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Azizi A, Del Río Mendoza LE. Effective Control of Sclerotinia Stem Rot in Canola Plants Through Application of Exogenous Hairpin RNA of Multiple Sclerotinia sclerotiorum Genes. PHYTOPATHOLOGY 2024; 114:1000-1010. [PMID: 38506733 DOI: 10.1094/phyto-10-23-0395-kc] [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: 03/21/2024]
Abstract
Sclerotinia stem rot is a globally destructive plant disease caused by Sclerotinia sclerotiorum. Current management of Sclerotinia stem rot primarily relies on chemical fungicides and crop rotation, raising environmental concerns. In this study, we developed an eco-friendly RNA bio-fungicide targeting S. sclerotiorum. Six S. sclerotiorum genes were selected for double-stranded RNA (dsRNA) synthesis. Four genes, a chitin-binding domain, mitogen-activated protein kinase, oxaloacetate acetylhydrolase, and abhydrolase-3, were combined to express hairpin RNA in Escherichia coli HT115. The effect of application of total RNA extracted from E. coli HT115 expressing hairpin RNA on disease progressive and necrosis lesions was evaluated. Gene expression analysis using real-time PCR showed silencing of the target genes using 5 ng/µl of dsRNA in a fungal liquid culture. A detached leaf assay and greenhouse application of dsRNA on canola stem and leaves showed variation in the reduction of necrosis symptoms by dsRNA of different genes, with abhydrolase-3 being the most effective. The dsRNA from a combination of four genes reduced disease severity significantly (P = 0.01). Plants sprayed with hairpin RNA from four genes had lesions that were almost 30% smaller than those of plants treated with abhydrolase-3 alone, in lab and greenhouse assays. The results of this study highlight the potential of RNA interference to manage diseases caused by S. sclerotiorum; however, additional research is necessary to optimize its efficacy.
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Affiliation(s)
- Abdolbaset Azizi
- Department of Plant Pathology, North Dakota State University, ND, U.S.A
- Department of Plant Protection, University of Kurdistan, Sanandaj, Iran
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2
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Gruber C, Gursinsky T, Gago-Zachert S, Pantaleo V, Behrens SE. Effective Antiviral Application of Antisense in Plants by Exploiting Accessible Sites in the Target RNA. Int J Mol Sci 2023; 24:17153. [PMID: 38138982 PMCID: PMC10743417 DOI: 10.3390/ijms242417153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 12/01/2023] [Accepted: 12/03/2023] [Indexed: 12/24/2023] Open
Abstract
Antisense oligodeoxynucleotides (ASOs) have long been used to selectively inhibit or modulate gene expression at the RNA level, and some ASOs are approved for clinical use. However, the practicability of antisense technologies remains limited by the difficulty of reliably predicting the sites accessible to ASOs in complex folded RNAs. Recently, we applied a plant-based method that reproduces RNA-induced RNA silencing in vitro to reliably identify sites in target RNAs that are accessible to small interfering RNA (siRNA)-guided Argonaute endonucleases. Here, we show that this method is also suitable for identifying ASOs that are effective in DNA-induced RNA silencing by RNases H. We show that ASOs identified in this way that target a viral genome are comparably effective in protecting plants from infection as siRNAs with the corresponding sequence. The antiviral activity of the ASOs could be further enhanced by chemical modification. This led to two important conclusions: siRNAs and ASOs that can effectively knock down complex RNA molecules can be identified using the same approach, and ASOs optimized in this way could find application in crop protection. The technology developed here could be useful not only for effective RNA silencing in plants but also in other organisms.
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Affiliation(s)
- Cornelia Gruber
- Institute of Biochemistry and Biotechnology, Section Microbial Biotechnology, Martin Luther University Halle-Wittenberg, D-06120 Halle (Saale), Germany; (C.G.); (T.G.); (S.G.-Z.)
| | - Torsten Gursinsky
- Institute of Biochemistry and Biotechnology, Section Microbial Biotechnology, Martin Luther University Halle-Wittenberg, D-06120 Halle (Saale), Germany; (C.G.); (T.G.); (S.G.-Z.)
| | - Selma Gago-Zachert
- Institute of Biochemistry and Biotechnology, Section Microbial Biotechnology, Martin Luther University Halle-Wittenberg, D-06120 Halle (Saale), Germany; (C.G.); (T.G.); (S.G.-Z.)
| | - Vitantonio Pantaleo
- Institute for Sustainable Plant Protection, Department of Biology, Agricultural and Food Sciences National Research Council, Bari Unit, I-70126 Bari, Italy;
| | - Sven-Erik Behrens
- Institute of Biochemistry and Biotechnology, Section Microbial Biotechnology, Martin Luther University Halle-Wittenberg, D-06120 Halle (Saale), Germany; (C.G.); (T.G.); (S.G.-Z.)
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Liu S, Han Y, Li WX, Ding SW. Infection Defects of RNA and DNA Viruses Induced by Antiviral RNA Interference. Microbiol Mol Biol Rev 2023; 87:e0003522. [PMID: 37052496 PMCID: PMC10304667 DOI: 10.1128/mmbr.00035-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/14/2023] Open
Abstract
Immune recognition of viral genome-derived double-stranded RNA (dsRNA) molecules and their subsequent processing into small interfering RNAs (siRNAs) in plants, invertebrates, and mammals trigger specific antiviral immunity known as antiviral RNA interference (RNAi). Immune sensing of viral dsRNA is sequence-independent, and most regions of viral RNAs are targeted by virus-derived siRNAs which extensively overlap in sequence. Thus, the high mutation rates of viruses do not drive immune escape from antiviral RNAi, in contrast to other mechanisms involving specific virus recognition by host immune proteins such as antibodies and resistance (R) proteins in mammals and plants, respectively. Instead, viruses actively suppress antiviral RNAi at various key steps with a group of proteins known as viral suppressors of RNAi (VSRs). Some VSRs are so effective in virus counter-defense that potent inhibition of virus infection by antiviral RNAi is undetectable unless the cognate VSR is rendered nonexpressing or nonfunctional. Since viral proteins are often multifunctional, resistance phenotypes of antiviral RNAi are accurately defined by those infection defects of VSR-deletion mutant viruses that are efficiently rescued by host deficiency in antiviral RNAi. Here, we review and discuss in vivo infection defects of VSR-deficient RNA and DNA viruses resulting from the actions of host antiviral RNAi in model systems.
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Affiliation(s)
- Si Liu
- Department of Microbiology & Plant Pathology, University of California, Riverside, California, USA
- Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, California, USA
| | - Yanhong Han
- Vector-borne Virus Research Center, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
| | - Wan-Xiang Li
- Department of Microbiology & Plant Pathology, University of California, Riverside, California, USA
- Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, California, USA
| | - Shou-Wei Ding
- Department of Microbiology & Plant Pathology, University of California, Riverside, California, USA
- Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, California, USA
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Chang T, Hunt BPV, Hirai J, Suttle CA. Divergent RNA viruses infecting sea lice, major ectoparasites of fish. PLoS Pathog 2023; 19:e1011386. [PMID: 37347729 DOI: 10.1371/journal.ppat.1011386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 04/25/2023] [Indexed: 06/24/2023] Open
Abstract
Sea lice, the major ectoparasites of fish, have significant economic impacts on wild and farmed finfish, and have been implicated in the decline of wild salmon populations. As blood-feeding arthropods, sea lice may also be reservoirs for viruses infecting fish. However, except for two groups of negative-strand RNA viruses within the order Mononegavirales, nothing is known about viruses of sea lice. Here, we used transcriptomic data from three key species of sea lice (Lepeophtheirus salmonis, Caligus clemensi, and Caligus rogercresseyi) to identify 32 previously unknown RNA viruses. The viruses encompassed all the existing phyla of RNA viruses, with many placed in deeply branching lineages that likely represent new families and genera. Importantly, the presence of canonical virus-derived small interfering RNAs (viRNAs) indicates that most of these viruses infect sea lice, even though in some cases their closest classified relatives are only known to infect plants or fungi. We also identified both viRNAs and PIWI-interacting RNAs (piRNAs) from sequences of a bunya-like and two qin-like viruses in C. rogercresseyi. Our analyses showed that most of the viruses found in C. rogercresseyi occurred in multiple life stages, spanning from planktonic to parasitic stages. Phylogenetic analysis revealed that many of the viruses infecting sea lice were closely related to those that infect a wide array of eukaryotes with which arthropods associate, including fungi and parasitic tapeworms, implying that over evolutionary time there has been cross-phylum and cross-kingdom switching of viruses between arthropods and other eukaryotes. Overall, this study greatly expands our view of virus diversity in crustaceans, identifies viruses that infect and replicate in sea lice, and provides evidence that over evolutionary time, viruses have switched between arthropods and eukaryotic hosts in other phyla and kingdoms.
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Affiliation(s)
- Tianyi Chang
- Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, Canada
| | - Brian P V Hunt
- Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, Canada
- Institute for the Oceans and Fisheries, University of British Columbia, Vancouver, Canada
- Hakai Institute, Campbell River, Canada
| | - Junya Hirai
- Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Japan
| | - Curtis A Suttle
- Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, Canada
- Institute for the Oceans and Fisheries, University of British Columbia, Vancouver, Canada
- Hakai Institute, Campbell River, Canada
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
- Department of Botany, University of British Columbia, Vancouver, Canada
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Schaible P, Bethge W, Lengerke C, Haraszti RA. RNA Therapeutics for Improving CAR T-cell Safety and Efficacy. Cancer Res 2023; 83:354-362. [PMID: 36512627 PMCID: PMC7614194 DOI: 10.1158/0008-5472.can-22-2155] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 11/02/2022] [Accepted: 12/09/2022] [Indexed: 12/15/2022]
Abstract
Autologous chimeric antigen receptor (CAR) T cells have recently emerged as potent tools in the fight against cancer, with promising therapeutic efficacy against hematological malignancies. However, several limitations hamper their widespread clinical use, including availability of target antigen, severe toxic effects, primary and secondary resistance, heterogeneous quality of autologous T cells, variable persistence, and low activity against solid tumors. Development of allogeneic off-the-shelf CAR T cells could help address some of these limitations but is impeded by alloimmunity with either rejection and limited expansion of allo-CAR T cells or CAR T cells versus host reactions. RNA therapeutics, such as small interfering RNAs, microRNAs, and antisense oligonucleotides, are able to silence transcripts in a sequence-specific and proliferation-sensitive way, which may offer a way to overcome some of the challenges facing CAR T-cell development and clinical utility. Here, we review how different RNA therapeutics or a combination of RNA therapeutics and genetic engineering could be harnessed to improve the safety and efficacy of autologous and allogeneic CAR T-cell therapy.
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Affiliation(s)
- Philipp Schaible
- Department of Internal Medicine II, Hematology, Oncology, Clinical Immunology and Rheumatology, University Hospital Tübingen, Tübingen, Germany
| | - Wolfgang Bethge
- Department of Internal Medicine II, Hematology, Oncology, Clinical Immunology and Rheumatology, University Hospital Tübingen, Tübingen, Germany
| | - Claudia Lengerke
- Department of Internal Medicine II, Hematology, Oncology, Clinical Immunology and Rheumatology, University Hospital Tübingen, Tübingen, Germany
| | - Reka Agnes Haraszti
- Department of Internal Medicine II, Hematology, Oncology, Clinical Immunology and Rheumatology, University Hospital Tübingen, Tübingen, Germany
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Akbarimotlagh M, Azizi A, Shams-Bakhsh M, Jafari M, Ghasemzadeh A, Palukaitis P. Critical points for the design and application of RNA silencing constructs for plant virus resistance. Adv Virus Res 2023; 115:159-203. [PMID: 37173065 DOI: 10.1016/bs.aivir.2023.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Control of plant virus diseases is a big challenge in agriculture as is resistance in plant lines to infection by viruses. Recent progress using advanced technologies has provided fast and durable alternatives. One of the most promising techniques against plant viruses that is cost-effective and environmentally safe is RNA silencing or RNA interference (RNAi), a technology that could be used alone or along with other control methods. To achieve the goals of fast and durable resistance, the expressed and target RNAs have been examined in many studies, with regard to the variability in silencing efficiency, which is regulated by various factors such as target sequences, target accessibility, RNA secondary structures, sequence variation in matching positions, and other intrinsic characteristics of various small RNAs. Developing a comprehensive and applicable toolbox for the prediction and construction of RNAi helps researchers to achieve the acceptable performance level of silencing elements. Although the attainment of complete prediction of RNAi robustness is not possible, as it also depends on the cellular genetic background and the nature of the target sequences, some important critical points have been discerned. Thus, the efficiency and robustness of RNA silencing against viruses can be improved by considering the various parameters of the target sequence and the construct design. In this review, we provide a comprehensive treatise regarding past, present and future prospective developments toward designing and applying RNAi constructs for resistance to plant viruses.
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Affiliation(s)
- Masoud Akbarimotlagh
- Plant Pathology Department, Faculty of Agriculture, Tarbiat Modares University (TMU), Tehran, Iran
| | - Abdolbaset Azizi
- Department of Plant Protection, Faculty of Agriculture, University of Kurdistan, Sanandaj, Iran.
| | - Masoud Shams-Bakhsh
- Plant Pathology Department, Faculty of Agriculture, Tarbiat Modares University (TMU), Tehran, Iran
| | - Majid Jafari
- Department of Plant Protection, Higher Education Complex of Saravan, Saravan, Iran
| | - Aysan Ghasemzadeh
- Plant Pathology Department, Faculty of Agriculture, Tarbiat Modares University (TMU), Tehran, Iran
| | - Peter Palukaitis
- Department of Horticulture Sciences, Seoul Women's University, Seoul, Republic of Korea.
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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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8
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Gouthu S, Mandelli C, Eubanks BA, Deluc LG. Transgene-free genome editing and RNAi ectopic application in fruit trees: Potential and limitations. FRONTIERS IN PLANT SCIENCE 2022; 13:979742. [PMID: 36325537 PMCID: PMC9621297 DOI: 10.3389/fpls.2022.979742] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 09/20/2022] [Indexed: 06/16/2023]
Abstract
For the past fifteen years, significant research advances in sequencing technology have led to a substantial increase in fruit tree genomic resources and databases with a massive number of OMICS datasets (transcriptomic, proteomics, metabolomics), helping to find associations between gene(s) and performance traits. Meanwhile, new technology tools have emerged for gain- and loss-of-function studies, specifically in gene silencing and developing tractable plant models for genetic transformation. Additionally, innovative and adapted transformation protocols have optimized genetic engineering in most fruit trees. The recent explosion of new gene-editing tools allows for broadening opportunities for functional studies in fruit trees. Yet, the fruit tree research community has not fully embraced these new technologies to provide large-scale genome characterizations as in cereals and other staple food crops. Instead, recent research efforts in the fruit trees appear to focus on two primary translational tools: transgene-free gene editing via Ribonucleoprotein (RNP) delivery and the ectopic application of RNA-based products in the field for crop protection. The inherent nature of the propagation system and the long juvenile phase of most fruit trees are significant justifications for the first technology. The second approach might have the public favor regarding sustainability and an eco-friendlier environment for a crop production system that could potentially replace the use of chemicals. Regardless of their potential, both technologies still depend on the foundational knowledge of gene-to-trait relationships generated from basic genetic studies. Therefore, we will discuss the status of gene silencing and DNA-based gene editing techniques for functional studies in fruit trees followed by the potential and limitations of their translational tools (RNP delivery and RNA-based products) in the context of crop production.
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Affiliation(s)
- Satyanarayana Gouthu
- Department of Horticulture, Oregon State University, Corvallis, OR, United States
| | - Christian Mandelli
- Oregon Wine Research Institute, Oregon State University, Corvallis, OR, United States
| | - Britt A. Eubanks
- Department of Horticulture, Oregon State University, Corvallis, OR, United States
| | - Laurent G. Deluc
- Department of Horticulture, Oregon State University, Corvallis, OR, United States
- Oregon Wine Research Institute, Oregon State University, Corvallis, OR, United States
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9
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Voloudakis AE, Kaldis A, Patil BL. RNA-Based Vaccination of Plants for Control of Viruses. Annu Rev Virol 2022; 9:521-548. [PMID: 36173698 DOI: 10.1146/annurev-virology-091919-073708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Plant viruses cause nearly half of the emerging plant diseases worldwide, contributing to 10-15% of crop yield losses. Control of plant viral diseases is mainly accomplished by extensive chemical applications targeting the vectors (i.e., insects, nematodes, fungi) transmitting these viruses. However, these chemicals have a significant negative effect on human health and the environment. RNA interference is an endogenous, cellular, sequence-specific RNA degradation mechanism in eukaryotes induced by double-stranded RNA molecules that has been exploited as an antiviral strategy through transgenesis. Because genetically modified crop plants are not accepted for cultivation in several countries globally, there is an urgent demand for alternative strategies. This has boosted research on exogenous application of the RNA-based biopesticides that are shown to exhibit significant protective effect against viral infections. Such environment-friendly and efficacious antiviral agents for crop protection will contribute to global food security, without adverse effects on human health.
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Affiliation(s)
- Andreas E Voloudakis
- Laboratory of Plant Breeding and Biometry, Department of Crop Science, Agricultural University of Athens, Athens, Greece;
| | - Athanasios Kaldis
- Laboratory of Plant Breeding and Biometry, Department of Crop Science, Agricultural University of Athens, Athens, Greece;
| | - Basavaprabhu L Patil
- Division of Basic Sciences, ICAR-Indian Institute of Horticultural Research, Bengaluru, Karnataka State, India
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Oberemok V, Laikova K, Golovkin I, Kryukov L, Kamenetsky-Goldstein R. Biotechnology of virus eradication and plant vaccination in phytobiome context. PLANT BIOLOGY (STUTTGART, GERMANY) 2022; 24:3-8. [PMID: 34569131 DOI: 10.1111/plb.13338] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 08/18/2021] [Indexed: 06/13/2023]
Abstract
A plant's associated biota plays an integral role in its metabolism, nutrient uptake, stress tolerance, pathogen resistance and other physiological processes. Although a virome is an integral part of the phytobiome, a major contradiction exists between the holobiont approach and the practical need to eradicate pathogens from agricultural crops. In this review, we discuss grapevine virus control, but the issue is also relevant for numerous other crops, including potato, cassava, citrus, cacao and other species. Grapevine diseases, especially viral infections, cause main crop losses. Methods have been developed to eliminate viruses and other microorganisms from plant material, but elimination of viruses from plant material does not guarantee protection from future reinfection. Elimination of viral particles in plant material could create genetic drift, leading in turn to an increase in the occurrence of pathogenic strains of viruses. A possible solution may be a combination of virus elimination and plant propagation in tissue culture with in vitro vaccination. In this context, possible strategies to control viral infections include application of plant resistance inducers, cross protection and vaccination using siRNA, dsRNA and viral replicons during plant 'cleaning' and in vitro propagation. The experience and knowledge accumulated in human immunization can help plant scientists to develop and employ new methods of protection, leading to more sustainable and healthier crop production.
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Affiliation(s)
- V Oberemok
- V.I. Vernadsky Crimean Federal University, Simferopol, Russia
- Nikita Botanical Gardens - National Scientific Centre Russian Academy of Sciences, Yalta, Russia
| | - K Laikova
- V.I. Vernadsky Crimean Federal University, Simferopol, Russia
- Research Institute of Agriculture of Crimea, Simferopol, Russia
| | - I Golovkin
- V.I. Vernadsky Crimean Federal University, Simferopol, Russia
| | - L Kryukov
- V.I. Vernadsky Crimean Federal University, Simferopol, Russia
- Lobachevsky State University of Nizhni Novgorod, Nizhni Novgorod, Russia
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Kumar KK, Varanavasiappan S, Arul L, Kokiladevi E, Sudhakar D. Strategies for Efficient RNAi-Based Gene Silencing of Viral Genes for Disease Resistance in Plants. Methods Mol Biol 2022; 2408:23-35. [PMID: 35325414 DOI: 10.1007/978-1-0716-1875-2_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
RNA interference (RNAi) is an evolutionarily conserved gene silencing mechanism in eukaryotes including fungi, plants, and animals. In plants, gene silencing regulates gene expression, provides genome stability, and protect against invading viruses. During plant virus interaction, viral genome derived siRNAs (vsiRNA) are produced to mediate gene silencing of viral genes to prevent virus multiplication. After the discovery of RNAi phenomenon in eukaryotes, it is used as a powerful tool to engineer plant viral disease resistance against both RNA and DNA viruses. Despite several successful reports on employing RNA silencing methods to engineer plant for viral disease resistance, only a few of them have reached the commercial stage owing to lack of complete protection against the intended virus. Based on the knowledge accumulated over the years on genetic engineering for viral disease resistance, there is scope for effective viral disease control through careful design of RNAi gene construct. The selection of target viral gene(s) for developing the hairpin RNAi (hp-RNAi) construct is very critical for effective protection against the viral disease. Different approaches and bioinformatics tools which can be employed for effective target selection are discussed. The selection of suitable target regions for RNAi vector construction can help to achieve a high level of transgenic virus resistance.
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Affiliation(s)
- Krish K Kumar
- Department of Plant Biotechnology, Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India.
| | - Shanmugam Varanavasiappan
- Department of Plant Biotechnology, Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India.
| | - Loganathan Arul
- Department of Plant Biotechnology, Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India
| | - Easwaran Kokiladevi
- Department of Plant Biotechnology, Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India
| | - Duraialagaraja Sudhakar
- Department of Plant Biotechnology, Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India
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Gupta D, Singh OW, Basavaraj YB, Roy A, Mukherjee SK, Mandal B. Direct Foliar Application of dsRNA Derived From the Full-Length Gene of NSs of Groundnut Bud Necrosis Virus Limits Virus Accumulation and Symptom Expression. FRONTIERS IN PLANT SCIENCE 2021; 12:734618. [PMID: 34950158 PMCID: PMC8688928 DOI: 10.3389/fpls.2021.734618] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 11/09/2021] [Indexed: 05/31/2023]
Abstract
Groundnut bud necrosis virus (GBNV) is the most significant member of the genus Orthotospovirus occurring in the Indian subcontinent. There is hardly any effective measure to prevent GBNV in crop plants. In order to develop GBNV infection prevention procedure, we examined the effect of the direct foliar application of double-stranded RNA (dsRNA) derived from the full-length NSs gene (1,320 nucleotides) of GBNV. The bacterially expressed dsRNA to the non-structural (dsNSs) gene of GBNV was purified and delivered to plants as an aqueous suspension containing 0.01% Celite for evaluating its efficacy in preventing GBNV infection in systemic host, Nicotiana benthamiana as well as in local lesion and systemic host, cowpea cv. Pusa Komal (Vigna unguiculata). The dsNSs application and challenge-inoculation were conducted in three different combinations, where plants were challenge-inoculated with GBNV a day after, immediately, and a day before the application of dsNSs. N. benthamiana plants, which were not treated with dsRNA showed severe systemic wilting and death by 9-16 days post-inoculation (dpi). The non-treated cowpea plants exhibited many chlorotic and necrotic lesions on the cotyledonary leaves followed by systemic necrosis and death of the plants by 14-16 dpi. The dsNSs treated plants in all the combinations showed significant reduction of disease severity index in both N. benthamiana and cowpea. The treatment combination where the GBNV inoculation was conducted immediately after the dsNSs treatment was found to be the most effective treatment in preventing symptom expression. The viral RNA analysis by real time PCR also showed 20 and 12.5 fold reduction of GBNV in cowpea and N. benthamiana, respectively. Our results suggest that the foliar application of dsRNA derived from the full-length NSs gene of GBNV through Celite is successful in delivering long dsRNA leading to effective prevention of GBNV infection.
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13
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Anderson AJ, Kim YC. The Plant-Stress Metabolites, Hexanoic Aacid and Melatonin, Are Potential "Vaccines" for Plant Health Promotion. THE PLANT PATHOLOGY JOURNAL 2021; 37:415-427. [PMID: 34847628 PMCID: PMC8632612 DOI: 10.5423/ppj.rw.01.2021.0011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 08/29/2021] [Accepted: 08/31/2021] [Indexed: 06/13/2023]
Abstract
A plethora of compounds stimulate protective mechanisms in plants against microbial pathogens and abiotic stresses. Some defense activators are synthetic compounds and trigger responses only in certain protective pathways, such as activation of defenses under regulation by the plant regulator, salicylic acid (SA). This review discusses the potential of naturally occurring plant metabolites as primers for defense responses in the plant. The production of the metabolites, hexanoic acid and melatonin, in plants means they are consumed when plants are eaten as foods. Both metabolites prime stronger and more rapid activation of plant defense upon subsequent stress. Because these metabolites trigger protective measures in the plant they can be considered as "vaccines" to promote plant vigor. Hexanoic acid and melatonin instigate systemic changes in plant metabolism associated with both of the major defense pathways, those regulated by SA- and jasmonic acid (JA). These two pathways are well studied because of their induction by different microbial triggers: necrosis-causing microbial pathogens induce the SA pathway whereas colonization by beneficial microbes stimulates the JA pathway. The plant's responses to the two metabolites, however, are not identical with a major difference being a characterized growth response with melatonin but not hexanoic acid. As primers for plant defense, hexanoic acid and melatonin have the potential to be successfully integrated into vaccination-like strategies to protect plants against diseases and abiotic stresses that do not involve man-made chemicals.
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Affiliation(s)
- Anne J. Anderson
- Department of Biological Engineering, Utah State University, Logan, UT 84322, USA
| | - Young Cheol Kim
- Department of Applied Biology, College of Agriculture & Life Sciences, Chonnam National University, Gwangju 61186, Korea
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14
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Holeva MC, Sklavounos A, Rajeswaran R, Pooggin MM, Voloudakis AE. Topical Application of Double-Stranded RNA Targeting 2b and CP Genes of Cucumber mosaic virus Protects Plants against Local and Systemic Viral Infection. PLANTS 2021; 10:plants10050963. [PMID: 34066062 PMCID: PMC8151262 DOI: 10.3390/plants10050963] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 03/19/2021] [Accepted: 04/08/2021] [Indexed: 02/07/2023]
Abstract
Cucumber mosaic virus (CMV) is a destructive plant virus with worldwide distribution and the broadest host range of any known plant virus, as well as a model plant virus for understanding plant–virus interactions. Since the discovery of RNA interference (RNAi) as a major antiviral defense, RNAi-based technologies have been developed for plant protection against viral diseases. In plants and animals, a key trigger of RNAi is double-stranded RNA (dsRNA) processed by Dicer and Dicer-like (DCL) family proteins in small interfering RNAs (siRNAs). In the present study, dsRNAs for coat protein (CP) and 2b genes of CMV were produced in vitro and in vivo and applied onto tobacco plants representing a systemic solanaceous host as well as on a local host plant Chenopodium quinoa. Both dsRNA treatments protected plants from local and systemic infection with CMV, but not against infection with unrelated viruses, confirming sequence specificity of antiviral RNAi. Antiviral RNAi was effective when dsRNAs were applied simultaneously with or four days prior to CMV inoculation, but not four days post inoculation. In vivo-produced dsRNAs were more effective than the in vitro-produced; in treatments with in vivo dsRNAs, dsRNA-CP was more effective than dsRNA-2b, while the effects were opposite with in vitro dsRNAs. Illumina sequencing of small RNAs from in vivo dsRNA-CP treated and non-treated tobacco plants revealed that interference with CMV infection in systemic leaves coincides with strongly reduced accumulation of virus-derived 21- and 22-nucleotide (nt) siRNAs, likely generated by tobacco DCL4 and DCL2, respectively. While the 21-nt class of viral siRNAs was predominant in non-treated plants, 21-nt and 22-nt classes accumulated at almost equal (but low) levels in dsRNA treated plants, suggesting that dsRNA treatment may boost DCL2 activity. Taken together, our findings confirm the efficacy of topical application of dsRNA for plant protection against viruses and shed more light on the mechanism of antiviral RNAi.
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Affiliation(s)
- Maria C. Holeva
- Laboratory of Bacteriology, Scientific Directorate of Phytopathology, Benaki Phytopathological Institute, 14561 Kifissia, Greece;
| | - Athanasios Sklavounos
- Laboratory of Plant Breeding and Biometry, Department of Crop Science, Agricultural University of Athens, 11855 Athens, Greece;
- Office of Rural Development and Inspections of Kephalonia, Ministry of Rural Development and Food, 28100 Argostoli, Greece
| | - Rajendran Rajeswaran
- Department of Biology, Swiss Federal Institute of Technology (ETH), Universitätsstrasse 2, 8092 Zürich, Switzerland;
| | - Mikhail M. Pooggin
- PHIM Plant Health Institute, University of Montpellier, 34980 Montpellier, France;
| | - Andreas E. Voloudakis
- Laboratory of Plant Breeding and Biometry, Department of Crop Science, Agricultural University of Athens, 11855 Athens, Greece;
- Correspondence: ; Tel.: +30-2105294213
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15
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Flores R, Navarro B, Delgado S, Serra P, Di Serio F. Viroid pathogenesis: a critical appraisal of the role of RNA silencing in triggering the initial molecular lesion. FEMS Microbiol Rev 2021; 44:386-398. [PMID: 32379313 DOI: 10.1093/femsre/fuaa011] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 05/06/2020] [Indexed: 12/15/2022] Open
Abstract
The initial molecular lesions through which viroids, satellite RNAs and viruses trigger signal cascades resulting in plant diseases are hotly debated. Since viroids are circular non-protein-coding RNAs of ∼250-430 nucleotides, they appear very convenient to address this issue. Viroids are targeted by their host RNA silencing defense, generating viroid-derived small RNAs (vd-sRNAs) that are presumed to direct Argonaute (AGO) proteins to inactivate messenger RNAs, thus initiating disease. Here, we review the existing evidence. Viroid-induced symptoms reveal a distinction. Those attributed to vd-sRNAs from potato spindle tuber viroid and members of the family Pospiviroidae (replicating in the nucleus) are late, non-specific and systemic. In contrast, those attributed to vd-sRNAs from peach latent mosaic viroid (PLMVd) and other members of the family Avsunviroidae (replicating in plastids) are early, specific and local. Remarkably, leaf sectors expressing different PLMVd-induced chloroses accumulate viroid variants with specific pathogenic determinants. Some vd-sRNAs containing such determinant guide AGO1-mediated cleavage of mRNAs that code for proteins regulating chloroplast biogenesis/development. Therefore, the initial lesions and the expected phenotypes are connected by short signal cascades, hence supporting a cause-effect relationship. Intriguingly, one virus satellite RNA initiates disease through a similar mechanism, whereas in the Pospiviroidae and in plant viruses the situation remains uncertain.
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Affiliation(s)
- Ricardo Flores
- Instituto de Biología Molecular y Celular de Plantas (CSIC-UPV), Avenida de los Naranjos s/n 46010, Valencia, Spain
| | - Beatriz Navarro
- Istituto per la Protezione Sostenibile delle Piante, Via Amendola 122/D, 70126 Bari, Italy
| | - Sonia Delgado
- Instituto de Biología Molecular y Celular de Plantas (CSIC-UPV), Avenida de los Naranjos s/n 46010, Valencia, Spain
| | - Pedro Serra
- Instituto de Biología Molecular y Celular de Plantas (CSIC-UPV), Avenida de los Naranjos s/n 46010, Valencia, Spain
| | - Francesco Di Serio
- Istituto per la Protezione Sostenibile delle Piante, Via Amendola 122/D, 70126 Bari, Italy
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16
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Kim Y, Kim YJ, Paek KH. Temperature-specific vsiRNA confers RNAi-mediated viral resistance at elevated temperature in Capsicum annuum. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:1432-1448. [PMID: 33165515 DOI: 10.1093/jxb/eraa527] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 11/02/2020] [Indexed: 05/12/2023]
Abstract
Resistance (R) gene-mediated resistance is a robust and efficient antiviral immune system in the plants. Thus, when R-mediated resistance was suppressed at elevated temperatures, resistance towards viruses was expected to be completely collapsed. Nonetheless, the multiplication of Tobacco mosaic virus pathotype P0 (TMV-P0) was inhibited, and TMV-P0 particles were only occasionally present in the systemic leaves of pepper plants (Capsicum annuum). RNAi-mediated RNA silencing is a well-known antiviral immune mechanism. At elevated temperatures, RNAi-mediated antiviral resistance was induced and virus-derived siRNAs (vsiRNAs) were dramatically increased. Through sRNA-sequencing (sRNA-Seq) analysis, we revealed that vsiRNAs derived from TMV-P0 were greatly increased. Intriguingly, virus-infected plants could select the temperature-specific vsiRNAs for antiviral resistance from the amplified vsiRNAs at elevated temperatures. Pre-application of these temperature-specific vsiRNAs endowed antiviral resistance of the plants. Therefore, plants sustain antiviral resistance by activating RNAi-mediated resistance, based on temperature-specific vsiRNAs at elevated temperatures.
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Affiliation(s)
- Yunsik Kim
- Department of Life Sciences, Korea University, Seoul, Republic of Korea
| | - Young Jin Kim
- Department of Life Sciences, Korea University, Seoul, Republic of Korea
| | - Kyung-Hee Paek
- Department of Life Sciences, Korea University, Seoul, Republic of Korea
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17
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Leonetti P, Ghasemzadeh A, Consiglio A, Gursinsky T, Behrens S, Pantaleo V. Endogenous activated small interfering RNAs in virus-infected Brassicaceae crops show a common host gene-silencing pattern affecting photosynthesis and stress response. THE NEW PHYTOLOGIST 2021; 229:1650-1664. [PMID: 32945560 PMCID: PMC7821159 DOI: 10.1111/nph.16932] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 09/04/2020] [Indexed: 05/14/2023]
Abstract
Viral infections are accompanied by a massive production of small interfering RNAs (siRNAs) of plant origin, such as virus-activated (va)siRNAs, which drive the widespread silencing of host gene expression, and whose effects in plant pathogen interactions remain unknown. By combining phenotyping and molecular analyses, we characterized vasiRNAs that are associated with typical mosaic symptoms of cauliflower mosaic virus infection in two crops, turnip (Brassica rapa) and oilseed rape (Brassica napus), and the reference plant Arabidopsis thaliana. We identified 15 loci in the three infected plant species, whose transcripts originate vasiRNAs. These loci appear to be generally affected by virus infections in Brassicaceae and encode factors that are centrally involved in photosynthesis and stress response, such as Rubisco activase (RCA), senescence-associated protein, heat shock protein HSP70, light harvesting complex, and membrane-related protein CP5. During infection, the expression of these factors is significantly downregulated, suggesting that their silencing is a central component of the plant's response to virus infections. Further findings indicate an important role for 22 nt long vasiRNAs in the plant's endogenous RNA silencing response. Our study considerably enhances knowledge about the new class of vasiRNAs that are triggered in virus-infected plants and will help to advance strategies for the engineering of gene clusters involved in the development of crop diseases.
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Affiliation(s)
- Paola Leonetti
- Department of Biology, Agricultural and Food SciencesInstitute for Sustainable Plant ProtectionBari UnitCNRBari70126Italy
| | - Aysan Ghasemzadeh
- Department of Biology, Agricultural and Food SciencesInstitute for Sustainable Plant ProtectionBari UnitCNRBari70126Italy
- Department of Plant PathologyFaculty of AgricultureTarbiat Modares UniversityTehran14115‐111Iran
- Institute of Biochemistry and Biotechnology (NFI)Section Microbial BiotechnologyMartin Luther University Halle‐WittenbergHalle/SaaleD‐06120Germany
| | - Arianna Consiglio
- Department of Biomedical SciencesInstitute for Biomedical TechnologiesBari UnitCNRBari70126Italy
| | - Torsten Gursinsky
- Institute of Biochemistry and Biotechnology (NFI)Section Microbial BiotechnologyMartin Luther University Halle‐WittenbergHalle/SaaleD‐06120Germany
| | - Sven‐Erik Behrens
- Institute of Biochemistry and Biotechnology (NFI)Section Microbial BiotechnologyMartin Luther University Halle‐WittenbergHalle/SaaleD‐06120Germany
| | - Vitantonio Pantaleo
- Department of Biology, Agricultural and Food SciencesInstitute for Sustainable Plant ProtectionBari UnitCNRBari70126Italy
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18
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Sanan-Mishra N, Abdul Kader Jailani A, Mandal B, Mukherjee SK. Secondary siRNAs in Plants: Biosynthesis, Various Functions, and Applications in Virology. FRONTIERS IN PLANT SCIENCE 2021; 12:610283. [PMID: 33737942 PMCID: PMC7960677 DOI: 10.3389/fpls.2021.610283] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 01/18/2021] [Indexed: 05/13/2023]
Abstract
The major components of RNA silencing include both transitive and systemic small RNAs, which are technically called secondary sRNAs. Double-stranded RNAs trigger systemic silencing pathways to negatively regulate gene expression. The secondary siRNAs generated as a result of transitive silencing also play a substantial role in gene silencing especially in antiviral defense. In this review, we first describe the discovery and pathways of transitivity with emphasis on RNA-dependent RNA polymerases followed by description on the short range and systemic spread of silencing. We also provide an in-depth view on the various size classes of secondary siRNAs and their different roles in RNA silencing including their categorization based on their biogenesis. The other regulatory roles of secondary siRNAs in transgene silencing, virus-induced gene silencing, transitivity, and trans-species transfer have also been detailed. The possible implications and applications of systemic silencing and the different gene silencing tools developed are also described. The details on mobility and roles of secondary siRNAs derived from viral genome in plant defense against the respective viruses are presented. This entails the description of other compatible plant-virus interactions and the corresponding small RNAs that determine recovery from disease symptoms, exclusion of viruses from shoot meristems, and natural resistance. The last section presents an overview on the usefulness of RNA silencing for management of viral infections in crop plants.
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Affiliation(s)
- Neeti Sanan-Mishra
- Plant RNAi Biology Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - A. Abdul Kader Jailani
- Plant RNAi Biology Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
- Advanced Center for Plant Virology, Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi, India
| | - Bikash Mandal
- Advanced Center for Plant Virology, Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi, India
| | - Sunil K. Mukherjee
- Advanced Center for Plant Virology, Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi, India
- *Correspondence: Sunil K. Mukherjee,
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19
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Pitzalis N, Amari K, Graindorge S, Pflieger D, Donaire L, Wassenegger M, Llave C, Heinlein M. Turnip mosaic virus in oilseed rape activates networks of sRNA-mediated interactions between viral and host genomes. Commun Biol 2020; 3:702. [PMID: 33230160 PMCID: PMC7683744 DOI: 10.1038/s42003-020-01425-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 10/22/2020] [Indexed: 11/12/2022] Open
Abstract
Virus-induced plant diseases in cultivated plants cause important damages in yield. Although the mechanisms of virus infection are intensely studied at the cell biology level, only little is known about the molecular dialog between the invading virus and the host genome. Here we describe a combinatorial genome-wide approach to identify networks of sRNAs-guided post-transcriptional regulation within local Turnip mosaic virus (TuMV) infection sites in Brassica napus leaves. We show that the induction of host-encoded, virus-activated small interfering RNAs (vasiRNAs) observed in virus-infected tissues is accompanied by site-specific cleavage events on both viral and host RNAs that recalls the activity of small RNA-induced silencing complexes (RISC). Cleavage events also involve virus-derived siRNA (vsiRNA)–directed cleavage of target host transcripts as well as cleavage of viral RNA by both host vasiRNAs and vsiRNAs. Furthermore, certain coding genes act as virus-activated regulatory hubs to produce vasiRNAs for the targeting of other host genes. The observations draw an advanced model of plant-virus interactions and provide insights into the complex regulatory networking at the plant-virus interface within cells undergoing early stages of infection. Pitzalis et al. use replicative RNAseq, small RNA (sRNA)seq, and parallel analysis of RNA ends (PARE)seq analysis to identify networks of sRNAs-guided post-transcriptional regulation within local Turnip mosaic virus infection sites. This study provides insights into the complex regulatory networking at the plantvirus interface within cells undergoing early stages of infection.
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Affiliation(s)
- Nicolas Pitzalis
- Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique (IBMP-CNRS), Université de Strasbourg, F-67000, Strasbourg, France
| | - Khalid Amari
- Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique (IBMP-CNRS), Université de Strasbourg, F-67000, Strasbourg, France.,Julius Kühn-Institute (JKI), Federal Research Centre for Cultivated Plants, Institute for Biosafety in Plant Biotechnology, Erwin-Baur-Strasse 27, 06484, Quedlinburg, Germany
| | - Stéfanie Graindorge
- Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique (IBMP-CNRS), Université de Strasbourg, F-67000, Strasbourg, France
| | - David Pflieger
- Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique (IBMP-CNRS), Université de Strasbourg, F-67000, Strasbourg, France
| | - Livia Donaire
- Department of Microbial and Plant Biotechnology, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas (CIB-CSIC), Ramiro de Maeztu 9, 28040, Madrid, Spain.,Department of Biology of Stress and Plant Pathology, Centro de Edafología y Biología Aplicada del Segura (CEBAS)-CSIC, 30100, Murcia, Spain
| | - Michael Wassenegger
- RLP Agroscience, AlPlanta-Institute for Plant Research, 67435, Neustadt, Germany.,Centre for Organismal Studies, University of Heidelberg, 69120, Heidelberg, Germany
| | - César Llave
- Department of Microbial and Plant Biotechnology, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas (CIB-CSIC), Ramiro de Maeztu 9, 28040, Madrid, Spain.
| | - Manfred Heinlein
- Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique (IBMP-CNRS), Université de Strasbourg, F-67000, Strasbourg, France.
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20
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Bennett M, Deikman J, Hendrix B, Iandolino A. Barriers to Efficient Foliar Uptake of dsRNA and Molecular Barriers to dsRNA Activity in Plant Cells. FRONTIERS IN PLANT SCIENCE 2020; 11:816. [PMID: 32595687 PMCID: PMC7304407 DOI: 10.3389/fpls.2020.00816] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 05/20/2020] [Indexed: 05/23/2023]
Abstract
Foliar application of dsRNA to elicit an RNA interference (RNAi) response is currently under consideration as a crop protection strategy. To access the RNAi machinery of a plant, foliarly applied dsRNAs must traverse the plant cuticle, avoid nuclease degradation, and penetrate the cell wall and plasma membrane. Application methods and co-formulants have been identified by Bayer Crop Science researchers and others that can help bypass barriers to dsRNA uptake in plants leading to an RNAi response in greenhouse grown, young plants and cell cultures. However, these advances in dsRNA delivery have yet to yield systemic RNAi silencing of an endogenous gene target required for product concepts such as weed control. Systemic RNAi silencing in plants has only been observed with the GFP transgene in Nicotiana benthamiana. Because biologically meaningful whole plant RNAi has not been observed for endogenous gene products in N. benthamiana or in other plant species tested, under growing conditions including field production, the regulatory risk assessment of foliarly applied dsRNA-based products should not consider exposure scenarios that include systemic response to small RNAs in treated plants.
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21
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Tenllado F, Canto T. Effects of a changing environment on the defenses of plants to viruses. Curr Opin Virol 2020; 42:40-46. [PMID: 32531746 DOI: 10.1016/j.coviro.2020.04.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 04/18/2020] [Accepted: 04/21/2020] [Indexed: 12/11/2022]
Abstract
Since their appearance, plants have lived and evolved within changing environments that were determined by a host of abiotic and biotic factors. It is in this evolutionary context that both, the mechanisms of defense by plants against viruses and the viral reprogramming of plant routes were established, which combined define the outcomes of compatible infections. Current alterations in the chemistry of the atmosphere are causing changes in the global context in which plants and viruses interact that are unprecedented not in their nature but in their pace. We discuss here the potential reach of environment changes taking place now, and how the main abiotic parameters that are driving them can affect defense responses of plants to viruses in compatible infections.
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Affiliation(s)
- Francisco Tenllado
- Department of Environmental Biology, Margarita Salas Center for Biological Research, CIB-CSIC, Ramiro de Maeztu 9, Madrid 28040, Spain
| | - Tomas Canto
- Department of Environmental Biology, Margarita Salas Center for Biological Research, CIB-CSIC, Ramiro de Maeztu 9, Madrid 28040, Spain.
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22
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Leonetti P, Miesen P, van Rij RP, Pantaleo V. Viral and subviral derived small RNAs as pathogenic determinants in plants and insects. Adv Virus Res 2020; 107:1-36. [PMID: 32711727 DOI: 10.1016/bs.aivir.2020.04.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The phenotypic manifestations of disease induced by viruses and subviral infectious entities are the result of complex molecular interactions between host and viral factors. The viral determinants of the diseased phenotype have traditionally been sought at the level of structural or non-structural proteins. However, the discovery of RNA silencing mechanisms has led to speculations that determinants of the diseased phenotype are caused by viral nucleic acid sequences in addition to proteins. RNA silencing is a gene regulation mechanism conserved within eukaryotic kingdoms (with the exception of some yeast species), and in plants and insects it also functions as an antiviral mechanism. Non-coding RNAs of viral origin, ranging in size from 21 to 24 nucleotides (viral small interfering RNAs, vsiRNAs) accumulate in virus-infected tissues and organs, in some cases to comparable levels as the entire complement of host-encoded small interfering RNAs. Upon incorporation into RNA-induced silencing complexes, vsiRNAs can mediate cleavage or induce translational inhibition of nucleic acid targets in a sequence-specific manner. This review focuses on recent findings that suggest an increased complexity of small RNA-based interactions between virus and host. We mainly address plant viruses, but where applicable discuss insect viruses as well. Prominence is given to studies that have indisputably demonstrated that vsiRNAs determine diseased phenotype by either carrying sequence determinants or, indirectly, by altering host-gene regulatory pathways. Results from these studies suggest biotechnological applications, which are also discussed.
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Affiliation(s)
- Paola Leonetti
- Department of Biology, Agricultural and Food Sciences, Institute for Sustainable Plant Protection, CNR, Bari, Italy
| | - Pascal Miesen
- Department of Medical Microbiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ronald P van Rij
- Department of Medical Microbiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.
| | - Vitantonio Pantaleo
- Department of Biology, Agricultural and Food Sciences, Institute for Sustainable Plant Protection, CNR, Bari, Italy..
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23
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Cisneros AE, Carbonell A. Artificial Small RNA-Based Silencing Tools for Antiviral Resistance in Plants. PLANTS 2020; 9:plants9060669. [PMID: 32466363 PMCID: PMC7356032 DOI: 10.3390/plants9060669] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 05/20/2020] [Accepted: 05/21/2020] [Indexed: 01/05/2023]
Abstract
Artificial small RNAs (art-sRNAs), such as artificial microRNAs (amiRNAs) and synthetic trans-acting small interfering RNAs (syn-tasiRNAs), are highly specific 21-nucleotide small RNAs designed to recognize and silence complementary target RNAs. Art-sRNAs are extensively used in gene function studies or for improving crops, particularly to protect plants against viruses. Typically, antiviral art-sRNAs are computationally designed to target one or multiple sites in viral RNAs with high specificity, and art-sRNA constructs are generated and introduced into plants that are subsequently challenged with the target virus(es). Numerous studies have reported the successful application of art-sRNAs to induce resistance against a large number of RNA and DNA viruses in model and crop species. However, the application of art-sRNAs as an antiviral tool has limitations, such as the difficulty to predict the efficacy of a particular art-sRNA or the emergence of virus variants with mutated target sites escaping to art-sRNA-mediated degradation. Here, we review the different classes, features, and uses of art-sRNA-based tools to induce antiviral resistance in plants. We also provide strategies for the rational design of antiviral art-sRNAs and discuss the latest advances in developing art-sRNA-based methodologies for enhanced resistance to plant viruses.
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24
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Affiliation(s)
- Robert J. Paxton
- Institute for Biology, Martin Luther University Halle-Wittenberg, Hoher Weg 8, 06120 Halle (Saale), Germany
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