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Kallemi P, Verret F, Andronis C, Ioannidis N, Glampedakis N, Kotzabasis K, Kalantidis K. Stress-related transcriptomic changes associated with GFP transgene expression and active transgene silencing in plants. Sci Rep 2024; 14:13314. [PMID: 38858413 PMCID: PMC11164987 DOI: 10.1038/s41598-024-63527-5] [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: 03/30/2023] [Accepted: 05/29/2024] [Indexed: 06/12/2024] Open
Abstract
Plants respond to biotic and abiotic stress by activating and interacting with multiple defense pathways, allowing for an efficient global defense response. RNA silencing is a conserved mechanism of regulation of gene expression directed by small RNAs important in acquired plant immunity and especially virus and transgene repression. Several RNA silencing pathways in plants are crucial to control developmental processes and provide protection against abiotic and biotic stresses as well as invasive nucleic acids such as viruses and transposable elements. Various notable studies have shed light on the genes, small RNAs, and mechanisms involved in plant RNA silencing. However, published research on the potential interactions between RNA silencing and other plant stress responses is limited. In the present study, we tested the hypothesis that spreading and maintenance of systemic post-transcriptional gene silencing (PTGS) of a GFP transgene are associated with transcriptional changes that pertain to non-RNA silencing-based stress responses. To this end, we analyzed the structure and function of the photosynthetic apparatus and conducted whole transcriptome analysis in a transgenic line of Nicotiana benthamiana that spontaneously initiates transgene silencing, at different stages of systemic GFP-PTGS. In vivo analysis of chlorophyll a fluorescence yield and expression levels of key photosynthetic genes indicates that photosynthetic activity remains unaffected by systemic GFP-PTGS. However, transcriptomic analysis reveals that spreading and maintenance of GFP-PTGS are associated with transcriptional reprogramming of genes that are involved in abiotic stress responses and pattern- or effector-triggered immunity-based stress responses. These findings suggest that systemic PTGS may affect non-RNA-silencing-based defense pathways in N. benthamiana, providing new insights into the complex interplay between different plant stress responses.
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Affiliation(s)
- Paraskevi Kallemi
- Department of Biology, University of Crete, 70013, Heraklion, Greece
| | - Frederic Verret
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 70013, Heraklion, Greece
| | - Christos Andronis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 70013, Heraklion, Greece
| | | | | | | | - Kriton Kalantidis
- Department of Biology, University of Crete, 70013, Heraklion, Greece.
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 70013, Heraklion, Greece.
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2
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Zhang Y, Tian X, Xu H, Zhan B, Zhou C, Li S, Zhang Z. Knockout of SlDCL2b attenuates the resistance of tomato to potato spindle tuber viroid infection. MOLECULAR PLANT PATHOLOGY 2024; 25:e13441. [PMID: 38462774 PMCID: PMC10925824 DOI: 10.1111/mpp.13441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 01/18/2024] [Accepted: 02/18/2024] [Indexed: 03/12/2024]
Abstract
RNA interference, or RNA silencing, is an important defence mechanism against viroid infection in plants. Plants encode multiple DICER-LIKE (DCL) proteins that are key components of the RNA silencing pathway. However, the roles of different DCLs in defence responses against viroid infection remain unclear. Here, we determined the function of tomato DCL2b (SlDCL2b) in defence responses against potato spindle tuber viroid (PSTVd) infection using SlDCL2b loss-of-function tomato mutant plants. Compared with wild-type plants, mutant plants were more susceptible to PSTVd infection, developing more severe symptoms earlier and accumulating higher levels of PSTVd RNAs. Moreover, we verified the feedback mechanism for the regulation of SlDCL2b expression by miR6026. Functional blocking of tomato miR6026, by expressing its target mimics, can enhance resistance to PSTVd infection in tomato plants. These findings deepen the current understanding of RNAi-based resistance against viroid infection and provide a potentially new strategy for viroid control.
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Affiliation(s)
- Yuhong Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect PestsInstitute of Plant Protection (IPP), Chinese Academy of Agricultural Sciences (CAAS)BeijingChina
| | - Xiaxia Tian
- State Key Laboratory for Biology of Plant Diseases and Insect PestsInstitute of Plant Protection (IPP), Chinese Academy of Agricultural Sciences (CAAS)BeijingChina
- Citrus Research InstituteSouthwest UniversityChongqingChina
| | - Huiyuan Xu
- State Key Laboratory for Biology of Plant Diseases and Insect PestsInstitute of Plant Protection (IPP), Chinese Academy of Agricultural Sciences (CAAS)BeijingChina
| | - Binhui Zhan
- State Key Laboratory for Biology of Plant Diseases and Insect PestsInstitute of Plant Protection (IPP), Chinese Academy of Agricultural Sciences (CAAS)BeijingChina
| | - Changyong Zhou
- Citrus Research InstituteSouthwest UniversityChongqingChina
| | - Shifang Li
- State Key Laboratory for Biology of Plant Diseases and Insect PestsInstitute of Plant Protection (IPP), Chinese Academy of Agricultural Sciences (CAAS)BeijingChina
| | - Zhixiang Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect PestsInstitute of Plant Protection (IPP), Chinese Academy of Agricultural Sciences (CAAS)BeijingChina
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3
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Singh VK, Ahmed S, Saini DK, Gahlaut V, Chauhan S, Khandare K, Kumar A, Sharma PK, Kumar J. Manipulating epigenetic diversity in crop plants: Techniques, challenges and opportunities. Biochim Biophys Acta Gen Subj 2024; 1868:130544. [PMID: 38104668 DOI: 10.1016/j.bbagen.2023.130544] [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] [Received: 09/18/2023] [Revised: 12/04/2023] [Accepted: 12/11/2023] [Indexed: 12/19/2023]
Abstract
Epigenetic modifications act as conductors of inheritable alterations in gene expression, all while keeping the DNA sequence intact, thereby playing a pivotal role in shaping plant growth and development. This review article presents an overview of techniques employed to investigate and manipulate epigenetic diversity in crop plants, focusing on both naturally occurring and artificially induced epialleles. The significance of epigenetic modifications in facilitating adaptive responses is explored through the examination of how various biotic and abiotic stresses impact them. Further, environmental chemicals are explored for their role in inducing epigenetic changes, particularly focusing on inhibitors of DNA methylation like 5-AzaC and zebularine, as well as inhibitors of histone deacetylation including trichostatin A and sodium butyrate. The review delves into various approaches for generating epialleles, including tissue culture techniques, mutagenesis, and grafting, elucidating their potential to induce heritable epigenetic modifications in plants. In addition, the ground breaking CRISPR/Cas is emphasized for its accuracy in targeting specific epigenetic changes. This presents a potent tools for deciphering the intricacies of epigenetic mechanisms. Furthermore, the intricate relationship between epigenetic modifications and non-coding RNA expression, including siRNAs and miRNAs, is investigated. The emerging role of exo-RNAi in epigenetic regulation is also introduced, unveiling its promising potential for future applications. The article concludes by addressing the opportunities and challenges presented by these techniques, emphasizing their implications for crop improvement. Conclusively, this extensive review provides valuable insights into the intricate realm of epigenetic changes, illuminating their significance in phenotypic plasticity and their potential in advancing crop improvement.
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Affiliation(s)
| | - Shoeb Ahmed
- Ch. Charan Singh University, Meerut 250004, India
| | - Dinesh Kumar Saini
- Department of Plant and Soil Science, Texas Tech University, Lubbock, TX, United States
| | - Vijay Gahlaut
- University Centre for Research and Development, Chandigarh University, Mohali 140413, Punjab, India
| | | | - Kiran Khandare
- Center of Innovative and Applied Bioprocessing, Mohali 140308, Punjab, India
| | - Ashutosh Kumar
- Center of Innovative and Applied Bioprocessing, Mohali 140308, Punjab, India
| | - Pradeep Kumar Sharma
- Ch. Charan Singh University, Meerut 250004, India; Maharaja Suhel Dev State University, Azamgarh 276404, U.P., India
| | - Jitendra Kumar
- National Agri-Food Biotechnology Institute, Sector-81, Mohali 140306, Punjab, India.
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4
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Nakashima K, Yuhazu M, Mikuriya S, Kasai M, Abe J, Taneda A, Kanazawa A. Frequency of cytosine methylation in the adjacent regions of soybean retrotransposon SORE-1 depends on chromosomal location. Genome 2024; 67:1-12. [PMID: 37746933 DOI: 10.1139/gen-2023-0044] [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: 09/26/2023]
Abstract
Mobilization of transposable elements (TEs) is suppressed by epigenetic mechanisms involving cytosine methylation. However, few studies have focused on clarifying relationships between epigenetic influences of TEs on the adjacent DNA regions and time after insertion of TEs into the genome and/or their chromosomal location. Here we addressed these issues using soybean retrotransposon SORE-1. We analyzed SORE-1, inserted in exon 1 of the GmphyA2 gene, one of the newest insertions in this family so far identified. Cytosine methylation was detected in this element but was barely present in the adjacent regions. These results were correlated, respectively, with the presence and absence of the production of short interfering RNAs. Cytosine methylation profiles of 74 SORE-1 elements in the Williams 82 reference genome indicated that methylation frequency in the adjacent regions of SORE-1 was profoundly higher in pericentromeric regions than in euchromatic chromosome arms and was only weakly correlated with the length of time after insertion into the genome. Notably, the higher level of methylation in the 5' adjacent regions of SORE-1 coincided with the presence of repetitive elements in pericentromeric regions. Together, these results suggest that epigenetic influence of SORE-1 on the adjacent regions is influenced by its location on the chromosome.
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Affiliation(s)
- Kenta Nakashima
- Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
| | - Mashiro Yuhazu
- Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
| | - Shun Mikuriya
- Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
| | - Megumi Kasai
- Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
| | - Jun Abe
- Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
| | - Akito Taneda
- Graduate School of Science and Technology, Hirosaki University, Hirosaki, Aomori 036-8561, Japan
| | - Akira Kanazawa
- Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
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5
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Ma L, Zhang X, Deng Z, Zhang P, Wang T, Li R, Li J, Cheng K, Wang J, Ma N, Qu G, Zhu B, Fu D, Luo Y, Li F, Zhu H. Dicer-like2b suppresses the wiry leaf phenotype in tomato induced by tobacco mosaic virus. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 116:1737-1747. [PMID: 37694805 DOI: 10.1111/tpj.16462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 08/28/2023] [Accepted: 09/01/2023] [Indexed: 09/12/2023]
Abstract
Dicer-like (DCL) proteins are principal components of RNA silencing, a major defense mechanism against plant virus infections. However, their functions in suppressing virus-induced disease phenotypes remain largely unknown. Here, we identified a role for tomato (Solanum lycopersicum) DCL2b in regulating the wiry leaf phenotype during defense against tobacco mosaic virus (TMV). Knocking out SlyDCL2b promoted TMV accumulation in the leaf primordium, resulting in a wiry phenotype in distal leaves. Biochemical and bioinformatics analyses showed that 22-nt virus-derived small interfering RNAs (vsiRNAs) accumulated less abundantly in slydcl2b mutants than in wild-type plants, suggesting that SlyDCL2b-dependent 22-nt vsiRNAs are required to exclude virus from leaf primordia. Moreover, the wiry leaf phenotype was accompanied by upregulation of Auxin Response Factors (ARFs), resulting from a reduction in trans-acting siRNAs targeting ARFs (tasiARFs) in TMV-infected slydcl2b mutants. Loss of tasiARF production in the slydcl2b mutant was in turn caused by inhibition of miRNA390b function. Importantly, silencing SlyARF3 and SlyARF4 largely restored the wiry phenotype in TMV-infected slydcl2b mutants. Our work exemplifies the complex relationship between RNA viruses and the endogenous RNA silencing machinery, whereby SlyDCL2b protects the normal development of newly emerging organs by excluding virus from these regions and thus maintaining developmental silencing.
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Affiliation(s)
- Liqun Ma
- The College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083, China
| | - Xi Zhang
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, China
| | - Zhiqi Deng
- The College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083, China
| | - Peiyu Zhang
- The College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083, China
| | - Tian Wang
- The College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083, China
| | - Ran Li
- The College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083, China
| | - Jinyan Li
- The College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083, China
| | - Ke Cheng
- The College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083, China
| | - Jubin Wang
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, China
| | - Nan Ma
- Department of Ornamental Horticulture, State Key Laboratory of Agrobiotechnology, Beijing Key Laboratory of Development and Quality Control of Ornamental Crops, College of Horticulture, China Agricultural University, Beijing, 100193, China
| | - Guiqin Qu
- The College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083, China
| | - Benzhong Zhu
- The College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083, China
| | - Daqi Fu
- The College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083, China
| | - Yunbo Luo
- The College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083, China
| | - Feng Li
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, China
| | - Hongliang Zhu
- The College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083, China
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6
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Pietrykowska H, Alisha A, Aggarwal B, Watanabe Y, Ohtani M, Jarmolowski A, Sierocka I, Szweykowska-Kulinska Z. Conserved and non-conserved RNA-target modules in plants: lessons for a better understanding of Marchantia development. PLANT MOLECULAR BIOLOGY 2023; 113:121-142. [PMID: 37991688 PMCID: PMC10721683 DOI: 10.1007/s11103-023-01392-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 10/19/2023] [Indexed: 11/23/2023]
Abstract
A wide variety of functional regulatory non-coding RNAs (ncRNAs) have been identified as essential regulators of plant growth and development. Depending on their category, ncRNAs are not only involved in modulating target gene expression at the transcriptional and post-transcriptional levels but also are involved in processes like RNA splicing and RNA-directed DNA methylation. To fulfill their molecular roles properly, ncRNAs must be precisely processed by multiprotein complexes. In the case of small RNAs, DICER-LIKE (DCL) proteins play critical roles in the production of mature molecules. Land plant genomes contain at least four distinct classes of DCL family proteins (DCL1-DCL4), of which DCL1, DCL3 and DCL4 are also present in the genomes of bryophytes, indicating the early divergence of these genes. The liverwort Marchantia polymorpha has become an attractive model species for investigating the evolutionary history of regulatory ncRNAs and proteins that are responsible for ncRNA biogenesis. Recent studies on Marchantia have started to uncover the similarities and differences in ncRNA production and function between the basal lineage of bryophytes and other land plants. In this review, we summarize findings on the essential role of regulatory ncRNAs in Marchantia development. We provide a comprehensive overview of conserved ncRNA-target modules among M. polymorpha, the moss Physcomitrium patens and the dicot Arabidopsis thaliana, as well as Marchantia-specific modules. Based on functional studies and data from the literature, we propose new connections between regulatory pathways involved in Marchantia's vegetative and reproductive development and emphasize the need for further functional studies to understand the molecular mechanisms that control ncRNA-directed developmental processes.
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Affiliation(s)
- Halina Pietrykowska
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Uniwersytetu Poznanskiego 6, 61-614, Poznan, Poland
| | - Alisha Alisha
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Uniwersytetu Poznanskiego 6, 61-614, Poznan, Poland
| | - Bharti Aggarwal
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Uniwersytetu Poznanskiego 6, 61-614, Poznan, Poland
| | - Yuichiro Watanabe
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, 153-8902, Japan
| | - Misato Ohtani
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, 630-0192, Nara, Japan
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, 277-8562, Chiba, Japan
- RIKEN Center for Sustainable Resource Science, Yokohama, 230-0045, Kanagawa, Japan
| | - Artur Jarmolowski
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Uniwersytetu Poznanskiego 6, 61-614, Poznan, Poland
| | - Izabela Sierocka
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Uniwersytetu Poznanskiego 6, 61-614, Poznan, Poland.
| | - Zofia Szweykowska-Kulinska
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Uniwersytetu Poznanskiego 6, 61-614, Poznan, Poland.
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7
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Kim H, Masuta C. VIGS as a strategy to reverse aphid wing induction by Y-satellite RNA of cucumber mosaic virus. FEBS Open Bio 2023; 13:2005-2019. [PMID: 37596957 PMCID: PMC10626274 DOI: 10.1002/2211-5463.13697] [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] [Received: 06/21/2023] [Revised: 08/02/2023] [Accepted: 08/17/2023] [Indexed: 08/21/2023] Open
Abstract
Y-satellite RNA (Y-sat) of cucumber mosaic virus upregulates the expression of the aphid ABCG4 gene, which promotes aphid wing formation. We used ABCG4 virus-induced gene silencing (VIGS) to prevent the wing-induction mechanism of Y-sat and thus inhibited aphid wing formation. Of the aphids on plants with VIGS of ABCG4, only about 30% had wings, and 60-70% of the winged aphids were small and likely impaired in flying ability. In addition, we showed that double-stranded RNAs (dsRNAs) and small RNAs were transferred from the plant to the aphid to adequately silence aphid genes. Supplying ABCG4 dsRNA by VIGS to aphids is thus a potential strategy to inhibit aphid wing formation.
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Affiliation(s)
- Hangil Kim
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan
| | - Chikara Masuta
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan
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8
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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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9
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Isogai M, Yoshikoshi M, Seki K, Masuko-Suzuki H, Watanabe M, Matsuo K, Yaegashi H. Seed transmission of raspberry bushy dwarf virus is blocked in Nicotiana benthamiana plants by preventing virus entry into the embryo from the infected embryo sac and endosperm. Arch Virol 2023; 168:138. [PMID: 37046148 DOI: 10.1007/s00705-023-05767-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 03/21/2023] [Indexed: 04/14/2023]
Abstract
Raspberry bushy dwarf virus (RBDV) is transmitted through seed in infected red raspberry plants after pollination with pollen grains from healthy red raspberry plants. Here, we show that RBDV is not transmitted through seeds in infected Nicotiana benthamiana (Nb) plants after pollination with virus-free Nb pollen grains. Chromogenic in situ hybridization revealed that the virus invades the shoot apical meristem and the ovule, including the embryo sac, of RBDV-infected Nb plants; however, in seeds that developed from infected embryo sacs after fertilization by virus-free sperm cells, RBDV was absent in the embryos and present in the endosperms. When we analyzed seed transmission of RBDV in Nb mutants with mutations in dicer-like enzyme 2 and 4 (NbDCL2&4) or RNA-dependent RNA polymerase 6 (NbRDR6), RBDV was not present in the offspring from seeds with embryos and endosperms that did not express NbDCL2&4 or NbRDR6. These results suggest that seed transmission of RBDV is prevented by evasion of infection by the embryo and that RNA silencing is not essential for preventing seed transmission of RBDV in Nb plants.
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Affiliation(s)
- Masamichi Isogai
- Plant Pathology Laboratory, Faculty of Agriculture, Iwate University, 18-8, Ueda 3-chome, Morioka, 020-8550, Japan.
| | - Mizuna Yoshikoshi
- Plant Pathology Laboratory, Faculty of Agriculture, Iwate University, 18-8, Ueda 3-chome, Morioka, 020-8550, Japan
| | - Kentaro Seki
- Plant Pathology Laboratory, Faculty of Agriculture, Iwate University, 18-8, Ueda 3-chome, Morioka, 020-8550, Japan
| | - Hiromi Masuko-Suzuki
- Graduate School of Life Sciences, Tohoku University, 1-1, Katahira 2-chome, Aoba-ku, Sendai, 980-8577, Japan
| | - Masao Watanabe
- Graduate School of Life Sciences, Tohoku University, 1-1, Katahira 2-chome, Aoba-ku, Sendai, 980-8577, Japan
| | - Kouki Matsuo
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, 2-17-2-1 Tsukisamu-Higashi, Toyohira-ku, Sapporo, 062-8517, Japan
| | - Hajime Yaegashi
- Plant Pathology Laboratory, Faculty of Agriculture, Iwate University, 18-8, Ueda 3-chome, Morioka, 020-8550, Japan
- Agri-Inovation Center, Iwate University, 18-8, Ueda 3-chome, 020-8550, Morioka, Japan
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10
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Ding SW. Transgene Silencing, RNA Interference, and the Antiviral Defense Mechanism Directed by Small Interfering RNAs. PHYTOPATHOLOGY 2023; 113:616-625. [PMID: 36441873 DOI: 10.1094/phyto-10-22-0358-ia] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
One important discovery in plant pathology over recent decades is the natural antiviral defense mechanism mediated by RNA interference (RNAi). In antiviral RNAi, virus infection triggers Dicer processing of virus-specific double-stranded RNA into small interfering RNAs (siRNAs). Frequently, further amplified by host enzyme and cofactors, these virus-derived siRNAs direct specific virus clearance in an Argonaute protein-containing effector complex. The siRNAs derived from viruses and viroids accumulate to very high levels during infection. Because they overlap extensively in nucleotide sequence, this allows for deep sequencing and bioinformatics assembly of total small RNAs for rapid discovery and identification of viruses and viroids. Antiviral RNAi acts as the primary defense mechanism against both RNA and DNA viruses in plants, yet viruses still successfully infect plants. They do so because all currently recognized plant viruses combat the RNAi response by encoding at least one protein as a viral suppressor of RNAi (VSR) required for infection, even though plant viruses have small genome sizes with a limited coding capacity. This review article will recapitulate the key findings that have revealed the genetic pathway for the biogenesis and antiviral activity of viral siRNAs and the specific role of VSRs in infection by antiviral RNAi suppression. Moreover, early pioneering studies on transgene silencing, RNAi, and virus-plant/virus-virus interactions paved the road to the discovery of antiviral RNAi.
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Affiliation(s)
- Shou-Wei Ding
- Department of Microbiology & Plant Pathology and Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, CA
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11
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Sehki H, Yu A, Elmayan T, Vaucheret H. TYMV and TRV infect Arabidopsis thaliana by expressing weak suppressors of RNA silencing and inducing host RNASE THREE LIKE1. PLoS Pathog 2023; 19:e1010482. [PMID: 36696453 PMCID: PMC9901757 DOI: 10.1371/journal.ppat.1010482] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 02/06/2023] [Accepted: 01/10/2023] [Indexed: 01/26/2023] Open
Abstract
Post-Transcriptional Gene Silencing (PTGS) is a defense mechanism that targets invading nucleic acids of endogenous (transposons) or exogenous (pathogens, transgenes) origins. During plant infection by viruses, virus-derived primary siRNAs target viral RNAs, resulting in both destruction of single-stranded viral RNAs (execution step) and production of secondary siRNAs (amplification step), which maximizes the plant defense. As a counter-defense, viruses express proteins referred to as Viral Suppressor of RNA silencing (VSR). Some viruses express VSRs that totally inhibit PTGS, whereas other viruses express VSRs that have limited effect. Here we show that infection with the Turnip yellow mosaic virus (TYMV) is enhanced in Arabidopsis ago1, ago2 and dcl4 mutants, which are impaired in the execution of PTGS, but not in dcl2, rdr1 and rdr6 mutants, which are impaired in the amplification of PTGS. Consistently, we show that the TYMV VSR P69 localizes in siRNA-bodies, which are the site of production of secondary siRNAs, and limits PTGS amplification. Moreover, TYMV induces the production of the host enzyme RNASE THREE-LIKE 1 (RTL1) to further reduce siRNA accumulation. Infection with the Tobacco rattle virus (TRV), which also encodes a VSR limiting PTGS amplification, induces RTL1 as well to reduce siRNA accumulation and promote infection. Together, these results suggest that RTL1 could be considered as a host susceptibility gene that is induced by viruses as a strategy to further limit the plant PTGS defense when VSRs are insufficient.
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Affiliation(s)
- Hayat Sehki
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université Paris-Saclay, Versailles, France
- Université Paris-Sud, Université Paris-Saclay, Orsay, France
| | - Agnès Yu
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université Paris-Saclay, Versailles, France
| | - Taline Elmayan
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université Paris-Saclay, Versailles, France
| | - Hervé Vaucheret
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université Paris-Saclay, Versailles, France
- * E-mail:
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12
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Dalakouras A, Katsaouni A, Avramidou M, Dadami E, Tsiouri O, Vasileiadis S, Makris A, Georgopoulou ME, Papadopoulou KK. A beneficial fungal root endophyte triggers systemic RNA silencing and DNA methylation of a host reporter gene. RNA Biol 2023; 20:20-30. [PMID: 36573793 PMCID: PMC9809956 DOI: 10.1080/15476286.2022.2159158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
A growing body of evidence suggests that RNA interference (RNAi) plays a pivotal role in the communication between plants and pathogenic fungi, where a bi-directional trans-kingdom RNAi is established to the advantage of either the host or the pathogen. Similar mechanisms acting during plant association with non-pathogenic symbiotic microorganisms have been elusive to this date. To determine whether root endophytes can induce systemic RNAi responses to their host plants, we designed an experimental reporter-based system consisting of the root-restricted, beneficial fungal endophyte, Fusarium solani strain K (FsK) and its host Nicotiana benthamiana. Since not all fungi encode the RNAi machinery, we first needed to validate that FsK does so, by identifying its core RNAi enzymes (2 Dicer-like genes, 2 Argonautes and 4 RNA-dependent RNA polymerases) and by showing its susceptibility to in vitro RNAi upon exogenous application of double stranded RNAs (dsRNAs). Upon establishing this, we transformed FsK with a hairpin RNA (hpRNA) construct designed to target a reporter gene in its host N. benthamiana. The hpRNA was processed by FsK RNAi machinery predominantly into 21-24-nt small RNAs that triggered RNA silencing but not DNA methylation in the fungal hyphae. Importantly, when the hpRNA-expressing FsK was used to inoculate N. benthamiana, systemic RNA silencing and DNA methylation of the host reporter gene was recorded. Our data suggest that RNAi signals can be translocated by root endophytes to their hosts and can modulate gene expression during mutualism, which may be translated to beneficial phenotypes.
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Affiliation(s)
- Athanasios Dalakouras
- University of Thessaly, Department of Biochemistry & Biotechnology, Larissa, Greece,Hellenic Agricultural Organization Demeter, Institute of Industrial and Forage Crops, Larissa, Greece,CONTACT Athanasios Dalakouras University of Thessaly, Department of Biochemistry & Biotechnology, Larissa, Greece; Hellenic Agricultural Organization Demeter, Institute of Industrial and Forage Crops, Larissa, Greece
| | - Afrodite Katsaouni
- University of Thessaly, Department of Biochemistry & Biotechnology, Larissa, Greece
| | - Marianna Avramidou
- University of Thessaly, Department of Biochemistry & Biotechnology, Larissa, Greece
| | - Elena Dadami
- University of Thessaly, Department of Biochemistry & Biotechnology, Larissa, Greece
| | - Olga Tsiouri
- University of Thessaly, Department of Biochemistry & Biotechnology, Larissa, Greece
| | - Sotirios Vasileiadis
- University of Thessaly, Department of Biochemistry & Biotechnology, Larissa, Greece
| | - Athanasios Makris
- University of Thessaly, Department of Biochemistry & Biotechnology, Larissa, Greece
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13
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Zand Karimi H, Innes RW. Molecular mechanisms underlying host-induced gene silencing. THE PLANT CELL 2022; 34:3183-3199. [PMID: 35666177 PMCID: PMC9421479 DOI: 10.1093/plcell/koac165] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 05/08/2022] [Indexed: 05/05/2023]
Abstract
Host-induced gene silencing (HIGS) refers to the silencing of genes in pathogens and pests by expressing homologous double-stranded RNAs (dsRNA) or artificial microRNAs (amiRNAs) in the host plant. The discovery of such trans-kingdom RNA silencing has enabled the development of RNA interference-based approaches for controlling diverse crop pathogens and pests. Although HIGS is a promising strategy, the mechanisms by which these regulatory RNAs translocate from plants to pathogens, and how they induce gene silencing in pathogens, are poorly understood. This lack of understanding has led to large variability in the efficacy of various HIGS treatments. This variability is likely due to multiple factors, such as the ability of the target pathogen or pest to take up and/or process RNA from the host, the specific genes and target sequences selected in the pathogen or pest for silencing, and where, when, and how the dsRNAs or amiRNAs are produced and translocated. In this review, we summarize what is currently known about the molecular mechanisms underlying HIGS, identify key unanswered questions, and explore strategies for improving the efficacy and reproducibility of HIGS treatments in the control of crop diseases.
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Affiliation(s)
- Hana Zand Karimi
- Department of Biology, Indiana University, Bloomington, Indiana 47405, USA
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14
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Nucleotide mismatches prevent intrinsic self-silencing of hpRNA transgenes to enhance RNAi stability in plants. Nat Commun 2022; 13:3926. [PMID: 35798725 PMCID: PMC9263138 DOI: 10.1038/s41467-022-31641-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Accepted: 06/27/2022] [Indexed: 11/10/2022] Open
Abstract
Hairpin RNA (hpRNA) transgenes are the most successful RNA interference (RNAi) method in plants. Here, we show that hpRNA transgenes are invariably methylated in the inverted-repeat (IR) DNA and the adjacent promoter, causing transcriptional self-silencing. Nucleotide substitutions in the sense sequence, disrupting the IR structure, prevent the intrinsic DNA methylation resulting in more uniform and persistent RNAi. Substituting all cytosine with thymine nucleotides, in a G:U hpRNA design, prevents self-silencing but still allows for the formation of hpRNA due to G:U wobble base-pairing. The G:U design induces effective RNAi in 90–96% of transgenic lines, compared to 57–65% for the traditional hpRNA design. While a traditional hpRNA transgene shows increasing self-silencing from cotyledons to true leaves, its G:U counterpart avoids this and induce RNAi throughout plant growth. Furthermore, siRNAs from G:U and traditional hpRNA show different characteristics and appear to function via different pathways to induce target DNA methylation. Long hairpin RNA (hpRNA) transgenes are the most widely used RNAi technology in plants, but are potentially subject to self-induced transcriptional silencing. Here, the authors show nucleotide mismatches prevent intrinsic self-silencing of hpRNA transgenes in Arabidopsis and tobacco.
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15
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Fletcher SJ, Peters JR, Olaya C, Persley DM, Dietzgen RG, Carroll BJ, Pappu H, Mitter N. Tospoviruses Induce Small Interfering RNAs Targeting Viral Sequences and Endogenous Transcripts in Solanaceous Plants. Pathogens 2022; 11:pathogens11070745. [PMID: 35889991 PMCID: PMC9317859 DOI: 10.3390/pathogens11070745] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 06/22/2022] [Accepted: 06/28/2022] [Indexed: 02/01/2023] Open
Abstract
Tospoviruses infect numerous crop species worldwide, causing significant losses throughout the supply chain. As a defence mechanism, plants use RNA interference (RNAi) to generate virus-derived small-interfering RNAs (vsiRNAs), which target viral transcripts for degradation. Small RNA sequencing and in silico analysis of capsicum and N. benthamiana infected by tomato spotted wilt virus (TSWV) or capsicum chlorosis virus (CaCV) demonstrated the presence of abundant vsiRNAs, with host-specific differences evident for each pathosystem. Despite the biogenesis of vsiRNAs in capsicum and N. benthamiana, TSWV and CaCV viral loads were readily detectable. In response to tospovirus infection, the solanaceous host species also generated highly abundant virus-activated small interfering RNAs (vasiRNAs) against many endogenous transcripts, except for an N. benthamiana accession lacking a functional RDR1 gene. Strong enrichment for ribosomal protein-encoding genes and for many genes involved in protein processing in the endoplasmic reticulum suggested co-localisation of viral and endogenous transcripts as a basis for initiating vasiRNA biogenesis. RNA-seq and RT-qPCR-based analyses of target transcript expression revealed an inconsistent role for vasiRNAs in modulating gene expression in N. benthamiana, which may be characteristic of this tospovirus-host pathosystem.
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Affiliation(s)
- Stephen J. Fletcher
- Centre for Horticultural Science, Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia; (S.J.F.); (J.R.P.); (R.G.D.)
| | - Jonathan R. Peters
- Centre for Horticultural Science, Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia; (S.J.F.); (J.R.P.); (R.G.D.)
| | - Cristian Olaya
- Department of Plant Pathology, Washington State University, Pullman, WA 99164-6430, USA;
| | - Denis M. Persley
- Queensland Department of Agriculture and Fisheries, AgriScience Queensland, EcoSciences Precinct, Dutton Park, Brisbane, QLD 4102, Australia;
| | - Ralf G. Dietzgen
- Centre for Horticultural Science, Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia; (S.J.F.); (J.R.P.); (R.G.D.)
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia;
| | - Bernard J. Carroll
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia;
| | - Hanu Pappu
- Department of Plant Pathology, Washington State University, Pullman, WA 99164-6430, USA;
- Correspondence: (H.P.); (N.M.)
| | - Neena Mitter
- Centre for Horticultural Science, Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia; (S.J.F.); (J.R.P.); (R.G.D.)
- Correspondence: (H.P.); (N.M.)
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16
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Liu S, Chen M, Li R, Li WX, Gal-On A, Jia Z, Ding SW. Identification of positive and negative regulators of antiviral RNA interference in Arabidopsis thaliana. Nat Commun 2022; 13:2994. [PMID: 35637208 PMCID: PMC9151786 DOI: 10.1038/s41467-022-30771-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 05/18/2022] [Indexed: 02/06/2023] Open
Abstract
Virus-host coevolution often drives virus immune escape. However, it remains unknown whether natural variations of plant virus resistance are enriched in genes of RNA interference (RNAi) pathway known to confer essential antiviral defense in plants. Here, we report two genome-wide association study screens to interrogate natural variation among wild-collected Arabidopsis thaliana accessions in quantitative resistance to the endemic cucumber mosaic virus (CMV). We demonstrate that the highest-ranked gene significantly associated with resistance from both screens acts to regulate antiviral RNAi in ecotype Columbia-0. One gene, corresponding to Reduced Dormancy 5 (RDO5), enhances resistance by promoting amplification of the virus-derived small interfering RNAs (vsiRNAs). Interestingly, the second gene, designated Antiviral RNAi Regulator 1 (VIR1), dampens antiviral RNAi so its genetic inactivation by CRISPR/Cas9 editing enhances both vsiRNA production and CMV resistance. Our findings identify positive and negative regulators of the antiviral RNAi defense that may play important roles in virus-host coevolution.
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Affiliation(s)
- Si Liu
- Department of Microbiology & Plant Pathology, University of California, Riverside, CA, USA
| | - Meijuan Chen
- Department of Microbiology & Plant Pathology, University of California, Riverside, CA, USA
| | - Ruidong Li
- Department of Botany & Plant Sciences, University of California, Riverside, CA, USA
| | - Wan-Xiang Li
- Department of Microbiology & Plant Pathology, University of California, Riverside, CA, USA
| | - Amit Gal-On
- Department of Plant Pathology and Weed Science, Volcani Center, Rishon LeZion, 7528809, Israel
| | - Zhenyu Jia
- Department of Botany & Plant Sciences, University of California, Riverside, CA, USA.
| | - Shou-Wei Ding
- Department of Microbiology & Plant Pathology, University of California, Riverside, CA, USA.
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17
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Malhotra EV, Jain R, Tyagi S, Raman KV, Bansal S, Aminedi R, Pattanayak D. Comparative analysis of herbivory responsive miRNAs to delineate pod borer (Helicoverpa armigera) resistance mechanisms in Cajanus cajan and its wild relative Cajanus scarabaeoides. PLANT CELL REPORTS 2022; 41:1147-1161. [PMID: 35366099 DOI: 10.1007/s00299-022-02842-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 02/04/2022] [Indexed: 06/14/2023]
Abstract
Comparative analysis of herbivory responsive miRNAs between pod borer susceptible C. cajan and its resistant Crop Wild Relative (CWR) C. scarabaeoides revealed miRNA-based regulation of defense genes and plant-insect interactions. Gram pod borer (Helicoverpa armigera) is one of most devastating pests of pigeon pea (Cajanus cajan) worldwide, responsible for huge losses in crop productivity. The lack of genes conferring resistance to pod borer in pigeon pea has proven to be a bottleneck for its improvement. One of its CWR, C. scarabaeoides has demonstrated resistance to this pest and can be exploited for developing pest resistant crop varieties. Differences in expression patterns of herbivory responsive microRNAs in the susceptible C. cajan and resistant C. scarabaeoides after different time duration of pod borer infestation (2 h, 8 h and 18 h) were identified, characterized and functionally validated to understand their role in insect defense response. A total of 462 conserved and 449 novel miRNAs and 273 conserved and 185 novel miRNAs, were identified in C. cajan and C. scarabaeoides, respectively. Among the identified miRNAs, 65, 68 and 65 miRNAs were found to be differentially expressing between the C. scarabaeoides and C. cajan libraries 2 h, 8 h and 18 h post infestation, respectively. These miRNAs were found to target genes involved in a number of pathways contributing to defense and acquired resistance in C. scarabaeoides against pod borer, indicating miRNA-based regulation of defense pathways. Expression patterns of eight of these miRNAs were validated by qRT-PCR. This study provides novel insights into the miRNA-mediated plant-insect interactions and the mechanisms of regulatory pathways involved in insect defense. These findings can be utilized for further exploring the mechanism of herbivore defense in plant systems.
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Affiliation(s)
| | - Rishu Jain
- ICAR-National Bureau of Plant Genetic Resources, New Delhi, India
| | - Saurabh Tyagi
- ICAR-National Institute for Plant Biotechnology, New Delhi, India
| | - K Venkat Raman
- ICAR-National Institute for Plant Biotechnology, New Delhi, India
| | - Sangita Bansal
- ICAR-National Bureau of Plant Genetic Resources, New Delhi, India
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18
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Uslu VV, Dalakouras A, Steffens VA, Krczal G, Wassenegger M. High-pressure sprayed siRNAs influence the efficiency but not the profile of transitive silencing. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 109:1199-1212. [PMID: 34882879 DOI: 10.1111/tpj.15625] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 11/18/2021] [Accepted: 11/26/2021] [Indexed: 06/13/2023]
Abstract
In plants, small interfering RNAs (siRNAs) are a quintessential class of RNA interference (RNAi)-inducing molecules produced by the endonucleolytic cleavage of double-stranded RNAs (dsRNAs). In order to ensure robust RNAi, siRNAs are amplified through a positive feedback mechanism called transitivity. Transitivity relies on RNA-DIRECTED RNA POLYMERASE 6 (RDR6)-mediated dsRNA synthesis using siRNA-targeted RNA. The newly synthesized dsRNA is subsequently cleaved into secondary siRNAs by DICER-LIKE (DCL) endonucleases. Just like primary siRNAs, secondary siRNAs are also loaded into ARGONAUTE proteins (AGOs) to form an RNA-induced silencing complex reinforcing the cleavage of the target RNA. Although the molecular players underlying transitivity are well established, the mode of action of transitivity remains elusive. In this study, we investigated the influence of primary target sites on transgene silencing and transitivity using the green fluorescent protein (GFP)-expressing Nicotiana benthamiana 16C line, high-pressure spraying protocol, and synthetic 22-nucleotide (nt) long siRNAs. We found that the 22-nt siRNA targeting the 3' of the GFP transgene was less efficient in inducing silencing when compared with the siRNAs targeting the 5' and middle region of the GFP. Moreover, sRNA sequencing of locally silenced leaves showed that the amount but not the profile of secondary RNAs is shaped by the occupancy of the primary siRNA triggers on the target RNA. Our findings suggest that RDR6-mediated dsRNA synthesis is not primed by primary siRNAs and that dsRNA synthesis appears to be generally initiated at the 3'-end of the target RNA.
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Affiliation(s)
- Veli Vural Uslu
- AlPlanta-Institute for Plant Research, RLP AgroScience GmbH, Neustadt an der Weinstraße, Germany
| | - Athanasios Dalakouras
- Institute of Industrial and Forage Crops, Hellenic Agricultural Organization ELGO-DEMETER, Larissa, Greece
| | - Victor A Steffens
- AlPlanta-Institute for Plant Research, RLP AgroScience GmbH, Neustadt an der Weinstraße, Germany
| | - Gabi Krczal
- AlPlanta-Institute for Plant Research, RLP AgroScience GmbH, Neustadt an der Weinstraße, Germany
| | - Michael Wassenegger
- AlPlanta-Institute for Plant Research, RLP AgroScience GmbH, Neustadt an der Weinstraße, Germany
- Centre for Organismal Studies Heidelberg, University of Heidelberg, Heidelberg, Germany
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19
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Liu H, Shen E, Wu H, Ma W, Chen H, Lin Y. Trans-kingdom expression of an insect endogenous microRNA in rice enhances resistance to striped stem borer Chilo suppressalis. PEST MANAGEMENT SCIENCE 2022; 78:770-777. [PMID: 34704657 DOI: 10.1002/ps.6690] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 10/27/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND The striped stem borer (SSB), Chilo suppressalis Walker, is a major pest of rice worldwide. Breeding of transgenic rice expressing Bacillus thuringiensis (Bt) toxins is a powerful strategy to control SSB. However, pests may evolve certain resistance to Bt toxins in transgenic plants. Hence, new controlling strategies must be continuously developed. RESULTS We successfully generated SSB-resistant rice (csu-53) expressing the artificial microRNA (amiRNA) of SSB endogenous miRNA (csu-novel-miR53) through the RNAi-based technology. Feeding assays demonstrated that csu-53 rice inhibited larval growth, delayed pupation time, and reduced pupal weight and eclosion rate of SSB larva. In a 10-day feeding experiment, the miRNA mimic of csu-novel-miR53 also suppressed larval growth and more importantly increased larval mortality. Transcriptome analysis identified 28 differentially expressed unigenes (DEGs) in the midgut between SSB larvae fed on csu-53 rice and the wild type. One DEG (DN90065_c0_g12) validated by qRT-PCR had a predicted target site of csu-novel-miR53. In addition, in vitro double-stranded RNA synthesis and further feeding assay proved that DN90065_c0_g12 is most likely the target of csu-novel-miR53. CONCLUSION amiRNA-mediated strategy can be applied to the development of insect-resistant crops, and the novel amiRNA csu-novel-miR53 of SSB has important application potential in developing SSB resistant rice. © 2021 Society of Chemical Industry.
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Affiliation(s)
- Haoju Liu
- National Key Laboratory of Crop Genetic Improvement, National Centre of Plant Gene Research, Wuhan, China
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Enlong Shen
- National Key Laboratory of Crop Genetic Improvement, National Centre of Plant Gene Research, Wuhan, China
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Hao Wu
- National Key Laboratory of Crop Genetic Improvement, National Centre of Plant Gene Research, Wuhan, China
- Henry Fok School of Biology and Agriculture, Shaoguan University, Shaoguan, China
| | - Weihua Ma
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Hao Chen
- National Key Laboratory of Crop Genetic Improvement, National Centre of Plant Gene Research, Wuhan, China
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Yongjun Lin
- National Key Laboratory of Crop Genetic Improvement, National Centre of Plant Gene Research, Wuhan, China
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
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20
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Coordinated Action of RTBV and RTSV Proteins Suppress Host RNA Silencing Machinery. Microorganisms 2022; 10:microorganisms10020197. [PMID: 35208652 PMCID: PMC8875415 DOI: 10.3390/microorganisms10020197] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 12/30/2021] [Accepted: 01/05/2022] [Indexed: 11/17/2022] Open
Abstract
RNA silencing is as an adaptive immune response in plants that limits the accumulation or spread of invading viruses. Successful virus infection entails countering the RNA silencing machinery for efficient replication and systemic spread in the host. The viruses encode proteins with the ability to suppress or block the host silencing mechanism, resulting in severe pathogenic symptoms and diseases. Tungro is a viral disease caused by a complex of two viruses and it provides an excellent system to understand the host and virus interactions during infection. It is known that Rice tungro bacilliform virus (RTBV) is the major determinant of the disease while Rice tungro spherical virus (RTSV) accentuates the symptoms. This study brings to focus the important role of RTBV ORF-IV in disease manifestation, by acting as both the victim and silencer of the RNA silencing pathway. The ORF-IV is a weak suppressor of the S-PTGS or stable silencing, but its suppression activity is augmented in the presence of specific RTSV proteins. Among these, RTBV ORF-IV and RTSV CP3 proteins interact with each other. This interaction may lead to the suppression of localized silencing as well as the spread of silencing in the host plants. The findings present a probable mechanistic glimpse of the requirement of the two viruses in enhancing tungro disease.
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21
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Jiao Y, Zhao X, Hao K, Gao X, Xing D, Wang Z, An M, Xia Z, Wu Y. Characterization of small interfering RNAs derived from pepper mild mottle virus in infected pepper plants by high-throughput sequencing. Virus Res 2022; 307:198607. [PMID: 34688783 DOI: 10.1016/j.virusres.2021.198607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 10/12/2021] [Accepted: 10/17/2021] [Indexed: 11/25/2022]
Abstract
Pepper mild mottle virus (PMMoV) infects pepper plants and induces severe yield losses in China. However, the molecular interaction between PMMoV and pepper plants is largely unknown. RNA silencing is a eukaryotically conserved mechanism against viruses mediated by virus-derived small interfering RNAs (vsiRNAs) in plants. In this study, the profiles of vsiRNAs from PMMoV in infected pepper plants were obtained by high-throughput sequencing. The results showed that vsiRNAs were predominantly 21 and 22 nucleotides (nts) in length, and had a U bias at the 5'-terminal. The single-nucleotide resolution maps revealed that vsiRNAs were heterogeneously distributed throughout PMMoV genomic RNAs and hotspots of sense and antisense strands were mainly located in the RdRp and CP coding regions. The host transcripts targeted by vsiRNAs were predicted and they are mainly involved in physiological pathways related to stress response, cell regulation, and metabolism process. In addition, PMMoV infection induced significant up-regulation of CaAGO1a/1b/2, CaDCL2 and CaRDR1 gene transcripts in pepper plants, which are important components involved in antiviral RNA silencing pathway. Taken together, our results suggest the possible roles of vsiRNAs in PMMoV-pepper interactions.
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Affiliation(s)
- Yubing Jiao
- Liaoning Key Laboratory of Plant Pathology, College of Plant Protection, Shenyang Agricultural University, Shenyang 110866, China; Key Laboratory of Tobacco Pest Monitoring Controlling & Integrated Management, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao 266101, China
| | - Xiuxiang Zhao
- Liaoning Key Laboratory of Plant Pathology, College of Plant Protection, Shenyang Agricultural University, Shenyang 110866, China
| | - Kaiqiang Hao
- Liaoning Key Laboratory of Plant Pathology, College of Plant Protection, Shenyang Agricultural University, Shenyang 110866, China
| | - Xinran Gao
- Liaoning Key Laboratory of Plant Pathology, College of Plant Protection, Shenyang Agricultural University, Shenyang 110866, China
| | - Dan Xing
- Institute of Pepper, Guizhou Academy of Agricultural Sciences, Guiyang 550006, China
| | - Zhiping Wang
- Liaoning Key Laboratory of Plant Pathology, College of Plant Protection, Shenyang Agricultural University, Shenyang 110866, China
| | - Mengnan An
- Liaoning Key Laboratory of Plant Pathology, College of Plant Protection, Shenyang Agricultural University, Shenyang 110866, China
| | - Zihao Xia
- Liaoning Key Laboratory of Plant Pathology, College of Plant Protection, Shenyang Agricultural University, Shenyang 110866, China.
| | - Yuanhua Wu
- Liaoning Key Laboratory of Plant Pathology, College of Plant Protection, Shenyang Agricultural University, Shenyang 110866, China.
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22
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Pantaleo V, Masuta C. Diversity of viral RNA silencing suppressors and their involvement in virus-specific symptoms. Adv Virus Res 2022; 113:1-23. [DOI: 10.1016/bs.aivir.2022.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Nili O, Azizi A, Abdollahzadeh J. Development of an efficient Tef-1α RNA hairpin structure to efficient management of Lasiodiplodia theobromae and Neofusicoccum parvum. Sci Rep 2021; 11:9612. [PMID: 33953257 PMCID: PMC8099910 DOI: 10.1038/s41598-021-88422-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 04/12/2021] [Indexed: 12/05/2022] Open
Abstract
Lasiodiplodia theobromae and Neofusicoccum parvum are serious worldwide-distributed plant pathogenic fungi with a wide host range in tropical and temperate climates. They cause fruit rot, canker, and dieback of twigs in various woody plants. Protection of pruning wounds using fungicides is the prevalent strategy for the management of the diseases caused by these fungi. Chemical control of plant diseases is not environmentally safe and the residues of fungicides are a threat to nature. Furthermore, genetic resources of resistance to plant diseases in woody plants are limited. The aim of this study was to investigate the efficiency of RNA silencing using an efficient hairpin structure based on Tef-1α gene for the management of L. theobromae and N. parvum. Hairpin structure of Tef-1α was cloned in pFGC5941 binary vector and the recombinant construct was named pFGC-TEF-d. Transient expression of pFGC-TEF-d using Agrobacterium LBA4404 in grapevine (Bidaneh Sefid cv.) and strawberry cultivars (Camarosa and Ventana) led to a reduction in disease progress of L. theobromae. The disease reduction in grapevine was estimated by 55% and in strawberries cultivars Camarosa and Ventana by 58% and 93%, respectively. Further analysis of transient expression of pFGC-TEF-d in strawberry (Camarosa) shown disease reduction using Neofusicoccum parvum. Here we introduce RNAi silencing using pFGC-TEF-d construct as an efficient strategy to the management of L. theobromae and N. parvum for the first time.
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Affiliation(s)
- Omid Nili
- Department of Plant Protection, University of Kurdistan, 66177-15175, Sanandaj, Iran
| | - Abdolbaset Azizi
- Department of Plant Protection, University of Kurdistan, 66177-15175, Sanandaj, Iran.
| | - Jafar Abdollahzadeh
- Department of Plant Protection, University of Kurdistan, 66177-15175, Sanandaj, Iran.
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Del Mar Martínez-Prada M, Curtin SJ, Gutiérrez-González JJ. Potato improvement through genetic engineering. GM CROPS & FOOD 2021; 12:479-496. [PMID: 34991415 PMCID: PMC9208627 DOI: 10.1080/21645698.2021.1993688] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Potato (Solanum tuberosum L.) is the third most important crop worldwide and a staple food for many people worldwide. Genetically, it poses many challenges for traditional breeding due to its autotetraploid nature and its tendency toward inbreeding depression. Breeding programs have focused on productivity, nutritional quality, and disease resistance. Some of these traits exist in wild potato relatives but their introgression into elite cultivars can take many years and, for traits such as pest resistance, their effect is often short-lasting. These problems can be addressed by genetic modification (GM) or gene editing (GE) and open a wide horizon for potato crop improvement. Current genetically modified and gene edited varieties include those with Colorado potato beetle and late blight resistance, reduction in acrylamide, and modified starch content. RNAi hairpin technology can be used to silence the haplo-alleles of multiple genes simultaneously, whereas optimization of newer gene editing technologies such as base and prime editing will facilitate the routine generation of advanced edits across the genome. These technologies will likely gain further relevance as increased target specificity and decreased off-target effects are demonstrated. In this Review, we discuss recent work related to these technologies in potato improvement.
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Affiliation(s)
- María Del Mar Martínez-Prada
- Departamento De Biología Molecular, Facultad De Ciencias Biológicas Y Ambientales, Universidad De León, León, España
| | - Shaun J Curtin
- United States Department of Agriculture, Plant Science Research Unit, Minnesota, USA.,Department of Agronomy and Plant Genetics, University of Minnesota, Minnesota, USA.,Center for Plant Precision Genomics, University of Minnesota, Minneapolis, Minnesota, USA.,Center for Genome Engineering, University of Minnesota, Minneapolis, Minnesota, USA
| | - Juan J Gutiérrez-González
- Departamento De Biología Molecular, Facultad De Ciencias Biológicas Y Ambientales, Universidad De León, León, España
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Uslu VV, Bassler A, Krczal G, Wassenegger M. High-Pressure-Sprayed Double Stranded RNA Does Not Induce RNA Interference of a Reporter Gene. FRONTIERS IN PLANT SCIENCE 2020; 11:534391. [PMID: 33391294 PMCID: PMC7773025 DOI: 10.3389/fpls.2020.534391] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 11/18/2020] [Indexed: 05/10/2023]
Abstract
In plants, RNA interference (RNAi) is an effective defense mechanism against pathogens and pests. RNAi mainly involves the micro RNA and the small interfering RNA (siRNA) pathways. The latter pathway is generally based on the processing of long double stranded RNAs (dsRNA) into siRNAs by DICER-LIKE endonucleases (DCLs). SiRNAs are loaded onto ARGONAUTE proteins to constitute the RNA-induced silencing complex (RISC). Natural dsRNAs derive from transcription of inverted repeats or of specific RNA molecules that are transcribed by RNA-directed RNA polymerase 6 (RDR6). Moreover, replication of infecting viruses/viroids results in the production of dsRNA intermediates that can serve as substrates for DCLs. The high effectiveness of RNAi both locally and systemically implicated that plants could become resistant to pathogens, including viruses, through artificial activation of RNAi by topical exogenous application of dsRNA. The most preferable procedure to exploit RNAi would be to simply spray naked dsRNAs onto mature plants that are specific for the attacking pathogens serving as a substitute for pesticides applications. However, the plant cell wall is a difficult barrier to overcome and only few reports claim that topical application of naked dsRNA triggers RNAi in plants. Using a transgenic Nicotiana benthamiana line, we found that high-pressure-sprayed naked dsRNA did not induce silencing of a green fluorescence protein (GFP) reporter gene. Small RNA sequencing (sRNA-seq) of the samples from dsRNA sprayed leaves revealed that the dsRNA was, if at all, not efficiently processed into siRNAs indicating that the dsRNA was insufficiently taken up by plant cells.
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Affiliation(s)
- Veli Vural Uslu
- AlPlanta-Institute for Plant Research, RLP AgroScience GmbH, Neustadt an der Weinstraße, Germany
| | - Alexandra Bassler
- AlPlanta-Institute for Plant Research, RLP AgroScience GmbH, Neustadt an der Weinstraße, Germany
| | - Gabi Krczal
- AlPlanta-Institute for Plant Research, RLP AgroScience GmbH, Neustadt an der Weinstraße, Germany
| | - Michael Wassenegger
- AlPlanta-Institute for Plant Research, RLP AgroScience GmbH, Neustadt an der Weinstraße, Germany
- Centre for Organismal Studies Heidelberg, Heidelberg University, Heidelberg, Germany
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Li N, Yu C, Yin Y, Gao S, Wang F, Jiao C, Yao M. Pepper Crop Improvement Against Cucumber Mosaic Virus (CMV): A Review. FRONTIERS IN PLANT SCIENCE 2020; 11:598798. [PMID: 33362830 PMCID: PMC7758397 DOI: 10.3389/fpls.2020.598798] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 11/13/2020] [Indexed: 06/12/2023]
Abstract
Cucumber mosaic virus (CMV) is a prevalent virus affecting the quality and yield of pepper, resulting in yield losses of greater than 80% during severe local epidemics. Cultural practices and the heavy use of agrochemicals are the most common control measures for CMV. Sources of resistance provide a practical reference and a basis for breeding for CMV resistance. Genetic factors underlying CMV resistance have been studied and advanced breeding lines and cultivars with improved resistance have been developed by traditional breeding methods. Additionally, QTLs or genes for CMV resistance have been identified and can be utilized for marker-assisted resistance breeding. This review focuses on status and prospect of CMV against different virus strains, host resistance, and its applied genetics. With the advent of novel technologies, more useful markers and precise approaches can facilitate the progress for improving CMV resistance in Capsicum.
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Affiliation(s)
| | | | | | | | | | - Chunhai Jiao
- Hubei Key Laboratory of Vegetable Germplasm Innovation and Genetic Improvement, Cash Crops Research Institute, Hubei Academy of Agricultural Sciences, Wuhan, China
| | - Minghua Yao
- Hubei Key Laboratory of Vegetable Germplasm Innovation and Genetic Improvement, Cash Crops Research Institute, Hubei Academy of Agricultural Sciences, Wuhan, China
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Marwal A, Gaur RK. Host Plant Strategies to Combat Against Viruses Effector Proteins. Curr Genomics 2020; 21:401-410. [PMID: 33093803 PMCID: PMC7536791 DOI: 10.2174/1389202921999200712135131] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 06/17/2020] [Accepted: 06/19/2020] [Indexed: 02/02/2023] Open
Abstract
Viruses are obligate parasites that exist in an inactive state until they enter the host body. Upon entry, viruses become active and start replicating by using the host cell machinery. All plant viruses can augment their transmission, thus powering their detrimental effects on the host plant. To diminish infection and diseases caused by viruses, the plant has a defence mechanism known as pathogenesis-related biochemicals, which are metabolites and proteins. Proteins that ultimately prevent pathogenic diseases are called R proteins. Several plant R genes (that confirm resistance) and avirulence protein (Avr) (pathogen Avr gene-encoded proteins [effector/elicitor proteins involved in pathogenicity]) molecules have been identified. The recognition of such a factor results in the plant defence mechanism. During plant viral infection, the replication and expression of a viral molecule lead to a series of a hypersensitive response (HR) and affect the host plant's immunity (pathogen-associated molecular pattern-triggered immunity and effector-triggered immunity). Avr protein renders the host RNA silencing mechanism and its innate immunity, chiefly known as silencing suppressors towards the plant defensive machinery. This is a strong reply to the plant defensive machinery by harmful plant viruses. In this review, we describe the plant pathogen resistance protein and how these proteins regulate host immunity during plant-virus interactions. Furthermore, we have discussed regarding ribosome-inactivating proteins, ubiquitin proteasome system, translation repression (nuclear shuttle protein interacting kinase 1), DNA methylation, dominant resistance genes, and autophagy-mediated protein degradation, which are crucial in antiviral defences.
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Affiliation(s)
- Avinash Marwal
- 1Department of Biotechnology, Vigyan Bhawan - Block B, New Campus, Mohanlal Sukhadia University, Udaipur, Rajasthan - 313001, India; 2Department of Biotechnology, Deen Dayal Upadhyay Gorakhpur University, Gorakhpur, Uttar Pradesh - 273009, India
| | - Rajarshi Kumar Gaur
- 1Department of Biotechnology, Vigyan Bhawan - Block B, New Campus, Mohanlal Sukhadia University, Udaipur, Rajasthan - 313001, India; 2Department of Biotechnology, Deen Dayal Upadhyay Gorakhpur University, Gorakhpur, Uttar Pradesh - 273009, India
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Shen C, Wei C, Li J, Zhang X, Zhong Q, Li Y, Bai B, Wu Y. Barley yellow dwarf virus-GAV-derived vsiRNAs are involved in the production of wheat leaf yellowing symptoms by targeting chlorophyll synthase. Virol J 2020; 17:158. [PMID: 33087133 PMCID: PMC7576850 DOI: 10.1186/s12985-020-01434-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 10/12/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Wheat yellow dwarf virus disease is infected by barley yellow dwarf virus (BYDV), which causes leaf yellowing and dwarfing symptoms in wheat, thereby posing a serious threat to China's food production. The infection of plant viruses can produce large numbers of vsiRNAs, which can target host transcripts and cause symptom development. However, few studies have been conducted to explore the role played by vsiRNAs in the interaction between BYDV-GAV and host wheat plants. METHODS In this study, small RNA sequencing was conducted to profile vsiRNAs in BYDV-GAV-infected wheat plants. The putative targets of vsiRNAs were predicted by the bioinformatics software psRNATarget. RT-qPCR and VIGS were employed to identify the function of selected target transcripts. To confirm the interaction between vsiRNA and the target, 5' RACE was performed to analyze the specific cleavage sites. RESULTS From the sequencing data, we obtained a total of 11,384 detected vsiRNAs. The length distribution of these vsiRNAs was mostly 21 and 22 nt, and an A/U bias was observed at the 5' terminus. We also observed that the production region of vsiRNAs had no strand polarity. The vsiRNAs were predicted to target 23,719 wheat transcripts. GO and KEGG enrichment analysis demonstrated that these targets were mostly involved in cell components, catalytic activity and plant-pathogen interactions. The results of RT-qPCR analysis showed that most chloroplast-related genes were downregulated in BYDV-GAV-infected wheat plants. Silencing of a chlorophyll synthase gene caused leaf yellowing that was similar to the symptoms exhibited by BYDV-GAV-inoculated wheat plants. A vsiRNA from an overlapping region of BYDV-GAV MP and CP was observed to target chlorophyll synthase for gene silencing. Next, 5' RACE validated that vsiRNA8856 could cleave the chlorophyll synthase transcript in a sequence-specific manner. CONCLUSIONS This report is the first to demonstrate that BYDV-GAV-derived vsiRNAs can target wheat transcripts for symptom development, and the results of this study help to elucidate the molecular mechanisms underlying leaf yellowing after viral infection.
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Affiliation(s)
- Chuan Shen
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, 712100, China
| | - Caiyan Wei
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, 712100, China
| | - Jingyuan Li
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, 712100, China
| | - Xudong Zhang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, 712100, China
| | - Qinrong Zhong
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, 712100, China
| | - Yue Li
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, 712100, China
| | - Bixin Bai
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, 712100, China
| | - Yunfeng Wu
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, 712100, China.
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Orr RG, Foley SJ, Sherman C, Abreu I, Galotto G, Liu B, González-Guerrero M, Vidali L. Robust Survival-Based RNA Interference of Gene Families Using in Tandem Silencing of Adenine Phosphoribosyltransferase. PLANT PHYSIOLOGY 2020; 184:607-619. [PMID: 32764132 PMCID: PMC7536682 DOI: 10.1104/pp.20.00865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 07/15/2020] [Indexed: 05/07/2023]
Abstract
RNA interference (RNAi) enables flexible and dynamic interrogation of entire gene families or essential genes without the need for exogenous proteins, unlike CRISPR-Cas technology. Unfortunately, isolation of plants undergoing potent gene silencing requires laborious design, visual screening, and physical separation for downstream characterization. Here, we developed an adenine phosphoribosyltransferase (APT)-based RNAi technology (APTi) in Physcomitrella patens that improves upon the multiple limitations of current RNAi techniques. APTi exploits the prosurvival output of transiently silencing APT in the presence of 2-fluoroadenine, thereby establishing survival itself as a reporter of RNAi. To maximize the silencing efficacy of gene targets, we created vectors that facilitate insertion of any gene target sequence in tandem with the APT silencing motif. We tested the efficacy of APTi with two gene families, the actin-dependent motor, myosin XI (a,b), and the putative chitin receptor Lyk5 (a,b,c). The APTi approach resulted in a homogenous population of transient P. patens mutants specific for our gene targets with zero surviving background plants within 8 d. The observed mutants directly corresponded to a maximal 93% reduction of myosin XI protein and complete loss of chitin-induced calcium spiking in the Lyk5-RNAi background. The positive selection nature of APTi represents a fundamental improvement in RNAi technology and will contribute to the growing demand for technologies amenable to high-throughput phenotyping.
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Affiliation(s)
- Robert G Orr
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, Massachusetts 01609
| | - Stephen J Foley
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, Worcester, Massachusetts 01609
| | - Catherine Sherman
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, Massachusetts 01609
- Bioinformatics and Computational Biology Program, Worcester Polytechnic Institute, Worcester, Massachusetts 01605
| | - Isidro Abreu
- Centro de Biotecnología y Genómica de Plantas (UPM-INIA), Universidad Politécnica de Madrid, Madrid 28223, Spain
| | - Giulia Galotto
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, Massachusetts 01609
| | - Boyuan Liu
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, Massachusetts 01609
| | - Manuel González-Guerrero
- Centro de Biotecnología y Genómica de Plantas (UPM-INIA), Universidad Politécnica de Madrid, Madrid 28223, Spain
| | - Luis Vidali
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, Massachusetts 01609
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, Worcester, Massachusetts 01609
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30
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Rolling Circle Amplification (RCA)-Mediated Genome-Wide ihpRNAi Mutant Library Construction in Brassica napus. Int J Mol Sci 2020; 21:ijms21197243. [PMID: 33008068 PMCID: PMC7582411 DOI: 10.3390/ijms21197243] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 09/25/2020] [Accepted: 09/28/2020] [Indexed: 12/15/2022] Open
Abstract
With the successful completion of genomic sequencing for Brassica napus, identification of novel genes, determination of functions performed by genes, and exploring the molecular mechanisms underlying important agronomic traits were challenged. Mutagenesis-based functional genomics techniques including chemical, physical, and insertional mutagenesis have been used successfully in the functional characterization of genes. However, these techniques had their disadvantages and inherent limitations for allopolyploid Brassica napus, which contained a large number of homologous and redundant genes. Long intron-spliced hairpin RNA (ihpRNA) constructs which contained inverted repeats of the target gene separated by an intron, had been shown to be very effective in triggering RNAi in plants. In the present study, the genome-wide long ihpRNA library of B. napus was constructed with the rolling circle amplification (RCA)-mediated technology. Using the phytoene desaturase (PDS) gene as a target control, it was shown that the RCA-mediated long ihpRNA construct was significantly effective in triggering gene silence in B. napus. Subsequently, the resultant long ihpRNA library was transformed into B. napus to produce corresponding RNAi mutants. Among the obtained transgenic ihpRNA population of B. napus, five ihpRNA lines with observable mutant phenotypes were acquired including alterations in the floral model and the stamen development. The target genes could be quickly identified using specific primers. These results showed that the RCA-mediated ihpRNA construction method was effective for the genome-wide long ihpRNA library of B. napus, therefore providing a platform for study of functional genomics in allopolyploid B. napus.
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Bally J, Fishilevich E, Doran RL, Lee K, de Campos SB, German MA, Narva KE, Waterhouse PM. Plin-amiR, a pre-microRNA-based technology for controlling herbivorous insect pests. PLANT BIOTECHNOLOGY JOURNAL 2020; 18:1925-1932. [PMID: 32012433 PMCID: PMC7415779 DOI: 10.1111/pbi.13352] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 01/16/2020] [Accepted: 01/20/2020] [Indexed: 05/21/2023]
Abstract
The cotton bollworm, Helicoverpa armigera, is a major insect pest for a wide range of agricultural crops. It causes significant yield loss through feeding damage and by increasing the crop's vulnerability to bacterial and fungal infections. Although expression of Bacillus thuringiensis (Bt) toxins in transgenic crops has been very successful in protecting against insect pests, including H. armigera, field-evolved resistance has occurred in multiple species. To manage resistant populations, new protection strategies must be continuously developed. Trans-kingdom RNA interference (TK-RNAi) is a promising method for controlling herbivorous pests. TK-RNAi is based on delivering dsRNA or hairpin RNA containing essential insect gene sequences to the feeding insect. The ingested molecules are processed by the insect's RNAi machinery and guide it to silence the target genes. Recently, TK-RNAi delivery has been enhanced by expressing the ds- or hpRNAs in the chloroplast. This compartmentalizes the duplexed RNA away from the plant's RNAi machinery, ensuring that it is delivered in an unprocessed form to the insect. Here, we report another alternative approach for delivering precursor anti-insect RNA in plants. Insect pre-microRNA (pre-miR) transcripts were modified to contain artificial microRNAs (amiRs), targeting insect genes, and expressed in transgenic Nicotiana benthamiana plants. These modified pre-miRs remained largely unprocessed in the plants, and H. armigera feeding on leaves from these plants had increased mortality, developmental abnormalities and delayed growth rates. This shows that plant-expressed insect pre-amiRs (plin-amiRs) are a new strategy of protecting plants against herbivorous insects.
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Affiliation(s)
- Julia Bally
- Centre for Tropical Crops and BiocommoditiesQUTBrisbaneQLDAustralia
| | - Elane Fishilevich
- Agriculture Division of DowDuPont™Corteva Agriscience™IndianapolisINUSA
- Department of EntomologyUniversity of Nebraska‐LincolnLincolnNEUSA
| | - Rachel L. Doran
- Centre for Tropical Crops and BiocommoditiesQUTBrisbaneQLDAustralia
| | - Karen Lee
- Centre for Tropical Crops and BiocommoditiesQUTBrisbaneQLDAustralia
| | | | - Marcelo A. German
- Agriculture Division of DowDuPont™Corteva Agriscience™IndianapolisINUSA
| | - Kenneth E. Narva
- Agriculture Division of DowDuPont™Corteva Agriscience™IndianapolisINUSA
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F de Felippes F, McHale M, Doran RL, Roden S, Eamens AL, Finnegan EJ, Waterhouse PM. The key role of terminators on the expression and post-transcriptional gene silencing of transgenes. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 104:96-112. [PMID: 32603508 DOI: 10.1111/tpj.14907] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 05/08/2020] [Accepted: 06/17/2020] [Indexed: 05/18/2023]
Abstract
Transgenes have become essential to modern biology, being an important tool in functional genomic studies and also in the development of biotechnological products. One of the major challenges in the generation of transgenic lines concerns the expression of transgenes, which, compared to endogenes, are particularly susceptible to silencing mediated by small RNAs (sRNAs). Several reasons have been put forward to explain why transgenes often trigger the production of sRNAs, such as the high level of expression induced by commonly used strong constitutive promoters, the lack of introns, and features resembling viral and other exogenous sequences. However, the relative contributions of the different genomic elements with respect to protecting genes from the silencing machinery and their molecular mechanisms remain unclear. Here, we present the results of a mutagenesis screen conceived to identify features involved in the protection of endogenes against becoming a template for the production of sRNAs. Interestingly, all of the recovered mutants had alterations in genes with proposed function in transcription termination, suggesting a central role of terminators in this process. Indeed, using a GFP reporter system, we show that, among different genetic elements tested, the terminator sequence had the greatest effect on transgene-derived sRNA accumulation and that a well-defined poly(A) site might be especially important. Finally, we describe an unexpected mechanism, where transgenes containing certain intron/terminator combinations lead to an increase in the production of sRNAs, which appears to interfere with splicing.
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Affiliation(s)
- Felipe F de Felippes
- Centre for Agriculture and the Bioeconomy, Institute for Future Environments, Queensland University of Technology (QUT), 2 George Street, Brisbane, QLD, 4000, Australia
| | - Marcus McHale
- Plant Systems Biology Laboratory, Áras de Brún, National University of Ireland Galway (NUIG), Research Road, Galway, H91TK33, Ireland
| | - Rachel L Doran
- Centre for Agriculture and the Bioeconomy, Institute for Future Environments, Queensland University of Technology (QUT), 2 George Street, Brisbane, QLD, 4000, Australia
| | - Sally Roden
- Centre for Agriculture and the Bioeconomy, Institute for Future Environments, Queensland University of Technology (QUT), 2 George Street, Brisbane, QLD, 4000, Australia
| | - Andrew L Eamens
- School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW, 2308, Australia
| | - E Jean Finnegan
- CSIRO Agriculture and Food, GPO Box 1700, Canberra, ACT, 2601, Australia
| | - Peter M Waterhouse
- Centre for Agriculture and the Bioeconomy, Institute for Future Environments, Queensland University of Technology (QUT), 2 George Street, Brisbane, QLD, 4000, Australia
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33
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Dalakouras A, Papadopoulou KK. Epigenetic Modifications: An Unexplored Facet of Exogenous RNA Application in Plants. PLANTS 2020; 9:plants9060673. [PMID: 32466487 PMCID: PMC7356522 DOI: 10.3390/plants9060673] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 05/22/2020] [Accepted: 05/23/2020] [Indexed: 01/09/2023]
Abstract
Exogenous RNA interference (exo-RNAi) is a powerful transgene-free tool in modern crop improvement and protection platforms. In exo-RNAi approaches, double-stranded RNAs (dsRNAs) or short-interfering RNAs (siRNAs) are externally applied in plants in order to selectively trigger degradation of target mRNAs. Yet, the applied dsRNAs may also trigger unintended epigenetic alterations and result in epigenetically modified plants, an issue that has not been sufficiently addressed and which merits more careful consideration.
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Affiliation(s)
- Athanasios Dalakouras
- Department of Biochemistry & Biotechnology, University of Thessaly, 41500 Larissa, Greece;
- Institute of Plant Breeding and Genetic Resources ELGO-DEMETER, 57001 Thessaloniki, Greece
- Correspondence:
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The Tomato spotted wilt virus (TSWV) Genome is Differentially Targeted in TSWV-Infected Tomato ( Solanum lycopersicum) with or without Sw-5 Gene. Viruses 2020; 12:v12040363. [PMID: 32224858 PMCID: PMC7232525 DOI: 10.3390/v12040363] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 03/16/2020] [Accepted: 03/17/2020] [Indexed: 12/11/2022] Open
Abstract
Tospoviruses cause significant losses to a wide range of agronomic and horticultural crops worldwide. The type member, Tomato spotted wilt tospovirus (TSWV), causes systemic infection in susceptible tomato cultivars, whereas its infection is localized in cultivars carrying the Sw-5 resistance gene. The response to TSWV infection in tomato cultivars with or without Sw-5 was determined at the virus small RNA level in the locally infected leaf. Predicted reads were aligned to TSWV reference sequences. The TSWV genome was found to be differentially processed among each of the three-viral genomic RNAs—Large (L), Medium (M) and Small (S)—in the Sw-5(+) compared to Sw-5(−) genotypes. In the Sw-5(+) cultivar, the L RNA had the highest number of viral small-interfering RNAs (vsiRNAs), whereas in the Sw-5(−) cultivar the number was higher in the S RNA. Among the three-viral genomic RNAs, the distribution of hotspots showed a higher number of reads per million reads of vsiRNAs of 21 and 22 nt class at the 5′ and 3′ ends of the L and the S RNAs, with less coverage in the M RNA. In the Sw-5(−) cultivar, the nature of the 5′ nucleotide-end in the siRNAs varied significantly; reads with 5′-adenine-end were most abundant in the mock control, whereas cytosine and uracil were more abundant in the infected plants. No such differences were seen in case of the resistant genotype. Findings provided insights into the response of tomato cultivars to TSWV infection.
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Hudzik C, Hou Y, Ma W, Axtell MJ. Exchange of Small Regulatory RNAs between Plants and Their Pests. PLANT PHYSIOLOGY 2020; 182:51-62. [PMID: 31636103 PMCID: PMC6945882 DOI: 10.1104/pp.19.00931] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 10/02/2019] [Indexed: 05/09/2023]
Abstract
Regulatory small RNAs are well known as antiviral agents, regulators of gene expression, and defenders of genome integrity in plants. Several studies over the last decade have also shown that some small RNAs are exchanged between plants and their pathogens and parasites. Naturally occurring trans-species small RNAs are used by host plants to silence mRNAs in pathogens. These gene-silencing events are thought to be detrimental to the pathogen and beneficial to the host. Conversely, trans-species small RNAs from pathogens and parasites are deployed to silence host mRNAs; these events are thought to be beneficial for the pests. The natural ability of plants to exchange small RNAs with invading eukaryotic organisms can be exploited to provide disease resistance. This review gives an overview of the current state of trans-species small RNA research in plants and discusses several outstanding questions for future research.
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Affiliation(s)
- Collin Hudzik
- Department of Biology, Intercollege Ph.D. Program in Plant Biology, and Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania 16802
| | - Yingnan Hou
- Department of Microbiology and Plant Pathology, Center for Plant Cell Biology, University of California, Riverside, California 92521
| | - Wenbo Ma
- Department of Microbiology and Plant Pathology, Center for Plant Cell Biology, University of California, Riverside, California 92521
| | - Michael J Axtell
- Department of Biology, Intercollege Ph.D. Program in Plant Biology, and Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania 16802
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de Felippes FF, Waterhouse PM. The Whys and Wherefores of Transitivity in Plants. FRONTIERS IN PLANT SCIENCE 2020; 11:579376. [PMID: 32983223 PMCID: PMC7488869 DOI: 10.3389/fpls.2020.579376] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 08/14/2020] [Indexed: 05/05/2023]
Abstract
Transitivity in plants is a mechanism that produces secondary small interfering RNAs (siRNAs) from a transcript targeted by primary small RNAs (sRNAs). It expands the silencing signal to additional sequences of the transcript. The process requires RNA-dependent RNA polymerases (RDRs), which convert single-stranded RNA targets into a double-stranded (ds) RNA, the precursor of siRNAs and is critical for effective and amplified responses to virus infection. It is also important for the production of endogenous secondary siRNAs, such as phased siRNAs (phasiRNAs), which regulate several genes involved in development and adaptation. Transitivity on endogenous transcripts is very specific, utilizing special primary sRNAs, such as miRNAs with unique features, and particular ARGONAUTEs. In contrast, transitivity on transgene and virus (exogenous) transcripts is more generic. This dichotomy of responses implies the existence of a mechanism that differentiates self from non-self targets. In this work, we examine the possible mechanistic process behind the dichotomy and the intriguing counter-intuitive directionality of transitive sequence-spread in plants.
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Abstract
Protection against microbial infection in eukaryotes is provided by diverse cellular and molecular mechanisms. Here, we present a comparative view of the antiviral activity of virus-derived small interfering RNAs in fungi, plants, invertebrates and mammals, detailing the mechanisms for their production, amplification and activity. We also highlight the recent discovery of viral PIWI-interacting RNAs in animals and a new role for mobile host and pathogen small RNAs in plant defence against eukaryotic pathogens. In turn, viruses that infect plants, insects and mammals, as well as eukaryotic pathogens of plants, have evolved specific virulence proteins that suppress RNA interference (RNAi). Together, these advances suggest that an antimicrobial function of the RNAi pathway is conserved across eukaryotic kingdoms.
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Moura MO, Fausto AKS, Fanelli A, Guedes FADF, Silva TDF, Romanel E, Vaslin MFS. Genome-wide identification of the Dicer-like family in cotton and analysis of the DCL expression modulation in response to biotic stress in two contrasting commercial cultivars. BMC PLANT BIOLOGY 2019; 19:503. [PMID: 31729948 PMCID: PMC6858778 DOI: 10.1186/s12870-019-2112-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 10/31/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND Dicer-like proteins (DCLs) are essential players in RNA-silencing mechanisms, acting in gene regulation via miRNAs and in antiviral protection in plants and have also been associated to other biotic and abiotic stresses. To the best of our knowledge, despite being identified in some crops, cotton DCLs haven't been characterized until now. In this work, we characterized the DCLs of three cotton species and analyzed their expression profiles during biotic stress. RESULTS As main results, 11 DCLs in the allotetraploid cotton Gossypium hirsutum, 7 and 6 in the diploid G. arboreum and G. raimondii, were identified, respectively. Among some DCLs duplications observed in these genomes, the presence of an extra DCL3 in the three cotton species were detected, which haven't been found in others eudicots. All the DCL types identified by in silico analysis in the allotetraploid cotton genome were able to generate transcripts, as observed by gene expression analysis in distinct tissues. Based on the importance of DCLs for plant defense against virus, responses of cotton DCLs to virus infection and/or herbivore attack using two commercial cotton cultivars (cv.), one susceptible (FM966) and another resistant (DO) to polerovirus CLRDV infection, were analyzed. Both cvs. Responded differently to virus infection. At the inoculation site, the resistant cv. showed strong induction of DCL2a and b, while the susceptible cv. showed a down-regulation of these genes, wherever DCL4 expression was highly induced. A time course of DCL expression in aerial parts far from inoculation site along infection showed that DCL2b and DCL4 were repressed 24 h after infection in the susceptible cotton. As CLRDV is aphid-transmitted, herbivore attack was also checked. Opposite expression pattern of DCL2a and b and DCL4 was observed for R and S cottons, showing that aphid feeding alone may induce DCL modulation. CONCLUSIONS Almost all the DCLs of the allotetraploide G. hirsutum cotton were found in their relative diploids. Duplications of DCL2 and DCL3 were found in the three species. All four classes of DCL responded to aphid attack and virus infection in G. hirsutum. DCLs initial responses against the virus itself and/or herbivore attack may be contributing towards virus resistance.
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Affiliation(s)
- Marianna O. Moura
- Departamento de Virologia, Instituto de Microbiologia, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ 21941-590 Brazil
| | - Anna Karoline S. Fausto
- Departamento de Virologia, Instituto de Microbiologia, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ 21941-590 Brazil
| | - Amanda Fanelli
- Departamento de Biotecnologia, Escola de Engenharia de Lorena/Universidade de São Paulo (EEL/USP), Lorena, SP 12602-810 Brazil
| | - Fernanda A. de F. Guedes
- Programa de Pós-graduação em Biotecnologia Vegetal, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ 21941-590 Brazil
| | - Tatiane da F. Silva
- Departamento de Biotecnologia, Escola de Engenharia de Lorena/Universidade de São Paulo (EEL/USP), Lorena, SP 12602-810 Brazil
| | - Elisson Romanel
- Departamento de Biotecnologia, Escola de Engenharia de Lorena/Universidade de São Paulo (EEL/USP), Lorena, SP 12602-810 Brazil
| | - Maite F. S. Vaslin
- Departamento de Virologia, Instituto de Microbiologia, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ 21941-590 Brazil
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Kakiyama S, Tabara M, Nishibori Y, Moriyama H, Fukuhara T. Long DCL4-substrate dsRNAs efficiently induce RNA interference in plant cells. Sci Rep 2019; 9:6920. [PMID: 31061468 PMCID: PMC6502814 DOI: 10.1038/s41598-019-43443-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 02/26/2019] [Indexed: 12/29/2022] Open
Abstract
RNA interference (RNAi) is induced by the direct transfer of double-stranded RNAs (dsRNAs) into protoplasts prepared from Arabidopsis thaliana seedlings. In this protoplast RNAi system, we compared the efficacies of various-sized dsRNAs (between 21 and 139 nucleotides [nt]) for inducing RNAi and assessed the dsRNA-cleaving activities of Dicer-like 3 (DCL3) and 4 (DCL4). After the direct transfer of dsRNAs into protoplasts, cleaved RNA products of 21 nt were detected from long 130- or 500-nt dsRNAs by DCL4 but not from 37-nt dsRNAs. These results indicate that DCL4 preferentially cleaves long dsRNAs in protoplasts, consistent with our previous biochemical data regarding the substrate specificity of DCL4. Direct transfer of long dsRNAs of approximately 130 nt into protoplasts induces RNAi much more effectively (by approximately 60- to 400-fold) than direct transfer of short 37-nt dsRNAs. Although transfer of 21-nt dsRNAs into protoplasts induced RNAi without DCL4 activity, the induction of RNAi was less effective (by approximately 0.01-fold) compared with long dsRNAs. These results indicate that cleavage of long dsRNAs exceeding 100 nt by DCL4 into 21-nt dsRNAs is essential for efficient induction of RNAi in plant cells.
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Affiliation(s)
- Sayaka Kakiyama
- Department of Applied Biological Sciences, Tokyo University of Agriculture and Technology, 3-5-8 Saiwaicho, Fuchu, Tokyo, 183-8509, Japan
| | - Midori Tabara
- Department of Applied Biological Sciences, Tokyo University of Agriculture and Technology, 3-5-8 Saiwaicho, Fuchu, Tokyo, 183-8509, Japan
| | - Yuki Nishibori
- Department of Applied Biological Sciences, Tokyo University of Agriculture and Technology, 3-5-8 Saiwaicho, Fuchu, Tokyo, 183-8509, Japan
| | - Hiromitsu Moriyama
- Department of Applied Biological Sciences, Tokyo University of Agriculture and Technology, 3-5-8 Saiwaicho, Fuchu, Tokyo, 183-8509, Japan
| | - Toshiyuki Fukuhara
- Department of Applied Biological Sciences, Tokyo University of Agriculture and Technology, 3-5-8 Saiwaicho, Fuchu, Tokyo, 183-8509, Japan. .,Institute of Global Innovation Research, Tokyo University of Agriculture and Technology, 3-5-8 Saiwaicho, Fuchu, Tokyo, 183-8509, Japan.
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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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Dalakouras A, Lauter A, Bassler A, Krczal G, Wassenegger M. Transient expression of intron-containing transgenes generates non-spliced aberrant pre-mRNAs that are processed into siRNAs. PLANTA 2019; 249:457-468. [PMID: 30251012 DOI: 10.1007/s00425-018-3015-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 09/20/2018] [Indexed: 05/10/2023]
Abstract
MAIN CONCLUSION In this study, we show that aberrant pre-mRNAs from non-spliced and non-polyadenylated intron-containing transgenes are channelled to the RNA silencing pathway. In plants, improperly processed transcripts are called aberrant RNAs (ab-RNAs) and are eliminated by either RNA silencing or RNA decay mechanisms. Ab-RNAs transcribed from intronless genes are copied by RNA-directed RNA polymerases (RDRs) into double-stranded RNAs which are subsequently cleaved by DICER-LIKE endonucleases into small RNAs (sRNAs). In contrast, ab-RNAs from intron-containing genes are suggested to be channelled post-splicing to exonucleolytic degradation. Yet, it is not clear how non-spliced aberrant pre-mRNAs are eliminated. We reasoned that transient expression of agroinfiltrated intron-containing transgenes in Nicotiana benthamiana would allow us to study the steady-state levels of non-spliced pre-mRNAs. SRNA deep sequencing of the agroinfiltrated transgenes revealed the presence of sRNAs mapping to the entire non-spliced pre-mRNA suggesting that RDRs (most likely RDR6) processed aberrant non-spliced pre-mRNAs. Primary and secondary sRNAs with lengths of 18-25 nucleotides (nt) were detected, with the most prominent sRNA size class of 22 nt. SRNAs also mapped to the terminator sequence, indicating that RDR substrates also comprised read-through transcripts devoid of polyadenylation tail. Importantly, the occurring sRNAs efficiently targeted cognate mRNA for degradation but failed to cleave the non-spliced pre-mRNA, corroborating the notion that sRNAs are not triggering RNA cleavage in the nucleus.
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Affiliation(s)
- Athanasios Dalakouras
- RLP AgroScience GmbH, AlPlanta-Institute for Plant Research, 67435, Neustadt, Germany.
- Institute of Plant Breeding and Genetic Resources ELGO-DEMETER, 57001, Thessaloniki, Greece.
| | - Anja Lauter
- RLP AgroScience GmbH, AlPlanta-Institute for Plant Research, 67435, Neustadt, Germany
| | - Alexandra Bassler
- RLP AgroScience GmbH, AlPlanta-Institute for Plant Research, 67435, Neustadt, Germany
| | - Gabi Krczal
- RLP AgroScience GmbH, AlPlanta-Institute for Plant Research, 67435, Neustadt, Germany
| | - Michael Wassenegger
- RLP AgroScience GmbH, AlPlanta-Institute for Plant Research, 67435, Neustadt, Germany.
- Centre for Organismal Studies (COS) Heidelberg, University of Heidelberg, 69120, Heidelberg, Germany.
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RNA Interference: A Natural Immune System of Plants to Counteract Biotic Stressors. Cells 2019; 8:cells8010038. [PMID: 30634662 PMCID: PMC6356646 DOI: 10.3390/cells8010038] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 01/01/2019] [Accepted: 01/07/2019] [Indexed: 02/06/2023] Open
Abstract
During plant-pathogen interactions, plants have to defend the living transposable elements from pathogens. In response to such elements, plants activate a variety of defense mechanisms to counteract the aggressiveness of biotic stressors. RNA interference (RNAi) is a key biological process in plants to inhibit gene expression both transcriptionally and post-transcriptionally, using three different groups of proteins to resist the virulence of pathogens. However, pathogens trigger an anti-silencing mechanism through the expression of suppressors to block host RNAi. The disruption of the silencing mechanism is a virulence strategy of pathogens to promote infection in the invaded hosts. In this review, we summarize the RNA silencing pathway, anti-silencing suppressors, and counter-defenses of plants to viral, fungal, and bacterial pathogens.
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Arif M, Islam SU, Adnan M, Anwar M, Ali H, Wu Z. Recent progress on gene silencing/suppression by virus-derived small interfering RNAs in rice viruses especially Rice grassy stunt virus. Microb Pathog 2018; 125:210-218. [DOI: 10.1016/j.micpath.2018.09.021] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 09/08/2018] [Accepted: 09/11/2018] [Indexed: 12/16/2022]
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Pooggin MM. Small RNA-Omics for Plant Virus Identification, Virome Reconstruction, and Antiviral Defense Characterization. Front Microbiol 2018; 9:2779. [PMID: 30524398 PMCID: PMC6256188 DOI: 10.3389/fmicb.2018.02779] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 10/30/2018] [Indexed: 11/13/2022] Open
Abstract
RNA interference (RNAi)-based antiviral defense generates small interfering RNAs that represent the entire genome sequences of both RNA and DNA viruses as well as viroids and viral satellites. Therefore, deep sequencing and bioinformatics analysis of small RNA population (small RNA-ome) allows not only for universal virus detection and genome reconstruction but also for complete virome reconstruction in mixed infections. Viral infections (like other stress factors) can also perturb the RNAi and gene silencing pathways regulating endogenous gene expression and repressing transposons and host genome-integrated endogenous viral elements which can potentially be released from the genome and contribute to disease. This review describes the application of small RNA-omics for virus detection, virome reconstruction and antiviral defense characterization in cultivated and non-cultivated plants. Reviewing available evidence from a large and ever growing number of studies of naturally or experimentally infected hosts revealed that all families of land plant viruses, their satellites and viroids spawn characteristic small RNAs which can be assembled into contigs of sufficient length for virus, satellite or viroid identification and for exhaustive reconstruction of complex viromes. Moreover, the small RNA size, polarity and hotspot profiles reflect virome interactions with the plant RNAi machinery and allow to distinguish between silent endogenous viral elements and their replicating episomal counterparts. Models for the biogenesis and functions of small interfering RNAs derived from all types of RNA and DNA viruses, satellites and viroids as well as endogenous viral elements are presented and discussed.
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Affiliation(s)
- Mikhail M. Pooggin
- Institut National de la Recherche Agronomique, UMR BGPI, Montpellier, France
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45
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Lee CH, Carroll BJ. Evolution and Diversification of Small RNA Pathways in Flowering Plants. PLANT & CELL PHYSIOLOGY 2018; 59:2169-2187. [PMID: 30169685 DOI: 10.1093/pcp/pcy167] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 08/30/2018] [Indexed: 06/08/2023]
Abstract
Small regulatory RNAs guide gene silencing at the DNA or RNA level through repression of complementary sequences. The two main forms of small RNAs are microRNA (miRNA) and small interfering RNA (siRNAs), which are generated from the processing of different forms of double-stranded RNA (dsRNA) precursors. These two forms of small regulatory RNAs function in distinct but overlapping gene silencing pathways in plants. Gene silencing pathways in eukaryotes evolved from an ancient prokaryotic mechanism involved in genome defense against invasive genetic elements, but has since diversified to also play a crucial role in regulation of endogenous gene expression. Here, we review the biogenesis of the different forms of small RNAs in plants, including miRNAs, phased, secondary siRNAs (phasiRNAs) and heterochromatic siRNAs (hetsiRNAs), with a focus on their functions in genome defense, transcriptional and post-transcriptional gene silencing, RNA-directed DNA methylation, trans-chromosomal methylation and paramutation. We also discuss the important role that gene duplication has played in the functional diversification of gene silencing pathways in plants, and we highlight recently discovered components of gene silencing pathways in plants.
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Affiliation(s)
- Chin Hong Lee
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia
| | - Bernard J Carroll
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia
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Yang M, Xu Z, Zhao W, Liu Q, Li Q, Lu L, Liu R, Zhang X, Cui F. Rice stripe virus-derived siRNAs play different regulatory roles in rice and in the insect vector Laodelphax striatellus. BMC PLANT BIOLOGY 2018; 18:219. [PMID: 30286719 PMCID: PMC6172784 DOI: 10.1186/s12870-018-1438-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 09/23/2018] [Indexed: 05/20/2023]
Abstract
BACKGROUND Most plant viruses depend on vector insects for transmission. Upon viral infection, virus-derived small interfering RNAs (vsiRNAs) can target both viral and host transcripts. Rice stripe virus (RSV) is a persistent-propagative virus transmitted by the small brown planthopper (Laodelphax striatellus, Fallen) and can cause a severe disease on rice. RESULTS To investigate how vsiRNAs regulate gene expressions in the host plant and the insect vector, we analyzed the expression profiles of small RNAs (sRNAs) and mRNAs in RSV-infected rice and RSV-infected planthopper. We obtained 88,247 vsiRNAs in rice that were predominantly derived from the terminal regions of the RSV RNA segments, and 351,655 vsiRNAs in planthopper that displayed relatively even distributions on RSV RNA segments. 38,112 and 80,698 unique vsiRNAs were found only in rice and planthopper, respectively, while 14,006 unique vsiRNAs were found in both of them. Compared to mock-inoculated rice, 273 genes were significantly down-regulated genes (DRGs) in RSV-infected rice, among which 192 (70.3%) were potential targets of vsiRNAs based on sequence complementarity. Gene ontology (GO) analysis revealed that these 192 DRGs were enriched in genes involved in kinase activity, carbohydrate binding and protein binding. Similarly, 265 DRGs were identified in RSV-infected planthoppers, among which 126 (47.5%) were potential targets of vsiRNAs. These planthopper target genes were enriched in genes that are involved in structural constituent of cuticle, serine-type endopeptidase activity, and oxidoreductase activity. CONCLUSIONS Taken together, our results reveal that infection by the same virus can generate distinct vsiRNAs in different hosts to potentially regulate different biological processes, thus reflecting distinct virus-host interactions.
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Affiliation(s)
- Meiling Yang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Bei Chen Xi Lu 1-5, Beijing, 100101 China
| | - Zhongtian Xu
- Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, Shanghai, 201602 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Wan Zhao
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Bei Chen Xi Lu 1-5, Beijing, 100101 China
| | - Qing Liu
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Bei Chen Xi Lu 1-5, Beijing, 100101 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Qiong Li
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Bei Chen Xi Lu 1-5, Beijing, 100101 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Lu Lu
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Bei Chen Xi Lu 1-5, Beijing, 100101 China
| | - Renyi Liu
- Center for Agroforestry Mega Data Science and FAFU-UCR Joint Center for Horticultural Biology and Metabolomics, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, 350002 China
| | - Xiaoming Zhang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Bei Chen Xi Lu 1-5, Beijing, 100101 China
| | - Feng Cui
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Bei Chen Xi Lu 1-5, Beijing, 100101 China
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Bally J, Fishilevich E, Bowling AJ, Pence HE, Narva KE, Waterhouse PM. Improved insect-proofing: expressing double-stranded RNA in chloroplasts. PEST MANAGEMENT SCIENCE 2018; 74:1751-1758. [PMID: 29377554 PMCID: PMC6055657 DOI: 10.1002/ps.4870] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 01/19/2018] [Accepted: 01/19/2018] [Indexed: 05/11/2023]
Abstract
RNA interference (RNAi) was discovered almost 20 years ago and has been exploited worldwide to silence genes in plants and animals. A decade later, it was found that transforming plants with an RNAi construct targeting an insect gene could protect the plant against feeding by that insect. Production of double-stranded RNA (dsRNA) in a plant to affect the viability of a herbivorous animal is termed trans-kingdom RNAi (TK-RNAi). Since this pioneering work, there have been many further examples of successful TK-RNAi, but also reports of failed attempts and unrepeatable experiments. Recently, three laboratories have shown that producing dsRNA in a plant's chloroplast, rather than in its cellular cytoplasm, is a very effective way of delivering TK-RNAi. Our review examines this potentially game-changing approach and compares it with other transgenic insect-proofing schemes. © 2018 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
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Affiliation(s)
- Julia Bally
- Centre for Tropical Crops and BiocommoditiesQUT, Brisbane, QLDAustralia
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Montavon T, Kwon Y, Zimmermann A, Hammann P, Vincent T, Cognat V, Bergdoll M, Michel F, Dunoyer P. Characterization of DCL4 missense alleles provides insights into its ability to process distinct classes of dsRNA substrates. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 95:204-218. [PMID: 29682831 DOI: 10.1111/tpj.13941] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 03/10/2018] [Accepted: 04/05/2018] [Indexed: 05/10/2023]
Abstract
In the model plant Arabidopsis thaliana, four Dicer-like proteins (DCL1-4) mediate the production of various classes of small RNAs (sRNAs). Among these four proteins, DCL4 is by far the most versatile RNaseIII-like enzyme, and previously identified dcl4 missense alleles were shown to uncouple the production of the various classes of DCL4-dependent sRNAs. Yet little is known about the molecular mechanism behind this uncoupling. Here, by studying the subcellular localization, interactome and binding to the sRNA precursors of three distinct dcl4 missense alleles, we simultaneously highlight the absolute requirement of a specific residue in the helicase domain for the efficient production of all DCL4-dependent sRNAs, and identify, within the PAZ domain, an important determinant of DCL4 versatility that is mandatory for the efficient processing of intramolecular fold-back double-stranded RNA (dsRNA) precursors, but that is dispensable for the production of small interfering RNAs (siRNAs) from RDR-dependent dsRNA susbtrates. This study not only provides insights into the DCL4 mode of action, but also delineates interesting tools to further study the complexity of RNA silencing pathways in plants, and possibly other organisms.
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Affiliation(s)
- Thomas Montavon
- Institut de Biologie Moléculaire des Plantes du CNRS, UPR2357, Université de Strasbourg, F-67000, Strasbourg, France
| | - Yerim Kwon
- Institut de Biologie Moléculaire des Plantes du CNRS, UPR2357, Université de Strasbourg, F-67000, Strasbourg, France
| | - Aude Zimmermann
- Institut de Biologie Moléculaire des Plantes du CNRS, UPR2357, Université de Strasbourg, F-67000, Strasbourg, France
| | - Philippe Hammann
- Institut de Biologie Moléculaire et Cellulaire du CNRS, FRC1589, Plateforme Protéomique Strasbourg - Esplanade, Université de Strasbourg, F-67000, Strasbourg, France
| | - Timothée Vincent
- Institut de Biologie Moléculaire des Plantes du CNRS, UPR2357, Université de Strasbourg, F-67000, Strasbourg, France
| | - Valérie Cognat
- Institut de Biologie Moléculaire des Plantes du CNRS, UPR2357, Université de Strasbourg, F-67000, Strasbourg, France
| | - Marc Bergdoll
- Institut de Biologie Moléculaire des Plantes du CNRS, UPR2357, Université de Strasbourg, F-67000, Strasbourg, France
| | - Fabrice Michel
- Institut de Biologie Moléculaire des Plantes du CNRS, UPR2357, Université de Strasbourg, F-67000, Strasbourg, France
| | - Patrice Dunoyer
- Institut de Biologie Moléculaire des Plantes du CNRS, UPR2357, Université de Strasbourg, F-67000, Strasbourg, France
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Turco S, Golyaev V, Seguin J, Gilli C, Farinelli L, Boller T, Schumpp O, Pooggin MM. Small RNA-Omics for Virome Reconstruction and Antiviral Defense Characterization in Mixed Infections of Cultivated Solanum Plants. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2018; 31:707-723. [PMID: 29424662 DOI: 10.1094/mpmi-12-17-0301-r] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In plants, RNA silencing-based antiviral defense generates viral small RNAs (sRNAs) faithfully representing the viral genomes. We employed sRNA sequencing and bioinformatics (sRNA-omics) to characterize antiviral defense and to reconstruct the full genomic sequences and their variants in the evolving viral quasispecies in cultivated solanaceous plants carrying mixed infections. In naturally infected Solanum tuberosum (potato), one case study revealed a virome comprising Potato virus Y (genus Potyvirus) and Potato virus X (genus Potexvirus), which was reconstructed by de novo-assembling separate genome-size sRNA contigs. Another case study revealed a virome comprising NTN and O strains of Potato virus Y, whose sRNAs assembled in chimeric contigs, which could be disentangled on the basis of reference genome sequences. Both viromes were stable in vegetative potato progeny. In a cross-protection trial of Solanum lycopersicum (tomato), the supposedly protective mild strain CH2 of Pepino mosaic virus (genus Potexvirus) was tested for protection against strain LP of the same virus. Reciprocal mechanical inoculations eventually resulted in co-infection of all individual plants with CH2 and LP strains, reconstructed as separate sRNA contigs. LP invasions into CH2-preinfected plants and vice versa were accompanied by alterations of consensus genome sequences in viral quasispecies, indicating a potential risk of cross-protection measures. Additionally, the study also revealed, by reconstruction from sRNAs, the presence of the mechanically nontransmissible Southern tomato virus (genus Amalgavirus) in some plants. Our in-depth analysis of sRNA sizes, 5'-nucleotide frequencies and hotspot maps revealed similarities in sRNA-generating mechanisms in potato and tomato, differential silencing responses to virome components and potential for sRNA-directed cross-targeting between viral strains which could not, however, prevent the formation of stable viromes.
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Affiliation(s)
- Silvia Turco
- 1 Department of Environmental Sciences, Botany, Zurich-Basel Plant Science Center, University of Basel, Hebelstrasse 1, 4056 Basel, Switzerland
| | - Victor Golyaev
- 1 Department of Environmental Sciences, Botany, Zurich-Basel Plant Science Center, University of Basel, Hebelstrasse 1, 4056 Basel, Switzerland
| | - Jonathan Seguin
- 1 Department of Environmental Sciences, Botany, Zurich-Basel Plant Science Center, University of Basel, Hebelstrasse 1, 4056 Basel, Switzerland
| | | | | | - Thomas Boller
- 1 Department of Environmental Sciences, Botany, Zurich-Basel Plant Science Center, University of Basel, Hebelstrasse 1, 4056 Basel, Switzerland
| | | | - Mikhail M Pooggin
- 1 Department of Environmental Sciences, Botany, Zurich-Basel Plant Science Center, University of Basel, Hebelstrasse 1, 4056 Basel, Switzerland
- 5 INRA, UMR BGPI, 34398 Montpellier, France
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Pooggin MM, Ryabova LA. Ribosome Shunting, Polycistronic Translation, and Evasion of Antiviral Defenses in Plant Pararetroviruses and Beyond. Front Microbiol 2018; 9:644. [PMID: 29692761 PMCID: PMC5902531 DOI: 10.3389/fmicb.2018.00644] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 03/19/2018] [Indexed: 12/15/2022] Open
Abstract
Viruses have compact genomes and usually translate more than one protein from polycistronic RNAs using leaky scanning, frameshifting, stop codon suppression or reinitiation mechanisms. Viral (pre-)genomic RNAs often contain long 5′-leader sequences with short upstream open reading frames (uORFs) and secondary structure elements, which control both translation initiation and replication. In plants, viral RNA and DNA are targeted by RNA interference (RNAi) generating small RNAs that silence viral gene expression, while viral proteins are recognized by innate immunity and autophagy that restrict viral infection. In this review we focus on plant pararetroviruses of the family Caulimoviridae and describe the mechanisms of uORF- and secondary structure-driven ribosome shunting, leaky scanning and reinitiation after translation of short and long uORFs. We discuss conservation of these mechanisms in different genera of Caulimoviridae, including host genome-integrated endogenous viral elements, as well as in other viral families, and highlight a multipurpose use of the highly-structured leader sequence of plant pararetroviruses in regulation of translation, splicing, packaging, and reverse transcription of pregenomic RNA (pgRNA), and in evasion of RNAi. Furthermore, we illustrate how targeting of several host factors by a pararetroviral effector protein can lead to transactivation of viral polycistronic translation and concomitant suppression of antiviral defenses. Thus, activation of the plant protein kinase target of rapamycin (TOR) by the Cauliflower mosaic virus transactivator/viroplasmin (TAV) promotes reinitiation of translation after long ORFs on viral pgRNA and blocks antiviral autophagy and innate immunity responses, while interaction of TAV with the plant RNAi machinery interferes with antiviral silencing.
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Affiliation(s)
- Mikhail M Pooggin
- INRA, UMR Biologie et Génétique des Interactions Plante-Parasite, Montpellier, France
| | - Lyubov A Ryabova
- Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique, UPR 2357, Université de Strasbourg, Strasbourg, France
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