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Alburquerque N, Pérez-Caselles C, Faize L, Ilardi V, Burgos L. Trans-grafting plum pox virus resistance from transgenic plum rootstocks to apricot scions. FRONTIERS IN PLANT SCIENCE 2023; 14:1216217. [PMID: 37828929 PMCID: PMC10565502 DOI: 10.3389/fpls.2023.1216217] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 09/06/2023] [Indexed: 10/14/2023]
Abstract
Introduction Trans-grafting could be a strategy to transfer virus resistance from a transgenic rootstock to a wild type scion. However contradictory results have been obtained in herbaceous and woody plants. This work was intended to determine if the resistance to sharka could be transferred from transgenic plum rootstocks to wild-type apricot scions grafted onto them. Methods To this end, we conducted grafting experiments of wild- type apricots onto plum plants transformed with a construction codifying a hairpin RNA designed to silence the PPV virus and studied if the resistance was transmitted from the rootstock to the scion. Results Our data support that the RNA-silencing-based PPV resistance can be transmitted from PPV-resistant plum rootstocks to non-transgenic apricot scions and that its efficiency is augmented after successive growth cycles. PPV resistance conferred by the rootstocks was robust, already occurring within the same growing cycle and maintained in successive evaluation cycles. The RNA silencing mechanism reduces the relative accumulation of the virus progressively eliminating the virus from the wild type scions grafted on the transgenic resistant PPV plants. There was a preferential accumulation of the 24nt siRNAs in the scions grafted onto resistant rootstocks that was not found in the scions grafted on the susceptible rootstock. This matched with a significantly lower relative accumulation of hpRNA in the resistant rootstocks compared with the susceptible or the tolerant ones. Discussion Using transgenic rootstocks should mitigate public concerns about transgenes dispersion and eating transgenic food and allow conferring virus resistance to recalcitrant to transformation cultivars or species.
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Affiliation(s)
- Nuria Alburquerque
- Fruit Biotechnology Group, Department of Plant Breeding, Centro de Edafología y Biología Aplicada del Segura- Consejo Superior de Investigaciones Científicas (CEBAS-CSIC), Murcia, Spain
| | - Cristian Pérez-Caselles
- Fruit Biotechnology Group, Department of Plant Breeding, Centro de Edafología y Biología Aplicada del Segura- Consejo Superior de Investigaciones Científicas (CEBAS-CSIC), Murcia, Spain
| | - Lydia Faize
- Fruit Biotechnology Group, Department of Plant Breeding, Centro de Edafología y Biología Aplicada del Segura- Consejo Superior de Investigaciones Científicas (CEBAS-CSIC), Murcia, Spain
| | - Vincenza Ilardi
- Research Centre for Plant Protection and Certification, Council for Agricultural Research and Economics (CREA-DC), Rome, Italy
| | - Lorenzo Burgos
- Fruit Biotechnology Group, Department of Plant Breeding, Centro de Edafología y Biología Aplicada del Segura- Consejo Superior de Investigaciones Científicas (CEBAS-CSIC), Murcia, Spain
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Wang MR, Bi WL, Ren L, Zhang AL, Ma XY, Zhang D, Volk GM, Wang QC. Micrografting: An Old Dog Plays New Tricks in Obligate Plant Pathogens. PLANT DISEASE 2022; 106:2545-2557. [PMID: 35350886 DOI: 10.1094/pdis-03-22-0475-fe] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Micrografting, which was developed almost 50 years ago, has long been used for virus eradication, micropropagation, regeneration, rejuvenation, and graft compatibility. Recently, micrografting has been used for studies of long-distance trafficking and signaling of molecules between scions and rootstocks. The graft transmissiveness of obligate plant pathogens, such as viruses, viroids, and phytoplasmas, facilitated the use of micrografting to study biological indexing and pathogen transmission, pathogen-induced graft incompatibility, and screening for the pathogen resistance during the past 20 years. The present study provides comprehensive information on the latter subjects. Finally, prospects are proposed to direct further studies.
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Affiliation(s)
- Min-Rui Wang
- College of Life Science, State Key Laboratory of Crop Stress Biology for Arid Region, Yangling 712100, Shaanxi, P.R. China
- College of Horticulture, Northwest A&F University, Yangling 712100, Shaanxi, P.R. China
| | - Wen-Lu Bi
- Department of Plant Agriculture, Gosling Research Institute for Plant Preservation, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Li Ren
- Institute for Agri-Food Standards and Testing Technology, Shanghai Academy of Agricultural Sciences, Shanghai 201403, P.R. China
| | - A-Ling Zhang
- College of Horticulture, Northwest A&F University, Yangling 712100, Shaanxi, P.R. China
| | - Xiao-Yan Ma
- College of Horticulture, Northwest A&F University, Yangling 712100, Shaanxi, P.R. China
| | - Dong Zhang
- College of Horticulture, Northwest A&F University, Yangling 712100, Shaanxi, P.R. China
| | - Gayle M Volk
- USDA-ARS National Laboratory for Genetic Resources Preservation, 1111 S. Mason Street, Fort Collins, CO 80521, U.S.A
| | - Qiao-Chun Wang
- College of Horticulture, Northwest A&F University, Yangling 712100, Shaanxi, P.R. China
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Carbonell A. RNAi tools for controlling viroid diseases. Virus Res 2022; 313:198729. [DOI: 10.1016/j.virusres.2022.198729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 03/02/2022] [Accepted: 03/05/2022] [Indexed: 12/01/2022]
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Tsaballa A, Xanthopoulou A, Madesis P, Tsaftaris A, Nianiou-Obeidat I. Vegetable Grafting From a Molecular Point of View: The Involvement of Epigenetics in Rootstock-Scion Interactions. FRONTIERS IN PLANT SCIENCE 2021; 11:621999. [PMID: 33488662 PMCID: PMC7817540 DOI: 10.3389/fpls.2020.621999] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 12/07/2020] [Indexed: 05/25/2023]
Abstract
Vegetable grafting is extensively used today in agricultural production to control soil-borne pathogens, abiotic and biotic stresses and to improve phenotypic characteristics of the scion. Commercial vegetable grafting is currently practiced in tomato, watermelon, melon, eggplant, cucumber, and pepper. It is also regarded as a rapid alternative to the relatively slow approach of breeding for increased environmental-stress tolerance of fruit vegetables. However, even though grafting has been used for centuries, until today, there are still many issues that have not been elucidated. This review will emphasize on the important mechanisms taking place during grafting, especially the genomic interactions between grafting partners and the impact of rootstocks in scion's performance. Special emphasis will be drawn on the relation between vegetable grafting, epigenetics, and the changes in morphology and quality of the products. Recent advances in plant science such as next-generation sequencing provide new information regarding the molecular interactions between rootstock and scion. It is now evidenced that genetic exchange is happening across grafting junctions between rootstock and scion, potentially affecting grafting-mediated effects already recorded in grafted plants. Furthermore, significant changes in DNA methylation are recorded in grafted scions, suggesting that these epigenetic mechanisms could be implicated in grafting effects. In this aspect, we also discuss the process and the molecular aspects of rootstock scion communication. Finally, we provide with an extensive overview of gene expression changes recorded in grafted plants and how these are related to the phenotypic changes observed. Τhis review finally seeks to elucidate the dynamics of rootstock-scion interactions and thus stimulate more research on grafting in the future. In a future where sustainable agricultural production is the way forward, grafting could play an important role to develop products of higher yield and quality in a safe and "green" way.
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Affiliation(s)
- Aphrodite Tsaballa
- Institute of Plant Breeding and Genetic Resources, Hellenic Agricultural Organization (ELGO-Dimitra), Thessaloniki, Greece
| | - Aliki Xanthopoulou
- Institute of Plant Breeding and Genetic Resources, Hellenic Agricultural Organization (ELGO-Dimitra), Thessaloniki, Greece
| | - Panagiotis Madesis
- Laboratory of Molecular Biology of Plants, School of Agricultural Sciences, University of Thessaly, Volos, Greece
- Institute of Applied Biosciences, Centre for Research & Technology Hellas, Thessaloniki, Greece
| | - Athanasios Tsaftaris
- Perrotis College, American Farm School, Thessaloniki, Greece
- Laboratory of Genetics and Plant Breeding, School of Agriculture, Forestry and Natural Environment, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Irini Nianiou-Obeidat
- Laboratory of Genetics and Plant Breeding, School of Agriculture, Forestry and Natural Environment, Aristotle University of Thessaloniki, Thessaloniki, Greece
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Sidorova T, Miroshnichenko D, Kirov I, Pushin A, Dolgov S. Effect of Grafting on Viral Resistance of Non-transgenic Plum Scion Combined With Transgenic PPV-Resistant Rootstock. FRONTIERS IN PLANT SCIENCE 2021; 12:621954. [PMID: 33597963 PMCID: PMC7882617 DOI: 10.3389/fpls.2021.621954] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 01/08/2021] [Indexed: 05/03/2023]
Abstract
In stone fruit trees, resistance to Plum pox virus (PPV) can be achieved through the specific degradation of viral RNA by the mechanism of RNA interference (RNAi). Transgenic virus-resistant plants, however, raise serious biosafety concerns due to the insertion and expression of hairpin constructs that usually contain various selective foreign genes. Since a mature stone tree represents a combination of scion and rootstock, grafting commercial varieties onto transgenic virus-tolerant rootstocks is a possible approach to mitigate biosafety problems. The present study was aimed at answering the following question: To what extent are molecular RNAi silencing signals transmitted across graft junctions in transgrafted plum trees and how much does it affect PPV resistance in genetically modified (GM)/non-transgenic (NT) counterparts? Two combinations, NT:GM and GM:NT (scion:rootstock), were studied, with an emphasis on the first transgrafting scenario. Viral inoculation was carried out on either the scion or the rootstock. The interspecific rootstock "Elita" [(Prunus pumila L. × P. salicina Lindl.) × (P. cerasifera Ehrh.)] was combined with cv. "Startovaya" (Prunus domestica L.) as a scion. Transgenic plum lines of both cultivars were transformed with a PPV-coat protein (CP)-derived intron-separate hairpin-RNA construct and displayed substantial viral resistance. High-throughput sequence data of small RNA (sRNA) pools indicated that the accumulation of construct-specific small interfering RNA (siRNA) in transgenic plum rootstock reached over 2%. The elevated siRNA level enabled the resistance to PPV and blocked the movement of the virus through the GM tissues into the NT partner when the transgenic tissues were inoculated. At the same time, the mobile siRNA signal was not moved from the GM rootstock to the target NT tissue to a level sufficient to trigger silencing of PPV transcripts and provide reliable viral resistance. The lack of mobility of transgene-derived siRNA molecules was accompanied by the transfer of various endogenous rootstock-specific sRNAs into the NT scion, indicating the exceptional transitivity failure of the studied RNAi signal. The results presented here indicate that transgrafting in woody fruit trees remains an unpredictable practice and needs further in-depth examination to deliver molecular silencing signals.
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Affiliation(s)
- Tatiana Sidorova
- Branch of Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Science, Pushchino, Russia
- *Correspondence: Tatiana Sidorova,
| | - Dmitry Miroshnichenko
- Branch of Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Science, Pushchino, Russia
- All-Russia Research Institute of Agricultural Biotechnology, Russian Academy of Science, Moscow, Russia
| | - Ilya Kirov
- All-Russia Research Institute of Agricultural Biotechnology, Russian Academy of Science, Moscow, Russia
| | - Alexander Pushin
- Branch of Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Science, Pushchino, Russia
- All-Russia Research Institute of Agricultural Biotechnology, Russian Academy of Science, Moscow, Russia
| | - Sergey Dolgov
- Branch of Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Science, Pushchino, Russia
- All-Russia Research Institute of Agricultural Biotechnology, Russian Academy of Science, Moscow, Russia
- Federal Horticulture Center for Breeding, Agrotechnology and Nursery, Moscow, Russia
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Spanò R, Ferrara M, Gallitelli D, Mascia T. The Role of Grafting in the Resistance of Tomato to Viruses. PLANTS (BASEL, SWITZERLAND) 2020; 9:E1042. [PMID: 32824316 PMCID: PMC7463508 DOI: 10.3390/plants9081042] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 08/07/2020] [Accepted: 08/12/2020] [Indexed: 12/14/2022]
Abstract
Grafting is routinely implemented in modern agriculture to manage soilborne pathogens such as fungi, oomycetes, bacteria, and viruses of solanaceous crops in a sustainable and environmentally friendly approach. Some rootstock/scion combinations use specific genetic resistance mechanisms to impact also some foliar and airborne pathogens, including arthropod or contact-transmitted viruses. These approaches resulted in poor efficiency in the management of plant viruses with superior virulence such as the strains of tomato spotted wilt virus breaking the Sw5 resistance, strains of cucumber mosaic virus carrying necrogenic satellite RNAs, and necrogenic strains of potato virus Y. Three different studies from our lab documented that suitable levels of resistance/tolerance can be obtained by grafting commercial tomato varieties onto the tomato ecotype Manduria (Ma) rescued in the framework of an Apulian (southern Italy) regional program on biodiversity. Here we review the main approaches, methods, and results of the three case studies and propose some mechanisms leading to the tolerance/resistance observed in susceptible tomato varieties grafted onto Ma as well as in self-grafted plants. The proposed mechanisms include virus movement in plants, RNA interference, genes involved in graft wound response, resilience, and tolerance to virus infection.
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Affiliation(s)
- Roberta Spanò
- Department of Soil, Plant and Food Sciences, University of Bari “Aldo Moro”, 70126 Bari, Italy; (D.G.); (T.M.)
| | - Massimo Ferrara
- Institute of Sciences of Food Production (ISPA)—CNR, 70126 Bari, Italy;
| | - Donato Gallitelli
- Department of Soil, Plant and Food Sciences, University of Bari “Aldo Moro”, 70126 Bari, Italy; (D.G.); (T.M.)
| | - Tiziana Mascia
- Department of Soil, Plant and Food Sciences, University of Bari “Aldo Moro”, 70126 Bari, Italy; (D.G.); (T.M.)
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7
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Grafting alters tomato transcriptome and enhances tolerance to an airborne virus infection. Sci Rep 2020; 10:2538. [PMID: 32054920 PMCID: PMC7018947 DOI: 10.1038/s41598-020-59421-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 01/24/2020] [Indexed: 12/22/2022] Open
Abstract
Grafting of commercial tomato varieties and hybrids on the tomato ecotype Manduria resulted in high levels of tolerance to the infection of Sw5 resistance-breaking strains of tomato spotted wilt virus and of severe cucumber mosaic virus strains supporting hypervirulent satellite RNAs that co-determine stunting and necrotic phenotypes in tomato. To decipher the basis of such tolerance, here we used a RNAseq analysis to study the transcriptome profiles of the Manduria ecotype and of the susceptible variety UC82, and of their graft combinations, exposed or not to infection of the potato virus Y recombinant strain PVYC-to. The analysis identified graft- and virus-responsive mRNAs differentially expressed in UC82 and Manduria, which led to an overall suitable level of tolerance to viral infection confirmed by the appearance of a recovery phenotype in Manduria and in all graft combinations. The transcriptome analysis suggested that graft wounding and viral infection had diverging effects on tomato transcriptome and that the Manduria ecotype was less responsive than the UC82 to both graft wounding and potyviral infection. We propose that the differential response to the two types of stress could account for the tolerance to viral infection observed in the Manduria ecotype as well as in the susceptible tomato variety UC82 self-grafted or grafted on the Manduria ecotype.
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8
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Spanò R, Ferrara M, Montemurro C, Mulè G, Gallitelli D, Mascia T. Grafting alters tomato transcriptome and enhances tolerance to an airborne virus infection. Sci Rep 2020. [PMID: 32054920 DOI: 10.1038/s41598-020-59421-59425] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2023] Open
Abstract
Grafting of commercial tomato varieties and hybrids on the tomato ecotype Manduria resulted in high levels of tolerance to the infection of Sw5 resistance-breaking strains of tomato spotted wilt virus and of severe cucumber mosaic virus strains supporting hypervirulent satellite RNAs that co-determine stunting and necrotic phenotypes in tomato. To decipher the basis of such tolerance, here we used a RNAseq analysis to study the transcriptome profiles of the Manduria ecotype and of the susceptible variety UC82, and of their graft combinations, exposed or not to infection of the potato virus Y recombinant strain PVYC-to. The analysis identified graft- and virus-responsive mRNAs differentially expressed in UC82 and Manduria, which led to an overall suitable level of tolerance to viral infection confirmed by the appearance of a recovery phenotype in Manduria and in all graft combinations. The transcriptome analysis suggested that graft wounding and viral infection had diverging effects on tomato transcriptome and that the Manduria ecotype was less responsive than the UC82 to both graft wounding and potyviral infection. We propose that the differential response to the two types of stress could account for the tolerance to viral infection observed in the Manduria ecotype as well as in the susceptible tomato variety UC82 self-grafted or grafted on the Manduria ecotype.
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Affiliation(s)
- Roberta Spanò
- Dipartimento di Scienze del Suolo della Pianta e degli Alimenti, Università degli Studi di Bari "Aldo Moro", Via Amendola 165/A, 70126, Bari, Italy.
- Istituto per la Protezione Sostenibile delle Piante (IPSP) - CNR, UOS Bari, Via Amendola 122/D, 70126, Bari, Italy.
| | - Massimo Ferrara
- Istituto di Scienze delle Produzioni Alimentari (ISPA) - CNR Via Amendola 122/O, 70126, Bari, Italy
| | - Cinzia Montemurro
- Dipartimento di Scienze del Suolo della Pianta e degli Alimenti, Università degli Studi di Bari "Aldo Moro", Via Amendola 165/A, 70126, Bari, Italy
- Istituto per la Protezione Sostenibile delle Piante (IPSP) - CNR, UOS Bari, Via Amendola 122/D, 70126, Bari, Italy
| | - Giuseppina Mulè
- Istituto di Biomembrane, Bioenergetica e Biotecnologie Molecolari - CNR, Via Amendola 122/O, 70126, Bari, Italia
| | - Donato Gallitelli
- Dipartimento di Scienze del Suolo della Pianta e degli Alimenti, Università degli Studi di Bari "Aldo Moro", Via Amendola 165/A, 70126, Bari, Italy
- Istituto per la Protezione Sostenibile delle Piante (IPSP) - CNR, UOS Bari, Via Amendola 122/D, 70126, Bari, Italy
| | - Tiziana Mascia
- Dipartimento di Scienze del Suolo della Pianta e degli Alimenti, Università degli Studi di Bari "Aldo Moro", Via Amendola 165/A, 70126, Bari, Italy
- Istituto per la Protezione Sostenibile delle Piante (IPSP) - CNR, UOS Bari, Via Amendola 122/D, 70126, Bari, Italy
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Tzean Y, Chang HH, Tu TC, Hou BH, Chen HM, Chiu YS, Chou WY, Chang L, Yeh HH. Engineering Plant Resistance to Tomato Yellow Leaf Curl Thailand Virus Using a Phloem-Specific Promoter Expressing Hairpin RNA. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2020; 33:87-97. [PMID: 31638467 DOI: 10.1094/mpmi-06-19-0158-r] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Transgenic approaches employing RNA interference (RNAi) strategies have been successfully applied to generate desired traits in plants; however, variations between RNAi transgenic siblings and the ability to quickly apply RNAi resistance to diverse cultivars remain challenging. In this study, we assessed the promoter activity of a cauliflower mosaic virus 35S promoter (35S) and a phloem-specific promoter derived from rice tungro bacilliform virus (RTBV) and their efficacy to drive RNAi against the endogenous glutamate-1-semialdehyde aminotransferase gene (GSA) that acts as a RNAi marker, through chlorophyll synthesis inhibition, and against tomato yellow leaf curl Thailand virus (TYLCTHV), a begomovirus (family Geminiviridae) reported to be the prevalent cause of tomato yellow leaf curl disease (TYLCD) in Taiwan. Transgenic Nicotiana benthamiana expressing hairpin RNA of GSA driven by either the 35S or RTBV promoter revealed that RTBV::hpGSA induced stronger silencing along the vein and more uniformed silencing phenotype among its siblings than 35S::hpGSA. Analysis of transgenic N. benthamiana, 35S::hpTYLCTHV, and RTBV::hpTYLCTHV revealed that, although 35S::hpTYLCTHV generated a higher abundance of small RNA than RTBV::hpTYLCTHV, RTBV::hpTYLCTHV transgenic plants conferred better TYLCTHV resistance than 35S::hpTYLCTHV. Grafting of wild-type (WT) scions to TYLCTHV RNAi rootstocks allowed transferable TYLCTHV resistance to the scion. A TYLCTHV-inoculation assay showed that noninfected WT scions were only observed when grafted to RTBV::hpTYLCTHV rootstocks but not 35S::hpTYLCTHV nor WT rootstocks. Together, our findings demonstrate an approach that may be widely applied to efficiently confer TYLCD resistance.
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Affiliation(s)
- Yuh Tzean
- Agricultural Biotechnology Research Center, Academia Sinica, No. 128, Sec. 2, Academia Road, Nankang District, Taipei 11529, Taiwan
| | - Ho-Hsiung Chang
- Agricultural Biotechnology Research Center, Academia Sinica, No. 128, Sec. 2, Academia Road, Nankang District, Taipei 11529, Taiwan
| | - Tsui-Chin Tu
- Agricultural Biotechnology Research Center, Academia Sinica, No. 128, Sec. 2, Academia Road, Nankang District, Taipei 11529, Taiwan
| | - Bo-Han Hou
- Agricultural Biotechnology Research Center, Academia Sinica, No. 128, Sec. 2, Academia Road, Nankang District, Taipei 11529, Taiwan
| | - Ho-Ming Chen
- Agricultural Biotechnology Research Center, Academia Sinica, No. 128, Sec. 2, Academia Road, Nankang District, Taipei 11529, Taiwan
| | - Yi-Shu Chiu
- Agricultural Biotechnology Research Center, Academia Sinica, No. 128, Sec. 2, Academia Road, Nankang District, Taipei 11529, Taiwan
| | - Wei-Yi Chou
- Agricultural Biotechnology Research Center, Academia Sinica, No. 128, Sec. 2, Academia Road, Nankang District, Taipei 11529, Taiwan
| | - Li Chang
- Agricultural Biotechnology Research Center, Academia Sinica, No. 128, Sec. 2, Academia Road, Nankang District, Taipei 11529, Taiwan
| | - Hsin-Hung Yeh
- Agricultural Biotechnology Research Center, Academia Sinica, No. 128, Sec. 2, Academia Road, Nankang District, Taipei 11529, Taiwan
- Department of Plant Pathology and Microbiology, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd, Da'an District, Taipei 10617, Taiwan
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Suzuki T, Ikeda S, Kasai A, Taneda A, Fujibayashi M, Sugawara K, Okuta M, Maeda H, Sano T. RNAi-Mediated Down-Regulation of Dicer-Like 2 and 4 Changes the Response of 'Moneymaker' Tomato to Potato Spindle Tuber Viroid Infection from Tolerance to Lethal Systemic Necrosis, Accompanied by Up-Regulation of miR398, 398a-3p and Production of Excessive Amount of Reactive Oxygen Species. Viruses 2019; 11:v11040344. [PMID: 31013904 PMCID: PMC6521110 DOI: 10.3390/v11040344] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 04/08/2019] [Accepted: 04/10/2019] [Indexed: 12/14/2022] Open
Abstract
To examine the role of RNA silencing in plant defenses against viroids, a Dicer-like 2 and 4 (DCL2&4)–double knockdown transgenic tomato plant line, 72E, was created. The expression of endogenous SlDCL2s and SlDCL4 in line 72E decreased to about a half that of the empty cassette line, EC. When challenged with potato spindle tuber viroid (PSTVd), line 72E showed significantly higher levels of PSTVd accumulation early in the course of the infection and lethal systemic necrosis late in the infection. The size distribution of PSTVd-derived small RNAs was significantly different with the number of RNAs of 21 and 22 nucleotides (nt) in line 72E, at approximately 66.7% and 5% of those in line EC, respectively. Conversely, the numbers of 24 nt species increased by 1100%. Furthermore, expression of the stress-responsive microRNA species miR398 and miR398a-3p increased 770% and 868% in the PSTVd-infected line 72E compared with the PSTVd-infected EC. At the same time, the expression of cytosolic and chloroplast-localized Cu/Zn-superoxide dismutase 1 and 2 (SOD1 and SOD2) and the copper chaperon for SOD (CCS1) mRNAs, potential targets of miR398 or 398a-3p, decreased significantly in the PSTVd-infected line 72E leaves, showing necrosis. In concert with miR398 and 398a-3p, SODs control the detoxification of reactive oxygen species (ROS) generated in cells. Since high levels of ROS production were observed in PSTVd-infected line 72E plants, it is likely that the lack of full dicer-likes (DCL) activity in these plants made them unable to control excessive ROS production after PSTVd infection, as disruption in the ability of miR398 and miR398a-3p to regulate SODs resulted in the development of lethal systemic necrosis.
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Affiliation(s)
- Takahiro Suzuki
- Faculty of Agriculture and Life Science, Hirosaki University, Bunkyo-cho 3, Hirosaki 036-8561, Japan.
- Union Graduate School of Agricultural Sciences, Iwate University, 3-18-8 Ueda, Morioka, Iwate 020-8550, Japan.
| | - Sho Ikeda
- Faculty of Agriculture and Life Science, Hirosaki University, Bunkyo-cho 3, Hirosaki 036-8561, Japan.
| | - Atsushi Kasai
- Faculty of Agriculture and Life Science, Hirosaki University, Bunkyo-cho 3, Hirosaki 036-8561, Japan.
| | - Akito Taneda
- Graduate School of Science and Technology, Hirosaki University, Bunkyo-cho 3, Hirosaki 036-8561, Japan.
| | - Misato Fujibayashi
- Faculty of Agriculture and Life Science, Hirosaki University, Bunkyo-cho 3, Hirosaki 036-8561, Japan.
| | - Kohei Sugawara
- Faculty of Agriculture and Life Science, Hirosaki University, Bunkyo-cho 3, Hirosaki 036-8561, Japan.
| | - Maki Okuta
- Faculty of Agriculture and Life Science, Hirosaki University, Bunkyo-cho 3, Hirosaki 036-8561, Japan.
| | - Hayato Maeda
- Faculty of Agriculture and Life Science, Hirosaki University, Bunkyo-cho 3, Hirosaki 036-8561, Japan.
| | - Teruo Sano
- Faculty of Agriculture and Life Science, Hirosaki University, Bunkyo-cho 3, Hirosaki 036-8561, Japan.
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Chrysanthemum Stunt Viroid Resistance in Chrysanthemum. Viruses 2018; 10:v10120719. [PMID: 30562919 PMCID: PMC6315827 DOI: 10.3390/v10120719] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 12/12/2018] [Accepted: 12/13/2018] [Indexed: 12/17/2022] Open
Abstract
Chrysanthemum stunt viroid (CSVd) is one of the most severe threats in Chrysanthemum morifolium production. Over the last decade, several studies have reported the natural occurrence of CSVd resistance in chrysanthemum germplasms. Such CSVd-resistant germplasms are desirable for the stable production of chrysanthemum plants. Current surveys include finding new resistant chrysanthemum cultivars, breeding, and revealing resistant mechanisms. We review the progress, from discovery to current status, of CSVd-resistance studies, while introducing information on the improvement of associated inoculation and diagnostic techniques.
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Nabeshima T, Doi M, Hosokawa M. Comparative Analysis of Chrysanthemum Stunt Viroid Accumulation and Movement in Two Chrysanthemum ( Chrysanthemum morifolium) Cultivars with Differential Susceptibility to the Viroid Infection. FRONTIERS IN PLANT SCIENCE 2017; 8:1940. [PMID: 29250083 PMCID: PMC5715398 DOI: 10.3389/fpls.2017.01940] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Accepted: 10/27/2017] [Indexed: 06/07/2023]
Abstract
Chrysanthemum stunt viroid (CSVd) was inoculated into two chrysanthemum (Chrysanthemum morifolium) cultivars, the CSVd-susceptible cultivar Piato and the CSVd-resistant cultivar Mari Kazaguruma. For CSVd inoculation, grafting and Agrobacterium-mediated inoculation were used. In grafting experiments, CSVd was detectable in Mari Kazaguruma after grafting onto infected Piato, but after removal of infected rootstocks, CSVd could not be detected in the uppermost leaves. In agroinfection experiments, CSVd systemic infection was observed in Piato but not in Mari Kazaguruma. However, agro-inoculated leaves of Mari Kazaguruma accumulated circular CSVd RNA to levels equivalent to those in Piato at 7 days post-inoculation. In situ detection of CSVd in inoculated leaves revealed that CSVd was absent in phloem of Mari Kazaguruma, while CSVd strongly localized to this site in Piato. We hypothesize that CSVd resistance in Mari Kazaguruma relates not to CSVd replication but to CSVd movement in leaves.
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13
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Flores R, Navarro B, Kovalskaya N, Hammond RW, Di Serio F. Engineering resistance against viroids. Curr Opin Virol 2017; 26:1-7. [PMID: 28738223 DOI: 10.1016/j.coviro.2017.07.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 06/28/2017] [Accepted: 07/05/2017] [Indexed: 01/19/2023]
Abstract
Viroids, the smallest infectious agents endowed with autonomous replication, are tiny single-stranded circular RNAs (∼250 to 400nt) without protein-coding ability that, despite their simplicity, infect and often cause disease in herbaceous and woody plants of economic relevance. To mitigate the resulting losses, several strategies have been developed, the most effective of which include: firstly, search for naturally resistant cultivars and breeding for resistance, secondly, induced resistance by pre-infection with mild strains, thirdly, ribonucleases targeting double-stranded RNAs and catalytic antibodies endowed with intrinsic ribonuclease activity, fourthly, antisense, and sense, RNAs, fifthly, catalytic antisense RNAs derived from hammerhead ribozymes, and sixthly, hairpin RNAs and artificial small RNAs for RNA interference. The mechanisms underpinning these strategies, most of which have been implemented via genetic transformation, together with their present results and future potential, are the subject of this review.
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Affiliation(s)
- Ricardo Flores
- Instituto de Biología Molecular y Celular de Plantas (UPV-CSIC), Universidad Politécnica de Valencia, Valencia 46022, Spain.
| | - Beatriz Navarro
- Istituto per la Protezione Sostenibile delle Piante, Consiglio Nazionale delle Ricerche, 70126 Bari, Italy
| | - Natalia Kovalskaya
- Molecular Plant Pathology Laboratory, USDA-ARS-BARC, Beltsville, MD 20705, USA
| | - Rosemarie W Hammond
- Molecular Plant Pathology Laboratory, USDA-ARS-BARC, Beltsville, MD 20705, USA
| | - Francesco Di Serio
- Istituto per la Protezione Sostenibile delle Piante, Consiglio Nazionale delle Ricerche, 70126 Bari, Italy
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14
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Paces J, Nic M, Novotny T, Svoboda P. Literature review of baseline information to support the risk assessment of RNAi‐based GM plants. ACTA ACUST UNITED AC 2017. [PMCID: PMC7163844 DOI: 10.2903/sp.efsa.2017.en-1246] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Jan Paces
- Institute of Molecular Genetics of the Academy of Sciences of the Czech Republic (IMG)
| | | | | | - Petr Svoboda
- Institute of Molecular Genetics of the Academy of Sciences of the Czech Republic (IMG)
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15
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RNAi mediated inhibition of viroid infection in transgenic plants expressing viroid-specific small RNAs derived from various functional domains. Sci Rep 2015; 5:17949. [PMID: 26656294 PMCID: PMC4677296 DOI: 10.1038/srep17949] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Accepted: 11/09/2015] [Indexed: 12/25/2022] Open
Abstract
Previous attempts to develop RNAi-mediated viroid-resistant transgenic plants using nearly full-length Potato spindle tuber viroid (PSTVd) hairpin RNA (hpRNA) were successful; however unusual phenotypes resembling viroid infection occurred. Therefore, in the present work, transgenic Nicotiana benthamiana lines expressing both partial and truncated versions of PSTVd hpRNA were developed. Specifically, seven partial or truncated versions of PSTVd sequences were selected according to the hotspots of both PSTVd-sRNAs and functional domains of the PSTVd. A total of 21 transgenic lines Nicotiana benthamiana were developed under the control of either the CaMV-35S or the CoYMV promoters. All of the transgenic lines established here were monitored for the induction of phenotypic changes, for PSTVd-sRNA expression and for the resistance against PSTVd infection. Additionally, this study demonstrates the use of inverted repeat construct sequences as short as 26- to -49 nucleotides for both the efficient expression of the PSTVd-sRNA and the inhibition of PSTVd infection.
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16
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Grafting on a Non-Transgenic Tolerant Tomato Variety Confers Resistance to the Infection of a Sw5-Breaking Strain of Tomato spotted wilt virus via RNA Silencing. PLoS One 2015. [PMID: 26496695 DOI: 10.1371/journal.pone.0141319.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
RNA silencing controls endogenous gene expression and drives defensive reactions against invasive nucleic acids like viruses. In plants, it has been demonstrated that RNA silencing can be transmitted through grafting between scions and silenced rootstocks to attenuate virus and viroid accumulation in the scions. This has been obtained mostly using transgenic plants, which may be a drawback in current agriculture. In the present study, we examined the dynamics of infection of a resistance-breaking strain of Tomato spotted wilt virus (RB-TSWV) through the graft between an old Apulian (southern Italy) tomato variety, denoted Sl-Ma, used as a rootstock and commercial tomato varieties used as scions. In tests with non-grafted plants, Sl-Ma showed resistance to the RB-TSWV infection as viral RNA accumulated at low levels and plants recovered from disease symptoms by 21 days post inoculation. The resistance trait was transmitted to the otherwise highly susceptible tomato genotypes grafted onto Sl-Ma. The results from the analysis of small RNAs hallmark genes involved in RNA silencing and virus-induced gene silencing suggest that RNA silencing is involved in the resistance showed by Sl-Ma against RB-TSWV and in scions grafted on this rootstock. The results from self-grafted susceptible tomato varieties suggest also that RNA silencing is enhanced by the graft itself. We can foresee interesting practical implications of the approach described in this paper.
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17
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Spanò R, Mascia T, Kormelink R, Gallitelli D. Grafting on a Non-Transgenic Tolerant Tomato Variety Confers Resistance to the Infection of a Sw5-Breaking Strain of Tomato spotted wilt virus via RNA Silencing. PLoS One 2015; 10:e0141319. [PMID: 26496695 PMCID: PMC4619829 DOI: 10.1371/journal.pone.0141319] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 10/07/2015] [Indexed: 02/03/2023] Open
Abstract
RNA silencing controls endogenous gene expression and drives defensive reactions against invasive nucleic acids like viruses. In plants, it has been demonstrated that RNA silencing can be transmitted through grafting between scions and silenced rootstocks to attenuate virus and viroid accumulation in the scions. This has been obtained mostly using transgenic plants, which may be a drawback in current agriculture. In the present study, we examined the dynamics of infection of a resistance-breaking strain of Tomato spotted wilt virus (RB-TSWV) through the graft between an old Apulian (southern Italy) tomato variety, denoted Sl-Ma, used as a rootstock and commercial tomato varieties used as scions. In tests with non-grafted plants, Sl-Ma showed resistance to the RB-TSWV infection as viral RNA accumulated at low levels and plants recovered from disease symptoms by 21 days post inoculation. The resistance trait was transmitted to the otherwise highly susceptible tomato genotypes grafted onto Sl-Ma. The results from the analysis of small RNAs hallmark genes involved in RNA silencing and virus-induced gene silencing suggest that RNA silencing is involved in the resistance showed by Sl-Ma against RB-TSWV and in scions grafted on this rootstock. The results from self-grafted susceptible tomato varieties suggest also that RNA silencing is enhanced by the graft itself. We can foresee interesting practical implications of the approach described in this paper.
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Affiliation(s)
- Roberta Spanò
- Dipartimento di Scienze del Suolo della Pianta e Degli Alimenti, Università degli Studi di Bari Aldo Moro, Via Amendola 165/A, Bari, Italy
- Istituto di Virologia vegetale del CNR, Unità Operativa di Supporto di Bari, Via Amendola 165/A, Bari, Italy
| | - Tiziana Mascia
- Dipartimento di Scienze del Suolo della Pianta e Degli Alimenti, Università degli Studi di Bari Aldo Moro, Via Amendola 165/A, Bari, Italy
- Istituto di Virologia vegetale del CNR, Unità Operativa di Supporto di Bari, Via Amendola 165/A, Bari, Italy
- * E-mail:
| | - Richard Kormelink
- Laboratory of Virology, Wageningen University, Droevendaalsesteeg 1, Wageningen, The Netherlands
| | - Donato Gallitelli
- Dipartimento di Scienze del Suolo della Pianta e Degli Alimenti, Università degli Studi di Bari Aldo Moro, Via Amendola 165/A, Bari, Italy
- Istituto di Virologia vegetale del CNR, Unità Operativa di Supporto di Bari, Via Amendola 165/A, Bari, Italy
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18
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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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19
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Sangha JS, Kandasamy S, Khan W, Bahia NS, Singh RP, Critchley AT, Prithiviraj B. λ-Carrageenan Suppresses Tomato Chlorotic Dwarf Viroid (TCDVd) Replication and Symptom Expression in Tomatoes. Mar Drugs 2015; 13:2875-89. [PMID: 26006710 PMCID: PMC4446610 DOI: 10.3390/md13052875] [Citation(s) in RCA: 16] [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: 02/27/2015] [Revised: 04/18/2015] [Accepted: 04/27/2015] [Indexed: 11/25/2022] Open
Abstract
The effect of carrageenans on tomato chlorotic dwarf viroid (TCDVd) replication and symptom expression was studied. Three-week-old tomato plants were spray-treated with iota(ɩ)-, lambda(λ)-, and kappa(κ)-carrageenan at 1 g·L-1 and inoculated with TCDVd after 48 h. The λ-carrageenan significantly suppressed viroid symptom expression after eight weeks of inoculation, only 28% plants showed distinctive bunchy-top symptoms as compared to the 82% in the control group. Viroid concentration was reduced in the infected shoot cuttings incubated in λ-carrageenan amended growth medium. Proteome analysis revealed that 16 tomato proteins were differentially expressed in the λ-carrageenan treated plants. Jasmonic acid related genes, allene oxide synthase (AOS) and lipoxygenase (LOX), were up-regulated in λ-carrageenan treatment during viroid infection. Taken together, our results suggest that λ-carrageenan induced tomato defense against TCDVd, which was partly jasmonic acid (JA) dependent, and that it could be explored in plant protection against viroid infection.
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Affiliation(s)
- Jatinder S Sangha
- Department of Environmental Sciences, Faculty of Agriculture, Dalhousie University, P.O. Box 550, Truro, NS B2N 5E3, Canada.
| | - Saveetha Kandasamy
- Department of Environmental Sciences, Faculty of Agriculture, Dalhousie University, P.O. Box 550, Truro, NS B2N 5E3, Canada.
| | - Wajahatullah Khan
- Basic Sciences Department, King Saud Bin Abdul Aziz University for Health Sciences, P.O. Box 22490, Riyadh 11426, Saudi Arabia.
| | - Navratan Singh Bahia
- Department of Environmental Sciences, Faculty of Agriculture, Dalhousie University, P.O. Box 550, Truro, NS B2N 5E3, Canada.
| | - Rudra P Singh
- Agriculture and Agri-Food Canada, 850 Lincoln Rd., Fredericton, NB E3B 4Z7, Canada.
| | - Alan T Critchley
- Acadian Seaplants Limited, 30 Brown Avenue, Dartmouth, NS B3B 1X8, Canada.
| | - Balakrishnan Prithiviraj
- Department of Environmental Sciences, Faculty of Agriculture, Dalhousie University, P.O. Box 550, Truro, NS B2N 5E3, Canada.
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20
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Viroids, the simplest RNA replicons: How they manipulate their hosts for being propagated and how their hosts react for containing the infection. Virus Res 2015; 209:136-45. [PMID: 25738582 DOI: 10.1016/j.virusres.2015.02.027] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 02/23/2015] [Accepted: 02/23/2015] [Indexed: 12/31/2022]
Abstract
The discovery of viroids about 45 years ago heralded a revolution in Biology: small RNAs comprising around 350 nt were found to be able to replicate autonomously-and to incite diseases in certain plants-without encoding proteins, fundamental properties discriminating these infectious agents from viruses. The initial focus on the pathological effects usually accompanying infection by viroids soon shifted to their molecular features-they are circular molecules that fold upon themselves adopting compact secondary conformations-and then to how they manipulate their hosts to be propagated. Replication of viroids-in the nucleus or chloroplasts through a rolling-circle mechanism involving polymerization, cleavage and circularization of RNA strands-dealt three surprises: (i) certain RNA polymerases are redirected to accept RNA instead of their DNA templates, (ii) cleavage in chloroplastic viroids is not mediated by host enzymes but by hammerhead ribozymes, and (iii) circularization in nuclear viroids is catalyzed by a DNA ligase redirected to act upon RNA substrates. These enzymes (and ribozymes) are most probably assisted by host proteins, including transcription factors and RNA chaperones. Movement of viroids, first intracellularly and then to adjacent cells and distal plant parts, has turned out to be a tightly regulated process in which specific RNA structural motifs play a crucial role. More recently, the advent of RNA silencing has brought new views on how viroids may cause disease and on how their hosts react to contain the infection; additionally, viroid infection may be restricted by other mechanisms. Representing the lowest step on the biological size scale, viroids have also attracted considerable interest to get a tentative picture of the essential characteristics of the primitive replicons that populated the postulated RNA world.
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21
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Dalakouras A, Dadami E, Wassenegger M. Engineering viroid resistance. Viruses 2015; 7:634-46. [PMID: 25674769 PMCID: PMC4353907 DOI: 10.3390/v7020634] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 01/30/2015] [Indexed: 12/31/2022] Open
Abstract
Viroids are non-encapsidated, non-coding, circular, single-stranded RNAs (ssRNAs). They are classified into the families Pospiviroidae and Avsunviroidae, whose members replicate in the nucleus and chloroplast of plant cells, respectively. Viroids have a wide host range, including crop and ornamental plants, and can cause devastating diseases with significant economic losses. Thus, several viroids are world-wide, classified as quarantine pathogens and, hence, there is an urgent need for the development of robust antiviroid strategies. RNA silencing-based technologies seem to be a promising tool in this direction. Here, we review the recent advances concerning the complex interaction of viroids with the host's RNA silencing machinery, evaluate past and present antiviroid approaches, and finally suggest alternative strategies that could potentially be employed in the future in order to achieve transgenic and non-transgenic viroid-free plants.
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Affiliation(s)
- Athanasios Dalakouras
- RLP AgroScience GmbH, AIPlanta-Institute for Plant Research, Neustadt, 67435, Germany.
| | - Elena Dadami
- RLP AgroScience GmbH, AIPlanta-Institute for Plant Research, Neustadt, 67435, Germany.
| | - Michael Wassenegger
- RLP AgroScience GmbH, AIPlanta-Institute for Plant Research, Neustadt, Germany and Centre for Organisational Studies (COS) Heidelberg, University of Heidelberg, Heidelberg, 69120, Germany.
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22
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Dalakouras A, Dadami E, Bassler A, Zwiebel M, Krczal G, Wassenegger M. Replicating Potato spindle tuber viroid mediates de novo methylation of an intronic viroid sequence but no cleavage of the corresponding pre-mRNA. RNA Biol 2015; 12:268-75. [PMID: 25826660 PMCID: PMC4615544 DOI: 10.1080/15476286.2015.1017216] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Revised: 01/05/2015] [Accepted: 01/05/2015] [Indexed: 10/23/2022] Open
Abstract
In plants, Potato spindle tuber viroid (PSTVd) replication triggers post-transcriptional gene silencing (PTGS) and RNA-directed DNA methylation (RdDM) of homologous RNA and DNA sequences, respectively. PTGS predominantly occurs in the cytoplasm, but nuclear PTGS has been also reported. In this study, we investigated whether the nuclear replicating PSTVd is able to trigger nuclear PTGS. Transgenic tobacco plants carrying cytoplasmic and nuclear PTGS sensor constructs were PSTVd-infected resulting in the generation of abundant PSTVd-derived small interfering RNAs (vd-siRNAs). Northern blot analysis revealed that, in contrast to the cytoplasmic sensor, the nuclear sensor transcript was not targeted for RNA degradation. Bisulfite sequencing analysis showed that the nuclear PTGS sensor transgene was efficiently targeted for RdDM. Our data suggest that PSTVd fails to trigger nuclear PTGS, and that RdDM and nuclear PTGS are not necessarily coupled.
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Affiliation(s)
| | - Elena Dadami
- RLP AgroScience GmbH; AlPlanta-Institute for Plant Research; Neustadt, Germany
| | - Alexandra Bassler
- RLP AgroScience GmbH; AlPlanta-Institute for Plant Research; Neustadt, Germany
| | - Michele Zwiebel
- RLP AgroScience GmbH; AlPlanta-Institute for Plant Research; Neustadt, Germany
| | - Gabi Krczal
- RLP AgroScience GmbH; AlPlanta-Institute for Plant Research; Neustadt, Germany
| | - Michael Wassenegger
- RLP AgroScience GmbH; AlPlanta-Institute for Plant Research; Neustadt, Germany
- Centre for Organismal Studies (COS) Heidelberg; University of Heidelberg; Heidelberg, Germany
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23
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Zhao D, Song GQ. Rootstock-to-scion transfer of transgene-derived small interfering RNAs and their effect on virus resistance in nontransgenic sweet cherry. PLANT BIOTECHNOLOGY JOURNAL 2014; 12:1319-28. [PMID: 25132092 DOI: 10.1111/pbi.12243] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Revised: 07/13/2014] [Accepted: 07/20/2014] [Indexed: 05/03/2023]
Abstract
Small interfering RNAs (siRNAs) are silencing signals in plants. Virus-resistant transgenic rootstocks developed through siRNA-mediated gene silencing may enhance virus resistance of nontransgenic scions via siRNAs transported from the transgenic rootstocks. However, convincing evidence of rootstock-to-scion movement of siRNAs of exogenous genes in woody plants is still lacking. To determine whether exogenous siRNAs can be transferred, nontransgenic sweet cherry (scions) was grafted on transgenic cherry rootstocks (TRs), which was transformed with an RNA interference (RNAi) vector expressing short hairpin RNAs of the genomic RNA3 of Prunus necrotic ringspot virus (PNRSV-hpRNA). Small RNA sequencing was conducted using bud tissues of TRs and those of grafted (rootstock/scion) trees, locating at about 1.2 m above the graft unions. Comparison of the siRNA profiles revealed that the PNRSV-hpRNA was efficient in producing siRNAs and eliminating PNRSV in the TRs. Furthermore, our study confirmed, for the first time, the long-distance (1.2 m) transfer of PNRSV-hpRNA-derived siRNAs from the transgenic rootstock to the nontransgenic scion in woody plants. Inoculation of nontransgenic scions with PNRSV revealed that the transferred siRNAs enhanced PNRSV resistance of the scions grafted on the TRs. Collectively, these findings provide the foundation for 'using transgenic rootstocks to produce products of nontransgenic scions in fruit trees'.
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Affiliation(s)
- Dongyan Zhao
- Plant Biotechnology Resource and Outreach Center, Department of Horticulture, Michigan State University, East Lansing, MI, USA
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24
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Kovalskaya N, Hammond RW. Molecular biology of viroid-host interactions and disease control strategies. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2014; 228:48-60. [PMID: 25438785 DOI: 10.1016/j.plantsci.2014.05.006] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 03/26/2014] [Accepted: 05/14/2014] [Indexed: 06/04/2023]
Abstract
Viroids are single-stranded, covalently closed, circular, highly structured noncoding RNAs that cause disease in several economically important crop plants. They replicate autonomously and move systemically in host plants with the aid of the host machinery. In addition to symptomatic infections, viroids also cause latent infections where there is no visual evidence of infection in the host; however, transfer to a susceptible host can result in devastating disease. While there are non-hosts for viroids, no naturally occurring durable resistance has been observed in most host species. Current effective control methods for viroid diseases include detection and eradication, and cultural controls. In addition, heat or cold therapy combined with meristem tip culture has been shown to be effective for elimination of viroids for some viroid-host combinations. An understanding of viroid-host interactions, host susceptibility, and non-host resistance could provide guidance for the design of viroid-resistant plants. Efforts to engineer viroid resistance into host species have been underway for several years, and include the use of antisense RNA, antisense RNA plus ribozymes, a dsRNase, and siRNAs, among others. The results of those efforts and the challenges associated with creating viroid resistant plants are summarized in this review.
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Affiliation(s)
- Natalia Kovalskaya
- USDA ARS BARC Molecular Plant Pathology Laboratory, Beltsville, MD 20705, USA
| | - Rosemarie W Hammond
- USDA ARS BARC Molecular Plant Pathology Laboratory, Beltsville, MD 20705, USA.
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25
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Zhao D, Song GQ. High-throughput sequencing as an effective approach in profiling small RNAs derived from a hairpin RNA expression vector in woody plants. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2014; 228:39-47. [PMID: 25438784 DOI: 10.1016/j.plantsci.2014.02.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Revised: 02/21/2014] [Accepted: 02/25/2014] [Indexed: 06/04/2023]
Abstract
Hairpin RNA (hpRNA)-mediated gene silencing has proved to be an efficient approach to develop virus-resistant transgenic plants. To characterize small RNA molecules (sRNAs) derived from an hpRNA expression vector in transgenic cherry rootstock plants, we conducted small RNA sequencing of (1) a transgenic rootstock containing an inverted repeat of the partial coat protein of Prunus necrotic ring spot virus (PNRSV-hpRNA); (2) a nontransgenic rootstock; and (3) a PNRSV-infected sweet cherry plant. Analysis of the PNRSV sRNA pools indicated that 24-nt (nucleotide) small interfering RNAs (siRNAs) were the most prevalent sRNAs in the transgenic rootstock whereas the most abundant sRNAs in the PNRSV-infected nontransgenic rootstock were 21-nt siRNAs. In addition, the 24-nt siRNAs of the PNRSV-hpRNA were more abundant on the sense strand than those on the antisense strand in the transgenic rootstock. In contrast, preference in generating PNRSV sRNAs, ranging from 19-nt to 30-nt for sense and antisense strands, was not distinct in the PNRSV-infected nontransgenic sweet cherry. Taken together, this is the first report on profiling hpRNA-derived sRNAs in woody plants using high-throughput sequencing technology, which is an efficient way to verify the presence/absence, the abundance, and the sequence features of certain sRNAs.
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Affiliation(s)
- Dongyan Zhao
- Plant Biotechnology Resource and Outreach Center, Department of Horticulture, Michigan State University, East Lansing, MI 48824, USA.
| | - Guo-Qing Song
- Plant Biotechnology Resource and Outreach Center, Department of Horticulture, Michigan State University, East Lansing, MI 48824, USA.
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What has been happening with viroids? Virus Genes 2014; 49:175-84. [DOI: 10.1007/s11262-014-1110-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Accepted: 08/18/2014] [Indexed: 12/18/2022]
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Ivanova D, Milev I, Vachev T, Baev V, Yahubyan G, Minkov G, Gozmanova M. Small RNA analysis of Potato spindle tuber viroid infected Phelipanche ramosa. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2014; 74:276-282. [PMID: 24326144 DOI: 10.1016/j.plaphy.2013.11.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Accepted: 11/18/2013] [Indexed: 06/03/2023]
Abstract
Plants defend themselves against virus/viroid infection by induction of a mechanism of viral RNA degradation or translation inhibition. This is achieved by the production of small RNAs referred to as small interfering RNAs and microRNA, the key molecules in establishment of RNA directed silencing. Potato Spindle Tuber Viroid (PSTVd) was the first viroid species to be identified as naturally infecting potato, and it was found to infect many other crop species, wild and ornamental plants. Recently the experimental host range of PSTVd was extended with the root non-photosynthetic parasitic weed--Phelipanche ramosa (L) Pomel. Here we examined the small RNA population in P. ramosa infected with PSTVd and we observed the presence of PSTVd derived small RNAs. The hotspot regions for production of those PSTVd specific small RNAs were defined by their mapping on the viroid genome sequence. Further, we evaluated the expression levels of selected conserved microRNA families in the viroid infected P. ramosa. Upon infection, two members of miRNA395 family were significantly accumulated, while several members of miRNA390, miRNA396, miRNA319, miRNA166, miRNA167 and miRNA159 were strongly down-regulated. All these findings imply the involvement of various small RNA classes in the P. ramosa response to PSTVd infection.
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Affiliation(s)
- Desislava Ivanova
- Department of Plant Physiology and Molecular Biology, University of Plovdiv 24, Tsar Assen Str., 4000 Plovdiv, Bulgaria; IMBB FORTH, Nikolau Plastira 100, P.O. Box 1385, GR-70013 Heraklion, Crete, Greece; Biology Department, University of Crete, Greece, Vasilika Vouton, P.O. Box 2208, 71409 Heraklion, Crete, Greece
| | - Ivan Milev
- Department of Plant Physiology and Molecular Biology, University of Plovdiv 24, Tsar Assen Str., 4000 Plovdiv, Bulgaria
| | - Tihomir Vachev
- Department of Plant Physiology and Molecular Biology, University of Plovdiv 24, Tsar Assen Str., 4000 Plovdiv, Bulgaria
| | - Vesselin Baev
- Department of Plant Physiology and Molecular Biology, University of Plovdiv 24, Tsar Assen Str., 4000 Plovdiv, Bulgaria
| | - Galina Yahubyan
- Department of Plant Physiology and Molecular Biology, University of Plovdiv 24, Tsar Assen Str., 4000 Plovdiv, Bulgaria
| | - Georgi Minkov
- Department of Plant Physiology and Molecular Biology, University of Plovdiv 24, Tsar Assen Str., 4000 Plovdiv, Bulgaria
| | - Mariyana Gozmanova
- Department of Plant Physiology and Molecular Biology, University of Plovdiv 24, Tsar Assen Str., 4000 Plovdiv, Bulgaria.
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Kondo K, Nakamura K. [Scientific review on novel genome editing techniques]. Food Hygiene and Safety Science (Shokuhin Eiseigaku Zasshi) 2014; 55:231-46. [PMID: 25743586 DOI: 10.3358/shokueishi.55.231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Ma C, Lu Y, Bai S, Zhang W, Duan X, Meng D, Wang Z, Wang A, Zhou Z, Li T. Cloning and characterization of miRNAs and their targets, including a novel miRNA-targeted NBS-LRR protein class gene in apple (Golden Delicious). MOLECULAR PLANT 2014; 7:218-30. [PMID: 23880633 DOI: 10.1093/mp/sst101] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
MicroRNA (miRNA) has emerged as an important regulator of gene expression in plants. 146 miRNAs were identified from apple (Malus domestica cv. Golden Delicious) by bioinformatic analysis and RNA library sequencing. From these, 135 were conserved and 11 were novel miRNAs. Target analysis predicted one of the novel miRNAs, Md-miRLn11 (Malus domestica microRNA Ln11), targeted an apple nucleotide-binding site (NBS)-leucine-rich repeat (LRR) class protein coding gene (Md-NBS). 5' RACE assay confirmed the ability of Md-miRLn11 to cleave Md-NBS at the 11-12-nt position. Analysis of the expression of Md-miRLn11 and Md-NBS during the optimum invasion period in 40 apple varieties showed that the expression of Md-NBS gene in resistant varieties is higher than in susceptible varieties, with an inverse pattern for Md-miRLn11. Seedlings from the resistant apple variety 'JiGuan' were used to carry out an Agrobacterium infiltration assay, and then inoculated with the apple leaf spot disease. The result showed a clear decline of disease resistance in JiGuan apples. In contrast, the susceptible variety 'FuJi' infiltrated with the Md-NBS gene showed a significant increase in disease resistance. Based on the above results, we propose that Md-miRLn11 regulates Md-NBS gene expression in particular under the condition of pathogen infection, and that the Md-miRLn11 targeting P-loop site may regulate many NBS-LRR protein class genes in woody plants.
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Affiliation(s)
- Chao Ma
- Laboratory of Fruit Cell and Molecular Breeding, China Agricultural University, Beijing 100193, China
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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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