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Li J, Zhang BS, Wu HW, Liu CL, Guo HS, Zhao JH. The RNA-binding domain of DCL3 is required for long-distance RNAi signaling. ABIOTECH 2024; 5:17-28. [PMID: 38576436 PMCID: PMC10987413 DOI: 10.1007/s42994-023-00124-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 10/27/2023] [Indexed: 04/06/2024]
Abstract
Small RNA (sRNA)-mediated RNA silencing (also known as RNA interference, or RNAi) is a conserved mechanism in eukaryotes that includes RNA degradation, DNA methylation, heterochromatin formation and protein translation repression. In plants, sRNAs can move either cell-to-cell or systemically, thereby acting as mobile silencing signals to trigger noncell autonomous silencing. However, whether and what proteins are also involved in noncell autonomous silencing have not been elucidated. In this study, we utilized a previously reported inducible RNAi plant, PDSi, which can induce systemic silencing of the endogenous PDS gene, and we demonstrated that DCL3 is involved in systemic PDS silencing through its RNA binding activity. We confirmed that the C-terminus of DCL3, including the predicted RNA-binding domain, is capable of binding short RNAs. Mutations affecting RNA binding, but not processing activity, reduced systemic PDS silencing, indicating that DCL3 binding to RNAs is required for the induction of systemic silencing. Cucumber mosaic virus infection assays showed that the RNA-binding activity of DCL3 is required for antiviral RNAi in systemically noninoculated leaves. Our findings demonstrate that DCL3 acts as a signaling agent involved in noncell autonomous silencing and an antiviral effect in addition to its previously known function in the generation of 24-nucleotide sRNAs. Supplementary Information The online version contains supplementary material available at 10.1007/s42994-023-00124-6.
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Affiliation(s)
- Jie Li
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101 China
- CAS Center for Excellence in Biotic Interactions, University of the Chinese Academy of Sciences, Beijing, 100049 China
| | - Bo-Sen Zhang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101 China
- CAS Center for Excellence in Biotic Interactions, University of the Chinese Academy of Sciences, Beijing, 100049 China
| | - Hua-Wei Wu
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101 China
- CAS Center for Excellence in Biotic Interactions, University of the Chinese Academy of Sciences, Beijing, 100049 China
| | - Cheng-Lan Liu
- Qilu Zhongke Academy of Modern Microbiology Technology, Jinan, 250022 China
| | - Hui-Shan Guo
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101 China
- CAS Center for Excellence in Biotic Interactions, University of the Chinese Academy of Sciences, Beijing, 100049 China
| | - Jian-Hua Zhao
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101 China
- CAS Center for Excellence in Biotic Interactions, University of the Chinese Academy of Sciences, Beijing, 100049 China
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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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Zhao JH, Guo HS. RNA silencing: From discovery and elucidation to application and perspectives. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2022; 64:476-498. [PMID: 34964265 DOI: 10.1111/jipb.13213] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 12/26/2021] [Indexed: 06/14/2023]
Abstract
RNA silencing (or RNA interference, RNAi) is a conserved mechanism for regulating gene expression in eukaryotes. The discovery of natural trans-kingdom RNAi indicated that small RNAs act as signaling molecules and enable communication between organisms in different kingdoms. The phenomenon and potential mechanisms of trans-kingdom RNAi are among the most exciting research topics. To better understand trans-kingdom RNAi, we review the history of the discovery and elucidation of RNAi mechanisms. Based on canonical RNAi mechanisms, we summarize the major points of divergence around RNAi pathways in the main eukaryotes' kingdoms, including plants, animals, and fungi. We review the representative incidents associated with the mechanisms and applications of trans-kingdom RNAi in crop protection, and discuss the critical factors that should be considered to develop successful trans-kingdom RNAi-based crop protection strategies.
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Affiliation(s)
- Jian-Hua Zhao
- State Key Laboratory of Plant Genomics, Institute of Microbiology, the Chinese Academy of Sciences, Beijing, 100101, China
- CAS Center for Excellence in Biotic Interactions, University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Hui-Shan Guo
- State Key Laboratory of Plant Genomics, Institute of Microbiology, the Chinese Academy of Sciences, Beijing, 100101, China
- CAS Center for Excellence in Biotic Interactions, University of the Chinese Academy of Sciences, Beijing, 100049, China
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Pei L, Zhang L, Li J, Shen C, Qiu P, Tu L, Zhang X, Wang M. Tracing the origin and evolution history of methylation-related genes in plants. BMC PLANT BIOLOGY 2019; 19:307. [PMID: 31299897 PMCID: PMC6624907 DOI: 10.1186/s12870-019-1923-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 07/03/2019] [Indexed: 05/20/2023]
Abstract
BACKGROUND DNA methylation is a crucial epigenetic modification, which is involved in many biological processes, including gene expression regulation, embryonic development, cell differentiation and genomic imprinting etc. And it also involves many key regulatory genes in eukaryotes. By tracing the evolutionary history of methylation-related genes, we can understand the origin and expansion time of these genes, which helps to understand the evolutionary history of plants, and we can also understand the changes of DNA methylation patterns in different species. However, most studies on the evolution of methylation-related genes failed to be carried out for the whole DNA methylation pathway. RESULTS In this study, we conducted a comprehensive identification of 33 methylation-related genes in 77 species, and investigated gene origin and evolution throughout the plant kingdom. We found that the origin of genes responsible for methylation maintenance and demethylation evolved early, while most de novo methylation-related genes appeared late. The methylation-related genes were expanded by whole genome duplication and tandem replication, but were also accompanied by a large number of gene absence events in different species. The gene length and intron length varied a lot in different species, but exon structure and functional domains were relatively conserved. The phylogenetic relationships of methylation-related genes were traced to reveal the evolution history of DNA methylation in different species. The expression patterns of methylation-related genes have changed during the evolution of species, and the expression patterns of these genes in different species can be clustered into four categories. CONCLUSIONS The study describes a global characterization of DNA methylation-related genes in the plant kingdom. The similarities and differences in origin time, gene structure and phylogenetic relationship of these genes lead us to understand the evolutionary conservation and dynamics of DNA methylation in plants.
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Affiliation(s)
- Liuling Pei
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070 Hubei China
| | - Lin Zhang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070 Hubei China
| | - Jianying Li
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070 Hubei China
| | - Chao Shen
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070 Hubei China
| | - Ping Qiu
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070 Hubei China
| | - Lili Tu
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070 Hubei China
| | - Xianlong Zhang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070 Hubei China
| | - Maojun Wang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070 Hubei China
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Liu X, Zhao J, Guo HS. IBM1-dependent H3K9 demethylation enables self-silencing of an exogenous silencer for the non-cell autonomous silencing of an endogenous target gene. J Genet Genomics 2019; 46:149-153. [PMID: 30935857 DOI: 10.1016/j.jgg.2019.02.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 02/19/2019] [Indexed: 11/18/2022]
Affiliation(s)
- Xiaolan Liu
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China; College of Life Sciences, University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Jianhua Zhao
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Hui-Shan Guo
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China; College of Life Sciences, University of the Chinese Academy of Sciences, Beijing, 100049, China.
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Guo Q, Liu Q, Smith NA, Liang G, Wang MB. RNA Silencing in Plants: Mechanisms, Technologies and Applications in Horticultural Crops. Curr Genomics 2016; 17:476-489. [PMID: 28217004 PMCID: PMC5108043 DOI: 10.2174/1389202917666160520103117] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 11/30/2015] [Accepted: 12/03/2015] [Indexed: 12/20/2022] Open
Abstract
Understanding the fundamental nature of a molecular process or a biological pathway is often a catalyst for the development of new technologies in biology. Indeed, studies from late 1990s to early 2000s have uncovered multiple overlapping but functionally distinct RNA silencing pathways in plants, including the posttranscriptional microRNA and small interfering RNA pathways and the transcriptional RNA-directed DNA methylation pathway. These findings have in turn been exploited for developing artificial RNA silencing technologies such as hairpin RNA, artificial microRNA, intrinsic direct repeat, 3' UTR inverted repeat, artificial trans-acting siRNA, and virus-induced gene silencing technologies. Some of these RNA silencing technologies, such as the hairpin RNA technology, have already been widely used for genetic improvement of crop plants in agriculture. For horticultural plants, RNA silencing technologies have been used to increase disease and pest resistance, alter plant architecture and flowering time, improve commercial traits of fruits and flowers, enhance nutritional values, remove toxic compounds and allergens, and develop high-value industrial products. In this article we aim to provide an overview of the RNA silencing pathways in plants, summarize the existing RNA silencing technologies, and review the current progress in applying these technologies for the improvement of agricultural crops particularly horticultural crops.
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Affiliation(s)
- Qigao Guo
- College of Horticulture & Landscape Architecture, Southwest University, Chongqing, 400716, China
| | - Qing Liu
- Commonwealth Scientific and Industrial Research Organisation Agriculture (CSIRO), ACT 2601, Australia
| | - Neil A Smith
- Commonwealth Scientific and Industrial Research Organisation Agriculture (CSIRO), ACT 2601, Australia
| | - Guolu Liang
- College of Horticulture & Landscape Architecture, Southwest University, Chongqing, 400716, China
| | - Ming-Bo Wang
- Commonwealth Scientific and Industrial Research Organisation Agriculture (CSIRO), ACT 2601, Australia
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Chen X, Chen G, Truksa M, Snyder CL, Shah S, Weselake RJ. Glycerol-3-phosphate acyltransferase 4 is essential for the normal development of reproductive organs and the embryo in Brassica napus. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:4201-15. [PMID: 24821955 PMCID: PMC4112632 DOI: 10.1093/jxb/eru199] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The enzyme sn-glycerol-3-phosphate acyltransferase 4 (GPAT4) is involved in the biosynthesis of plant lipid poly-esters. The present study further characterizes the enzymatic activities of three endoplasmic reticulum-bound GPAT4 isoforms of Brassica napus and examines their roles in the development of reproductive organs and the embryo. All three BnGPAT4 isoforms exhibited sn-2 acyltransferase and phosphatase activities with dicarboxylic acid-CoA as acyl donor. When non-substituted acyl-CoA was used as acyl donor, the rate of acylation was considerably lower and phosphatase activity was not manifested. RNA interference (RNAi)-mediated down-regulation of all GPAT4 homologues in B. napus under the control of the napin promoter caused abnormal development of several reproductive organs and reduced seed set. Microscopic examination and reciprocal crosses revealed that both pollen grains and developing embryo sacs of the B. napus gpat4 lines were affected. The gpat4 mature embryos showed decreased cutin content and altered monomer composition. The defective embryo development further affected the oil body morphology, oil content, and fatty acid composition in gpat4 seeds. These results suggest that GPAT4 has a critical role in the development of reproductive organs and the seed of B. napus.
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Affiliation(s)
- Xue Chen
- Agricultural Lipid Biotechnology Program, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada T6G 2P5
| | - Guanqun Chen
- Agricultural Lipid Biotechnology Program, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada T6G 2P5
| | - Martin Truksa
- Agricultural Lipid Biotechnology Program, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada T6G 2P5
| | - Crystal L Snyder
- Agricultural Lipid Biotechnology Program, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada T6G 2P5
| | - Saleh Shah
- Plant Biotechnology, Alberta Innovates-Technology Futures, Vegreville, Alberta, Canada T9C 1T4
| | - Randall J Weselake
- Agricultural Lipid Biotechnology Program, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada T6G 2P5
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McHale M, Eamens AL, Finnegan EJ, Waterhouse PM. A 22-nt artificial microRNA mediates widespread RNA silencing in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2013; 76:519-29. [PMID: 23937661 PMCID: PMC4241025 DOI: 10.1111/tpj.12306] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2013] [Revised: 07/26/2013] [Accepted: 08/05/2013] [Indexed: 05/03/2023]
Abstract
It is known that 22-nucleotide (nt) microRNAs (miRNAs) derived from asymmetric duplexes trigger phased small-interfering RNA (phasiRNA) production from complementary targets. Here we investigate the efficacy of 22-nt artificial miRNA (amiRNA)-mediated RNA silencing relative to conventional hairpin RNA (hpRNA) and 21-nt amiRNA-mediated RNA silencing. CHALCONE SYNTHASE (CHS) was selected as a target in Arabidopsis thaliana due to the obvious and non-lethal loss of anthocyanin accumulation upon widespread RNA silencing. Over-expression of CHS in the pap1-D background facilitated visual detection of both local and systemic RNA silencing. RNA silencing was initiated in leaf tissues from hpRNA and amiRNA plant expression vectors under the control of an Arabidopsis RuBisCo small subunit 1A promoter (SSU). In this system, hpRNA expression triggered CHS silencing in most leaf tissues but not in roots or seed coats. Similarly, 21-nt amiRNA expression from symmetric miRNA/miRNA* duplexes triggered CHS silencing in all leaf tissues but not in roots or seed coats. However, 22-nt amiRNA expression from an asymmetric duplex triggered CHS silencing in all tissues, including roots and seed coats, in the majority of plant lines. This widespread CHS silencing required RNA-DEPENDENT RNA POLYMERASE6-mediated accumulation of phasiRNAs from the endogenous CHS transcript. These results demonstrate the efficacy of asymmetric 22-nt amiRNA-directed RNA silencing and associated phasiRNA production and activity, in mediating widespread RNA silencing of an endogenous target gene. Asymmetric 22-nt amiRNA-directed RNA silencing requires little modification of existing amiRNA technology and is expected to be effective in suppressing other genes and/or members of gene families.
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Affiliation(s)
- Marcus McHale
- University of Sydney, Waterhouse LaboratoryLvl 8 Biochemistry Bldg G08, Sydney, NSW, 2006, Australia
| | - Andrew L Eamens
- University of Sydney, Waterhouse LaboratoryLvl 8 Biochemistry Bldg G08, Sydney, NSW, 2006, Australia
- University Drive CallaghanB105, Biology Building, Callaghan, NSW, 2308, Australia
| | - E Jean Finnegan
- CSIRO Plant Industry - Black Mountain
LaboratoriesClunies Ross Street, Black Mountain, ACT, 2601, Australia
| | - Peter M Waterhouse
- University of Sydney, Waterhouse LaboratoryLvl 8 Biochemistry Bldg G08, Sydney, NSW, 2006, Australia
- * For correspondence (e-mail
)
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Parent JS, Martínez de Alba AE, Vaucheret H. The origin and effect of small RNA signaling in plants. FRONTIERS IN PLANT SCIENCE 2012; 3:179. [PMID: 22908024 PMCID: PMC3414853 DOI: 10.3389/fpls.2012.00179] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Accepted: 07/23/2012] [Indexed: 05/18/2023]
Abstract
Given their sessile condition, land plants need to integrate environmental cues rapidly and send signal throughout the organism to modify their metabolism accordingly. Small RNA (sRNA) molecules are among the messengers that plant cells use to carry such signals. These molecules originate from fold-back stem-loops transcribed from endogenous loci or from perfect double-stranded RNA produced through the action of RNA-dependent RNA polymerases. Once produced, sRNAs associate with Argonaute (AGO) and other proteins to form the RNA-induced silencing complex (RISC) that executes silencing of complementary RNA molecules. Depending on the nature of the RNA target and the AGO protein involved, RISC triggers either DNA methylation or chromatin modification (leading to transcriptional gene silencing, TGS) or RNA cleavage or translational inhibition (leading to post-transcriptional gene silencing, PTGS). In some cases, sRNAs move to neighboring cells and/or to the vascular tissues for long-distance trafficking. Many genes are involved in the biogenesis of sRNAs and recent studies have shown that both their origin and their protein partners have great influence on their activity and range. Here we summarize the work done to uncover the mode of action of the different classes of sRNA with special emphasis on their movement and how plants can take advantage of their mobility. We also review the various genetic requirements needed for production, movement and perception of the silencing signal.
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Affiliation(s)
| | | | - Hervé Vaucheret
- *Correspondence: Hervé Vaucheret, Institut Jean-Pierre Bourgin, INRA Centre de Versailles-Grignon, 78026 Versailles Cedex, France. e-mail:
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