disease of cultivated legumes in South-East Asia, is caused by Mungbean yellow mosaic India virus (MYMIV) and Mungbean yellow mosaic virus (MYMV) belonging to the genus Begomovirus of the family Geminiviridae. Efforts to engineer resistance against the genus Begomovirus are focused mainly on silencing of complementary-sense virus genes involved in virus replication. Here we have targeted a complementary-sense gene (ACI) encoding Replication initiation Protein (Rep) to develop resistance against soybean isolate of Mungbean yellow mosaic India virus-[India:New Delhi:Soybean 2:1999], a bipartite begomovirus prevalent throughout the Indian subcontinent. We show that the legume host plants co-agroinoculated with infectious constructs of soybean isolate of Mungbean yellow mosaic India virus [India:New Delhi:Soybean 2:1999] along with this antisense Rep gene construct show resistance to the virus.
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Affiliation(s)
- Q M I Haq
- Advanced Centre for Plant Virology, Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi, 110012 India
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Sahu PP, Rai NK, Chakraborty S, Singh M, Chandrappa PH, Ramesh B, Chattopadhyay D, Prasad M. Tomato cultivar tolerant to Tomato leaf curl New Delhi virus infection induces virus-specific short interfering RNA accumulation and defence-associated host gene expression. MOLECULAR PLANT PATHOLOGY 2010; 11:531-44. [PMID: 20618710 PMCID: PMC6640424 DOI: 10.1111/j.1364-3703.2010.00630.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Tomato leaf curl New Delhi virus (ToLCNDV) infection causes significant yield loss in tomato. The availability of a conventional tolerance source against this virus is limited in tomato. To understand the molecular mechanism of virus tolerance in tomato, the abundance of viral genomic replicative intermediate molecules and virus-directed short interfering RNAs (siRNAs) by the host plant in a naturally tolerant cultivar H-88-78-1 and a susceptible cultivar Punjab Chhuhara at different time points after agroinfection was studied. We report that less abundance of viral replicative intermediate in the tolerant cultivar may have a correlation with a relatively higher accumulation of virus-specific siRNAs. To study defence-related host gene expression in response to ToLCNDV infection, the suppression subtractive hybridization technique was used. A library was prepared from tolerant cultivar H-88-78-1 between ToLCNDV-inoculated and Agrobacterium mock-inoculated plants of this cultivar at 21 days post-inoculation (dpi). A total of 106 nonredundant transcripts was identified and classified into 12 different categories according to their putative functions. By reverse Northern analysis and quantitative real-time polymerase chain reaction (qRT-PCR), we identified the differential expression pattern of 106 transcripts, 34 of which were up-regulated (>2.5-fold induction). Of these, eight transcripts showed more than four fold induction. qRT-PCR analysis was carried out to obtain comparative expression profiling of these eight transcripts between Punjab Chhuhara and H-88-78-1 on ToLCNDV infection. The expression patterns of these transcripts showed a significant increase in differential expression in the tolerant cultivar, mostly at 14 and 21 dpi, in comparison with that in the susceptible cultivar, as analysed by qRT-PCR. The probable direct and indirect relationship of siRNA accumulation and up-regulated transcripts with the ToLCNDV tolerance mechanism is discussed.
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Affiliation(s)
- Pranav Pankaj Sahu
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi-110067, India
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Pasumarthy KK, Choudhury NR, Mukherjee SK. Tomato leaf curl Kerala virus (ToLCKeV) AC3 protein forms a higher order oligomer and enhances ATPase activity of replication initiator protein (Rep/AC1). Virol J 2010; 7:128. [PMID: 20546567 PMCID: PMC2901266 DOI: 10.1186/1743-422x-7-128] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2010] [Accepted: 06/14/2010] [Indexed: 11/30/2022] Open
Abstract
Background Geminiviruses are emerging plant viruses that infect a wide variety of vegetable crops, ornamental plants and cereal crops. They undergo recombination during co-infections by different species of geminiviruses and give rise to more virulent species. Antiviral strategies targeting a broad range of viruses necessitate a detailed understanding of the basic biology of the viruses. ToLCKeV, a virus prevalent in the tomato crop of Kerala state of India and a member of genus Begomovirus has been used as a model system in this study. Results AC3 is a geminiviral protein conserved across all the begomoviral species and is postulated to enhance viral DNA replication. In this work we have successfully expressed and purified the AC3 fusion proteins from E. coli. We demonstrated the higher order oligomerization of AC3 using sucrose gradient ultra-centrifugation and gel-filtration experiments. In addition we also established that ToLCKeV AC3 protein interacted with cognate AC1 protein and enhanced the AC1-mediated ATPase activity in vitro. Conclusions Highly hydrophobic viral protein AC3 can be purified as a fusion protein with either MBP or GST. The purification method of AC3 protein improves scope for the biochemical characterization of the viral protein. The enhancement of AC1-mediated ATPase activity might lead to increased viral DNA replication.
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Affiliation(s)
- Kalyan K Pasumarthy
- International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi -110067, India.
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Genetically engineered virus-resistant plants in developing countries: current status and future prospects. Adv Virus Res 2010; 75:185-220. [PMID: 20109667 DOI: 10.1016/s0065-3527(09)07506-x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Plant viruses cause severe crop losses worldwide. Conventional control strategies, such as cultural methods and biocide applications against arthropod, nematode, and plasmodiophorid vectors, have limited success at mitigating the impact of plant viruses. Planting resistant cultivars is the most effective and economical way to control plant virus diseases. Natural sources of resistance have been exploited extensively to develop virus-resistant plants by conventional breeding. Non-conventional methods have also been used successfully to confer virus resistance by transferring primarily virus-derived genes, including viral coat protein, replicase, movement protein, defective interfering RNA, non-coding RNA sequences, and protease, into susceptible plants. Non-viral genes (R genes, microRNAs, ribosome-inactivating proteins, protease inhibitors, dsRNAse, RNA modifying enzymes, and scFvs) have also been used successfully to engineer resistance to viruses in plants. Very few genetically engineered (GE) virus resistant (VR) crops have been released for cultivation and none is available yet in developing countries. However, a number of economically important GEVR crops, transformed with viral genes are of great interest in developing countries. The major issues confronting the production and deregulation of GEVR crops in developing countries are primarily socio-economic and related to intellectual property rights, biosafety regulatory frameworks, expenditure to generate GE crops and opposition by non-governmental activists. Suggestions for satisfactory resolution of these factors, presumably leading to field tests and deregulation of GEVR crops in developing countries, are given.
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Yadav RK, Shukla RK, Chattopadhyay D. Soybean cultivar resistant to Mungbean Yellow Mosaic India Virus infection induces viral RNA degradation earlier than the susceptible cultivar. Virus Res 2009; 144:89-95. [PMID: 19394372 DOI: 10.1016/j.virusres.2009.04.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2008] [Revised: 03/19/2009] [Accepted: 04/05/2009] [Indexed: 11/20/2022]
Abstract
Yellow mosaic disease caused by whitefly-transmitted bipartite Geminiviruses is one of the major constraints on productivity of a number of pulse crops. We have cloned the bipartite genome of Mungbean Yellow Mosaic India Virus isolated from infected Soybean. We report here that agroinfection of Soybean seedlings with a single uncut recombinant binary plasmid containing tandem dimers of both DNA A and DNA B resulted in 100% infectivity in susceptible varieties. To understand the mechanism of natural resistance in a Soybean variety, we compared the abundance of the viral RNAs in a resistant and a susceptible variety at the early time points after agroinfection. Whilst the resistant variety displayed synthesis but rapid degradation of the early viral RNAs; the degradation in the susceptible variety was delayed resulting in accumulation of those transcripts later in infection. Accumulation of the late viral transcripts and DNA replication were detectable only in the susceptible variety. This indicates that rapid degradation of the early viral transcripts, possibly through siRNA mechanism, is one of the probable mechanisms of natural resistance against geminivirus.
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Affiliation(s)
- Rajiv Kumar Yadav
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, JNU Campus, New Delhi 110067, India
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Edelbaum D, Gorovits R, Sasaki S, Ikegami M, Czosnek H. Expressing a whitefly GroEL protein in Nicotiana benthamiana plants confers tolerance to tomato yellow leaf curl virus and cucumber mosaic virus, but not to grapevine virus A or tobacco mosaic virus. Arch Virol 2009; 154:399-407. [PMID: 19184338 DOI: 10.1007/s00705-009-0317-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2008] [Accepted: 12/29/2008] [Indexed: 10/21/2022]
Abstract
Transgenesis offers many ways to obtain virus-resistant plants. However, in most cases resistance is against a single virus or viral strain. We have taken a novel approach based on the ability of a whitefly endosymbiotic GroEL to bind viruses belonging to several genera, in vivo and in vitro. We have expressed the GroEL gene in Nicotiana benthamiana plants, postulating that upon virus inoculation, GroEL will bind to virions, thereby interfering with pathogenesis. The transgenic plants were inoculated with the begomovirus tomato yellow leaf curl virus (TYLCV) and the cucumovirus cucumber mosaic virus (CMV), both of which interacted with GroEL in vitro, and with the trichovirus grapevine virus A (GVA) and the tobamovirus tobacco mosaic virus (TMV), which did not. While the transgenic plants inoculated with TYLCV and CMV presented a high level of tolerance, those inoculated with GVA and TMV were susceptible. The amounts of virus in tolerant transgenic plants was lower by three orders of magnitude than those in non-transgenic plants; in comparison, the amounts of virus in susceptible transgenic plants were similar to those in non-transgenic plants. Leaf extracts of the tolerant plants contained GroEL-virus complexes. Hence, tolerance was correlated with trapping of viruses in planta. This study demonstrated that multiple resistances to viruses belonging to several different taxonomic genera could be achieved. Moreover, it might be hypothesized that plants expressing GroEL will be tolerant to those viruses that bind to GroEL in vitro, such as members of the genera Begomovirus, Cucumovirus, Ilarvirus, Luteovirus, and Tospovirus.
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Affiliation(s)
- Dagan Edelbaum
- The Otto Warburg Minerva Center for Agricultural Biotechnology & The Robert H. Smith Institute for Plant Science and Genetics in Agriculture, Faculty of Agriculture, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
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Lucioli A, Sallustio DE, Barboni D, Berardi A, Papacchioli V, Tavazza R, Tavazza M. A cautionary note on pathogen-derived sequences. Nat Biotechnol 2008; 26:617-9. [PMID: 18536679 DOI: 10.1038/nbt0608-617] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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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.
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Affiliation(s)
- Marcel Prins
- Laboratory of Virology, Wageningen University, Binnenhaven 11, 6709 PD, Wageningen, The Netherlands.
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Interaction with host SGS3 is required for suppression of RNA silencing by tomato yellow leaf curl virus V2 protein. Proc Natl Acad Sci U S A 2007; 105:157-61. [PMID: 18165314 DOI: 10.1073/pnas.0709036105] [Citation(s) in RCA: 195] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The V2 protein of tomato yellow leaf curl geminivirus (TYLCV) functions as an RNA-silencing suppressor that counteracts the innate immune response of the host plant. The host-cell target of V2, however, remains unknown. Here we show that V2 interacts directly with SlSGS3, the tomato homolog of the Arabidopsis SGS3 protein (AtSGS3), which is known to be involved in the RNA-silencing pathway. SlSGS3 genetically complemented an AtSGS3 mutation and restored RNA silencing, indicating that SlSGS3 is indeed a functional homolog of AtSGS3. A point mutant of V2 that is unable to bind SlSGS3 also lost its ability to suppress RNA silencing, suggesting a correlation between the V2-SlSGS3 interaction in planta and the suppressor activity of V2.
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Shepherd DN, Mangwende T, Martin DP, Bezuidenhout M, Kloppers FJ, Carolissen CH, Monjane AL, Rybicki EP, Thomson JA. Maize streak virus-resistant transgenic maize: a first for Africa. PLANT BIOTECHNOLOGY JOURNAL 2007; 5:759-67. [PMID: 17924935 DOI: 10.1111/j.1467-7652.2007.00279.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
In this article, we report transgene-derived resistance in maize to the severe pathogen maize streak virus (MSV). The mutated MSV replication-associated protein gene that was used to transform maize showed stable expression to the fourth generation. Transgenic T2 and T3 plants displayed a significant delay in symptom development, a decrease in symptom severity and higher survival rates than non-transgenic plants after MSV challenge, as did a transgenic hybrid made by crossing T2 Hi-II with the widely grown, commercial, highly MSV-susceptible, white maize genotype WM3. To the best of our knowledge, this is the first maize to be developed with transgenic MSV resistance and the first all-African-produced genetically modified crop plant.
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Affiliation(s)
- Dionne N Shepherd
- Department of Molecular and Cell Biology, University of Cape Town, Private Bag, Rondebosch 7701, South Africa.
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Bonfim K, Faria JC, Nogueira EOPL, Mendes EA, Aragão FJL. RNAi-mediated resistance to Bean golden mosaic virus in genetically engineered common bean (Phaseolus vulgaris). MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2007; 20:717-26. [PMID: 17555279 DOI: 10.1094/mpmi-20-6-0717] [Citation(s) in RCA: 148] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Bean golden mosaic virus (BGMV) is transmitted by the whitefly Bemisia tabaci in a persistent, circulative manner, causing the golden mosaic of common bean (Phaseolus vulgaris L.). The characteristic symptoms are yellow-green mosaic of leaves, stunted growth, or distorted pods. The disease is the largest constraint to bean production in Latin America and causes severe yield losses (40 to 100%). Here, we explored the concept of using an RNA interference construct to silence the sequence region of the AC1 viral gene and generate highly resistant transgenic common bean plants. Eighteen transgenic common bean lines were obtained with an intron-hairpin construction to induce post-transcriptional gene silencing against the AC1 gene. One line (named 5.1) presented high resistance (approximately 93% of the plants were free of symptoms) upon inoculation at high pressure (more than 300 viruliferous whiteflies per plant during the whole plant life cycle) and at a very early stage of plant development. Transgene-specific small interfering RNAs were detected in both inoculated and non-inoculated transgenic plants. A semiquantitative polymerase chain reaction analysis revealed the presence of viral DNA in transgenic plants exposed to viruliferous whiteflies for a period of 6 days. However, when insects were removed, no virus DNA could be detected after an additional period of 6 days.
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Affiliation(s)
- Kenny Bonfim
- Embrapa Recursos Genéticos e Biotecnologia, PqEB W5 Norte, 70770-900, Brasília, DF, Brazil
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Chilakamarthi U, Mukherjee SK, Deb JK. Intervention of geminiviral replication in yeast by ribozyme mediated downregulation of its Rep protein. FEBS Lett 2007; 581:2675-83. [PMID: 17531225 DOI: 10.1016/j.febslet.2007.04.084] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2006] [Revised: 04/20/2007] [Accepted: 04/25/2007] [Indexed: 11/29/2022]
Abstract
Geminiviruses pose serious threat to many economically important crops such as mungbean, tomato, cotton, etc. To devise a specific antiviral strategy at the viral DNA replication level, a hammerhead ribozyme was directed against the mRNA of the replication initiator protein (Rep). Rep is the most important viral protein for the DNA replication of the Mungbean yellow mosaic India virus (MYMIV), a member of the Geminiviridae family. The ribozyme showed approximately 33% cleavage activity on synthetic rep transcript within 1h under in vitro conditions, whereas the mutant ribozyme, designed to lack the catalytic activity but target the same site, showed no cleavage. The in vivo efficiency of ribozyme was evaluated in Saccharomyces cerevisiae as it can act as a surrogate host for replication of the MYMIV-DNA and lacks RNAi machinery. In the presence of the ribozyme, growth of the yeast cells that are dependent on geminiviral replication was inhibited by 30% and cellular generation time was increased by 2h. The RT-PCR analysis showed a maximum of about 50% reduction in the rep mRNA level in presence of the ribozyme compared to its noncatalytic mutant control. About 65% decrease in geminiviral DNA replication was observed due to the downregulation of replication initiator protein by the ribozyme. These results raise the possibility of engineering resistance to geminiviruses employing the ribozyme approach.
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Affiliation(s)
- Ushasri Chilakamarthi
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi, India
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Vanderschuren H, Stupak M, Fütterer J, Gruissem W, Zhang P. Engineering resistance to geminiviruses--review and perspectives. PLANT BIOTECHNOLOGY JOURNAL 2007; 5:207-20. [PMID: 17309676 DOI: 10.1111/j.1467-7652.2006.00217.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Following the conceptual development of virus resistance strategies ranging from coat protein-mediated interference of virus propagation to RNA-mediated virus gene silencing, much progress has been achieved to protect plants against RNA and DNA virus infections. Geminiviruses are a major threat to world agriculture, and breeding resistant crops against these DNA viruses is one of the major challenges faced by plant virologists and biotechnologists. In this article, we review the most recent transgene-based approaches that have been developed to achieve durable geminivirus resistance. Although most of the strategies have been tested in model plant systems, they are ready to be adopted for the protection of crop plants. Furthermore, a better understanding of geminivirus gene and protein functions, as well as the native immune system which protects plants against viruses, will allow us to develop novel tools to expand our current capacity to stabilize crop production in geminivirus epidemic zones.
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Affiliation(s)
- Hervé Vanderschuren
- Institute of Plant Sciences, ETH Zurich, Universitätstrasse 2, 8092 Zurich, Switzerland
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Ribeiro SG, Lohuis H, Goldbach R, Prins M. Tomato chlorotic mottle virus is a target of RNA silencing but the presence of specific short interfering RNAs does not guarantee resistance in transgenic plants. J Virol 2007; 81:1563-73. [PMID: 17135316 PMCID: PMC1797551 DOI: 10.1128/jvi.01238-06] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2006] [Accepted: 11/16/2006] [Indexed: 11/20/2022] Open
Abstract
Tomato chlorotic mottle virus (ToCMoV) is a begomovirus found widespread in tomato fields in Brazil. ToCMoV isolate BA-Se1 (ToCMoV-[BA-Se1]) was shown to trigger the plant RNA silencing surveillance in different host plants and, coinciding with a decrease in viral DNA levels, small interfering RNAs (siRNAs) specific to ToCMoV-[BA-Se1] accumulated in infected plants. Although not homogeneously distributed, the siRNA population in both infected Nicotiana benthamiana and tomato plants represented the entire DNA-A and DNA-B genomes. We determined that in N. benthamiana, the primary targets corresponded to the 5' end of AC1 and the embedded AC4, the intergenic region and 5' end of AV1 and overlapping central part of AC5. Subsequently, transgenic N. benthamiana plants were generated that were preprogrammed to express double-stranded RNA corresponding to this most targeted portion of the virus genome by using an intron-hairpin construct. These plants were shown to indeed produce ToCMoV-specific siRNAs. When challenge inoculated, most transgenic lines showed significant delays in symptom development, and two lines had immune plants. Interestingly, the levels of transgene-produced siRNAs were similar in resistant and susceptible siblings of the same line. This indicates that, in contrast to RNA viruses, the mere presence of transgene siRNAs corresponding to DNA virus sequences does not guarantee virus resistance and that other factors may play a role in determining RNA-mediated resistance to DNA viruses.
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Affiliation(s)
- Simone G Ribeiro
- Laboratory of Virology, Binnenhaven 11, 6709 PD Wageningen, The Netherlands
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Pal A, Chakrabarti A, Basak J. New motifs within the NB-ARC domain of R proteins: probable mechanisms of integration of geminiviral signatures within the host species of Fabaceae family and implications in conferring disease resistance. J Theor Biol 2007; 246:564-73. [PMID: 17320114 DOI: 10.1016/j.jtbi.2007.01.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2006] [Revised: 12/30/2006] [Accepted: 01/13/2007] [Indexed: 10/23/2022]
Abstract
The Gemini viruses are a group of plant infectious agents, of which mungbean yellow mosaic India virus (MYMIV) belongs to the bipartite subgroup of Gemini virus and causes serious yield penalty in the leguminous group of plants. In this investigation we have isolated two resistant gene homologues (RGHs; AY301990, AY301991) from two MYMIV-resistant lines of Vigna mungo and V. radiata that have high homology with a MYMIV-resistant linked marker, VMYR1 (AY 297425). These three resistance factors also have similarity with 221 reported R gene/RGH sequences in the NB-ARC domain of the family Fabaceae. NB-ARC domain is an ancient, highly conserved domain of a class of plant disease resistance genes/proteins. Out of 221 in silico translated protein sequences, multialignment of 188 sequences without large insertion or truncation, unlike that of the rest 33, illustrated presence of both TIR and non-TIR subfamilies of NB-ARC domain. A critical analysis of these sequences revealed eight new conserved motifs, in addition to the reported conserved motifs within the NB-ARC domains, which are hitherto not reported. Further analysis of these eight motifs with the aid of PRINTS and PROSITE databases revealed signatures of geminiviral coat protein (GVCP) within the favoured allele, R gene or RGHs. GVCP signatures are absent within the NB-ARC domain of three species of Medicago, which are non-host to Gemini virus. These observations tempted us to predict probable mechanism of integration of GVCP within the plant R gene/RGHs and their implications in conferring geminiviral disease resistance to the host plants. Our conjecture is that these signatures were integrated during plant pathogen interaction and are being maintained within this conserved domain through active selection of the favoured allele. We comprehensively addressed the biological significance of GVCP signatures, which probably provides additional defense against Gemini viruses through degradation of homologous transcript of the virus.
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Affiliation(s)
- Amita Pal
- Plant Molecular and Cellular Genetics, Bose Institute, P 1/12 CIT Scheme VIIM, Kolkata 700054, India.
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Carrillo-Tripp J, Lozoya-Gloria E, Rivera-Bustamante RF. Symptom Remission and Specific Resistance of Pepper Plants After Infection by Pepper golden mosaic virus. PHYTOPATHOLOGY 2007; 97:51-9. [PMID: 18942936 DOI: 10.1094/phyto-97-0051] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
ABSTRACT Pepper golden mosaic virus (PepGMV) is an important begomovirus infecting solanaceous crops in Mexico and Central America. Under controlled conditions for growth and inoculation with a low-pressure biolistic device, PepGMV-infected pepper plants consistently showed symptom remission or host recovery 12 to 15 days postinoculation (dpi). Inoculated plants initially developed the characteristic PepGMV symptoms; however, newer leaves presented a significant decrease or disappearance of symptoms. Younger asymptomatic, recovered leaves accumulated lower quantities of viral DNA and transcripts than the ones found in the symptomatic tissue. Nonetheless, viral DNA did not disappear during the evaluation period (up to 35 dpi), suggesting that a population of viral molecules escape from plant defensive mechanisms to maintain a subliminal, symptomless infection. Recovery was correlated with a specific resistance to PepGMV but not to Pepper huasteco yellow vein virus, a different gemi-nivirus commonly found in mixed infections with PepGMV. Virus-related small interfering RNAs were detected in practically all tissues (from symptomatic to recovered leaves) but it was not possible to establish a correlation between concentration and symptom severity. The participation of a posttranscriptional gene silencing mechanism in the recovery process and specific resistance is discussed.
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Shivaprasad PV, Thillaichidambaram P, Balaji V, Veluthambi K. Expression of full-length and truncated Rep genes from Mungbean yellow mosaic virus-Vigna inhibits viral replication in transgenic tobacco. Virus Genes 2006; 33:365-74. [PMID: 16991009 DOI: 10.1007/s11262-006-0077-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2005] [Accepted: 06/05/2006] [Indexed: 10/24/2022]
Abstract
Mungbean yellow mosaic virus-Vigna (MYMV-Vig) is a bipartite geminivirus that causes a severe yellow mosaic disease in blackgram. An assay was developed to study MYMV-Vig replication by agroinoculation of tobacco leaf discs with partial dimers of the virus. This assay, in a non-host model plant, was used to evaluate pathogen-derived resistance contributed by MYMV-Vig genes in transgenic plants. Viral DNA accumulation was optimum in tobacco leaf discs cultured for 10 days after infection with Agrobacterium tumefaciens strain Ach5 containing partial dimers of both DNA A and DNA B of MYMV-Vig. Transgenic tobacco plants with MYMV-Vig genes for coat protein (CP), replication-associated protein (Rep)-sense, Rep-antisense, truncated Rep (T-Rep), nuclear shuttle protein (NSP) and movement protein (MP) were generated. Leaf discs from transgenic tobacco plants, harbouring MYMV-Vig genes, were agroinoculated with partial dimers of MYMV-Vig and analyzed for viral DNA accumulation. The leaf discs from transgenic tobacco plants harbouring CP and MP genes supported the accumulation of higher levels of MYMV-Vig DNA. However, MYMV-Vig accumulation was inhibited in one transgenic plant harbouring the Rep-sense gene and in two plants harbouring the T-Rep gene. Northern analysis of these plants revealed a good correlation between expression of Rep or T-Rep genes and inhibition of MYMV-Vig accumulation.
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Affiliation(s)
- Padubidri V Shivaprasad
- Department of Plant Biotechnology, School of Biotechnology, Madurai Kamaraj University, Madurai, Tamilnadu, 625 021, India
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44
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Legg JP, Owor B, Sseruwagi P, Ndunguru J. Cassava mosaic virus disease in East and Central Africa: epidemiology and management of a regional pandemic. Adv Virus Res 2006; 67:355-418. [PMID: 17027685 DOI: 10.1016/s0065-3527(06)67010-3] [Citation(s) in RCA: 121] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- J P Legg
- International Institute of Tropical Agriculture, Dar es Salaam, Tanzania
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45
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Lopez-Ochoa L, Ramirez-Prado J, Hanley-Bowdoin L. Peptide aptamers that bind to a geminivirus replication protein interfere with viral replication in plant cells. J Virol 2006; 80:5841-53. [PMID: 16731923 PMCID: PMC1472579 DOI: 10.1128/jvi.02698-05] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The AL1 protein of tomato golden mosaic virus (TGMV), a member of the geminivirus family, is essential for viral replication in plants. Its N terminus contains three conserved motifs that mediate origin recognition and DNA cleavage during the initiation of rolling-circle replication. We used the N-terminal domain of TGMV AL1 as bait in a yeast two-hybrid screen of a random peptide aptamer library constrained in the active site of the thioredoxin A (TrxA) gene. The screen selected 88 TrxA peptides that also bind to the full-length TGMV AL1 protein. Plant expression cassettes corresponding to the TrxA peptides and a TGMV A replicon encoding AL1 were cotransfected into tobacco protoplasts, and viral DNA replication was monitored by semiquantitative PCR. In these assays, 31 TrxA peptides negatively impacted TGMV DNA accumulation, reducing viral DNA levels to 13 to 64% of those of the wild type. All of the interfering aptamers also bound to the AL1 protein of cabbage leaf curl virus. A comparison of the 20-mer peptides revealed that their sequences are not random. The alignments detected seven potential binding motifs, five of which are more highly represented among the interfering peptides. One motif was present in 18 peptides, suggesting that these peptides interact with a hot spot in the AL1 N terminus. The peptide aptamers characterized in these studies represent new tools for studying AL1 function and can serve as the basis for the development of crops with broad-based resistance to single-stranded DNA viruses.
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Affiliation(s)
- Luisa Lopez-Ochoa
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC 27695-7622, USA
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46
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Abhary MK, Anfoka GH, Nakhla MK, Maxwell DP. Post-transcriptional gene silencing in controlling viruses of the Tomato yellow leaf curl virus complex. Arch Virol 2006; 151:2349-63. [PMID: 16862387 DOI: 10.1007/s00705-006-0819-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2005] [Accepted: 06/09/2006] [Indexed: 10/24/2022]
Abstract
Tomato yellow leaf curl disease (TYLCD) is caused by a group of geminiviruses that belong to the Tomato yellow leaf curl virus (TYLCV) complex and are transmitted by the whitefly (Bemisia tabaci Genn.). The disease causes great yield losses in many countries throughout the Mediterranean region and the Middle East. In this study, the efficacy of post-transcriptional gene silencing (PTGS) to control the disease caused by TYLCV complex was investigated. Non-coding conserved regions from the genome of TYLCV, Tomato yellow leaf curl virus-mild, tomato yellow leaf curl Sardinia virus, tomato yellow leaf curl Malaga virus, and tomato yellow leaf curl Sardinia virus-Spain [2] were selected and used to design a construct that can trigger broad resistance against different viruses that cause tomato yellow leaf curl disease. The silencing construct was cloned into an Agrobacterium-binary vector in sense and antisense orientation and used in transient assay to infiltrate tomato and Nicotiana benthamiana plants. A high level of resistance was obtained when plants were agro-infiltrated with an infectious clone of the Egyptian isolate of TYLCV (TYLCV-[EG]) or challenge inoculated with TYLCV, TYLCV-Mld, and TYLCSV-ES[2] using whitefly-mediated transmission 16-20 days post infiltration with the silencing construct. Results of the polymerase chain reaction showed that the resistance was effective against all three viruses. Furthermore, dot blot hybridization and PCR failed to detect viral DNA in symptomless, silenced plants. A positive correlation between resistance and the accumulation of TYLCV-specific siRNAs was observed in silenced plants. Together, these data provide compelling evidence that PTGS can be used to engineer geminivirus-resistant plants.
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Affiliation(s)
- M K Abhary
- Department of Biotechnology, Faculty of Agricultural Technology, Al-Balqa' Applied University, Al-Salt, Jordan
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47
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Bian XY, Rasheed MS, Seemanpillai MJ, Ali Rezaian M. Analysis of silencing escape of tomato leaf curl virus: an evaluation of the role of DNA methylation. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2006; 19:614-24. [PMID: 16776295 DOI: 10.1094/mpmi-19-0614] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
RNA silencing is a sequence-specific mechanism regulating gene expression and has been used successfully for antiviral defense against RNA viruses. Similar strategies to develop resistance against DNA containing Tomato leaf curl virus (TLCV) and some other geminiviruses have been unsuccessful. To analyze this silencing escape, we transformed tomato plants with a hairpin construct from the TLCV C2 open reading frame (ORF). The transgenic plants showed a strong RNA silencing response, and following TLCV inoculation, their infection was delayed. However, the viral infection was not prevented and TLCV DNA accumulated to the levels found in nontransgenic plants. To determine the fate of a transgene carrying homology to the virus, we used transgenic plants carrying the TLCV C4 gene, which induces a distinct phenotype. Upon TLCV infection, the phenotype was abolished and C4 transcript disappeared. Concurrently, TLCV-specific small interfering RNAs were produced. In situ hybridization showed abundant levels of TLCV DNA in phloem cells of TLCV-infected C4 transgenic plants. However, the C4 transcripts were no longer detectable in nonvascular cells. Analysis of the transgene by methylation sequencing revealed a high level of de novo methylation of asymmetric cytosines in both the C4 ORF and its 35S promoter. A high level of methylation also was found at both symmetric and asymmetric cytosines of the complementary-sense strand of TLCV double-stranded DNA. Given the previous finding that methylated geminiviral DNA is not competent for replication, we provide a model whereby TLCV evades host defense through a population of de novo synthesized unmethylated DNA.
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Affiliation(s)
- Xue-Yu Bian
- CSIRO Plant Industry, PO Box 350, Glen Osmond, SA 5064, Australia
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48
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Abstract
RNA silencing is an RNA-directed gene regulatory system that is present in a wide range of eukaryotes, and which functions as an antiviral defense in plants. Silencing pathways are complex and partially overlapping, but at least three basic classes can be distinguished: cytoplasmic RNA silencing (or post-transcriptional gene silencing; PTGS) mediated by small interfering RNAs (siRNAs), silencing mediated by microRNAs (miRNAs), and transcriptional gene silencing (TGS) mediated by siRNA-directed methylation of DNA and histone proteins. Recent advances in our understanding of different geminivirus silencing suppressors indicate that they can affect all three pathways, suggesting that multiple aspects of silencing impact geminivirus replication.
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Affiliation(s)
- David M Bisaro
- Department of Molecular Genetics and Plant Biotechnology Center, The Ohio State University, Columbus, OH 43210, USA.
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49
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Akbergenov R, Si-Ammour A, Blevins T, Amin I, Kutter C, Vanderschuren H, Zhang P, Gruissem W, Meins F, Hohn T, Pooggin MM. Molecular characterization of geminivirus-derived small RNAs in different plant species. Nucleic Acids Res 2006; 34:462-71. [PMID: 16421273 PMCID: PMC1342034 DOI: 10.1093/nar/gkj447] [Citation(s) in RCA: 191] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2005] [Revised: 12/23/2005] [Accepted: 01/03/2006] [Indexed: 11/23/2022] Open
Abstract
DNA geminiviruses are thought to be targets of RNA silencing. Here, we characterize small interfering (si) RNAs-the hallmarks of silencing-associated with Cabbage leaf curl begomovirus in Arabidopsis and African cassava mosaic begomovirus in Nicotiana benthamiana and cassava. We detected 21, 22 and 24 nt siRNAs of both polarities, derived from both the coding and the intergenic regions of these geminiviruses. Genetic evidence showed that all the 24 nt and a substantial fraction of the 22 nt viral siRNAs are generated by the dicer-like proteins DCL3 and DCL2, respectively. The viral siRNAs were 5' end phosphorylated, as shown by phosphatase treatments, and methylated at the 3'-nucleotide, as shown by HEN1 miRNA methylase-dependent resistance to beta-elimination. Similar modifications were found in all types of endogenous and transgene-derived siRNAs tested, but not in a major fraction of siRNAs from a cytoplasmic RNA tobamovirus. We conclude that several distinct silencing pathways are involved in DNA virus-plant interactions.
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Affiliation(s)
- Rashid Akbergenov
- Institute of Botany, University of BaselSchönbeinstrasse 6, 4056 Basel, Switzerland
| | - Azeddine Si-Ammour
- Friedrich Miescher Institute for Biomedical ResearchMaulbeerstrasse 66, 4058 Basel, Switzerland
| | - Todd Blevins
- Friedrich Miescher Institute for Biomedical ResearchMaulbeerstrasse 66, 4058 Basel, Switzerland
| | - Imran Amin
- Institute of Botany, University of BaselSchönbeinstrasse 6, 4056 Basel, Switzerland
| | - Claudia Kutter
- Friedrich Miescher Institute for Biomedical ResearchMaulbeerstrasse 66, 4058 Basel, Switzerland
| | - Herve Vanderschuren
- Institute of Plant Sciences, ETH-Zurich, LFW E17, Universitätstrasse 28092 Zürich, Switzerland
| | - Peng Zhang
- Institute of Plant Sciences, ETH-Zurich, LFW E17, Universitätstrasse 28092 Zürich, Switzerland
| | - Wilhelm Gruissem
- Institute of Plant Sciences, ETH-Zurich, LFW E17, Universitätstrasse 28092 Zürich, Switzerland
| | - Frederick Meins
- Friedrich Miescher Institute for Biomedical ResearchMaulbeerstrasse 66, 4058 Basel, Switzerland
| | - Thomas Hohn
- Institute of Botany, University of BaselSchönbeinstrasse 6, 4056 Basel, Switzerland
- Friedrich Miescher Institute for Biomedical ResearchMaulbeerstrasse 66, 4058 Basel, Switzerland
| | - Mikhail M. Pooggin
- Institute of Botany, University of BaselSchönbeinstrasse 6, 4056 Basel, Switzerland
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50
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Di Nicola-Negri E, Brunetti A, Tavazza M, Ilardi V. Hairpin RNA-mediated silencing of Plum pox virus P1 and HC-Pro genes for efficient and predictable resistance to the virus. Transgenic Res 2005; 14:989-94. [PMID: 16315100 DOI: 10.1007/s11248-005-1773-y] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2005] [Accepted: 08/05/2005] [Indexed: 10/25/2022]
Abstract
We report the application of the hairpin-mediated RNA silencing technology for obtaining resistance to Plum pox virus (PPV) infection in Nicotiana benthamiana plants. Four sequences, covering the P1 and silencing suppressor HC-Pro genes of an Italian PPV M isolate, were introduced into N. benthamiana plants as two inverted repeats separated by an intron sequence under the transcriptional control of the Cauliflower Mosaic Virus 35S promoter. In a leaf disk infection assay, 38 out of 40 T0 transgenic plants were resistant to PPV infection. Eight lines, 2 for each construct, randomly selected among the 38 resistant plants were further analysed. Two hundred forty eight out of 253 T1 transgenic plants were resistant to local and systemic PPV infection. All transgenic single locus lines were completely resistant. These data indicate that the RNA silencing of PPV P1/HCPro sequences results in an efficient and predictable PPV resistance, which may be utilized in obtaining stone fruit plants resistant to the devastating Sharka disease.
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Affiliation(s)
- Elisa Di Nicola-Negri
- Section of General Pathology and Physiopathology, CRA Plant Pathology Research Institute, Rome, Italy
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