1
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Zhang D, Jue D, Smith N, Zhong C, Finnegan EJ, de Feyter R, Wang MB, Greaves I. Asymmetric bulges within hairpin RNA transgenes influence small RNA size, secondary siRNA production and viral defence. Nucleic Acids Res 2024; 52:9904-9916. [PMID: 38967001 PMCID: PMC11381321 DOI: 10.1093/nar/gkae573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 05/28/2024] [Accepted: 06/24/2024] [Indexed: 07/06/2024] Open
Abstract
Small RNAs (sRNAs) are essential for normal plant development and range in size classes of 21-24 nucleotides. The 22nt small interfering RNAs (siRNAs) and miRNAs are processed by Dicer-like 2 (DCL2) and DCL1 respectively and can initiate secondary siRNA production from the target transcript. 22nt siRNAs are under-represented due to competition between DCL2 and DCL4, while only a small number of 22nt miRNAs exist. Here we produce abundant 22nt siRNAs and other siRNA size classes using long hairpin RNA (hpRNA) transgenes. By introducing asymmetric bulges into the antisense strand of hpRNA, we shifted the dominant siRNA size class from 21nt of the traditional hpRNA to 22, 23 and 24nt of the asymmetric hpRNAs. The asymmetric hpRNAs effectively silenced a β-glucuronidase (GUS) reporter transgene and the endogenous ethylene insensitive-2 (EIN2) and chalcone synthase (CHS) genes. Furthermore, plants containing the asymmetric hpRNA transgenes showed increased amounts of 21nt siRNAs downstream of the hpRNA target site compared to plants with the traditional hpRNA transgenes. This indicates that these asymmetric hpRNAs are more effective at inducing secondary siRNA production to amplify silencing signals. The 22nt asymmetric hpRNA constructs enhanced virus resistance in plants compared to the traditional hpRNA constructs.
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Affiliation(s)
- Daai Zhang
- Agriculture and Food Research Unit, CSIRO, Clunies Ross Street, Acton, ACT 2601, Australia
| | - Dengwei Jue
- Agriculture and Food Research Unit, CSIRO, Clunies Ross Street, Acton, ACT 2601, Australia
- Chongqing Key Laboratory of Economic Plant Biotechnology, Collaborative Innovation Center of Special Plant Industry in Chongqing, College of Landscape Architecture and Life Science/Institute of Special Plants, Chongqing University of Arts and Sciences, Yongchuan 402160, China
| | - Neil Smith
- Agriculture and Food Research Unit, CSIRO, Clunies Ross Street, Acton, ACT 2601, Australia
| | - Chengcheng Zhong
- Agriculture and Food Research Unit, CSIRO, Clunies Ross Street, Acton, ACT 2601, Australia
| | - E Jean Finnegan
- Agriculture and Food Research Unit, CSIRO, Clunies Ross Street, Acton, ACT 2601, Australia
| | - Robert de Feyter
- Agriculture and Food Research Unit, CSIRO, Clunies Ross Street, Acton, ACT 2601, Australia
| | - Ming-Bo Wang
- Agriculture and Food Research Unit, CSIRO, Clunies Ross Street, Acton, ACT 2601, Australia
| | - Ian Greaves
- Agriculture and Food Research Unit, CSIRO, Clunies Ross Street, Acton, ACT 2601, Australia
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2
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Berube B, Ernst E, Cahn J, Roche B, de Santis Alves C, Lynn J, Scheben A, Grimanelli D, Siepel A, Ross-Ibarra J, Kermicle J, Martienssen RA. Teosinte Pollen Drive guides maize diversification and domestication by RNAi. Nature 2024; 633:380-388. [PMID: 39112710 PMCID: PMC11390486 DOI: 10.1038/s41586-024-07788-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 07/04/2024] [Indexed: 08/17/2024]
Abstract
Selfish genetic elements contribute to hybrid incompatibility and bias or 'drive' their own transmission1,2. Chromosomal drive typically functions in asymmetric female meiosis, whereas gene drive is normally post-meiotic and typically found in males. Here, using single-molecule and single-pollen genome sequencing, we describe Teosinte Pollen Drive, an instance of gene drive in hybrids between maize (Zea mays ssp. mays) and teosinte mexicana (Z. mays ssp. mexicana) that depends on RNA interference (RNAi). 22-nucleotide small RNAs from a non-coding RNA hairpin in mexicana depend on Dicer-like 2 (Dcl2) and target Teosinte Drive Responder 1 (Tdr1), which encodes a lipase required for pollen viability. Dcl2, Tdr1 and the hairpin are in tight pseudolinkage on chromosome 5, but only when transmitted through the male. Introgression of mexicana into early cultivated maize is thought to have been critical to its geographical dispersal throughout the Americas3, and a tightly linked inversion in mexicana spans a major domestication sweep in modern maize4. A survey of maize traditional varieties and sympatric populations of teosinte mexicana reveals correlated patterns of admixture among unlinked genes required for RNAi on at least four chromosomes that are also subject to gene drive in pollen from synthetic hybrids. Teosinte Pollen Drive probably had a major role in maize domestication and diversification, and offers an explanation for the widespread abundance of 'self' small RNAs in the germ lines of plants and animals.
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Affiliation(s)
- Benjamin Berube
- Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Evan Ernst
- Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Jonathan Cahn
- Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Benjamin Roche
- Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | | | - Jason Lynn
- Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Armin Scheben
- Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | | | - Adam Siepel
- Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Jeffrey Ross-Ibarra
- Department of Evolution and Ecology, Center for Population Biology and Genome Center, University of California at Davis, Davis, CA, USA
| | - Jerry Kermicle
- Laboratory of Genetics, University of Wisconsin, Madison, WI, USA
| | - Robert A Martienssen
- Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA.
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3
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Nielsen CPS, Arribas-Hernández L, Han L, Reichel M, Woessmann J, Daucke R, Bressendorff S, López-Márquez D, Andersen SU, Pumplin N, Schoof EM, Brodersen P. Evidence for an RNAi-independent role of Arabidopsis DICER-LIKE2 in growth inhibition and basal antiviral resistance. THE PLANT CELL 2024; 36:2289-2309. [PMID: 38466226 PMCID: PMC11132882 DOI: 10.1093/plcell/koae067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 12/13/2023] [Accepted: 01/28/2024] [Indexed: 03/12/2024]
Abstract
Flowering plant genomes encode four or five DICER-LIKE (DCL) enzymes that produce small interfering RNAs (siRNAs) and microRNAs, which function in RNA interference (RNAi). Different RNAi pathways in plants effect transposon silencing, antiviral defense, and endogenous gene regulation. DCL2 acts genetically redundantly with DCL4 to confer basal antiviral defense. However, DCL2 may also counteract DCL4 since knockout of DCL4 causes growth defects that are suppressed by DCL2 inactivation. Current models maintain that RNAi via DCL2-dependent siRNAs is the biochemical basis of both effects. Here, we report that DCL2-mediated antiviral resistance and growth defects cannot be explained by the silencing effects of DCL2-dependent siRNAs. Both functions are defective in genetic backgrounds that maintain high levels of DCL2-dependent siRNAs, either with specific point mutations in DCL2 or with reduced DCL2 dosage because of heterozygosity for dcl2 knockout alleles. Intriguingly, all DCL2 functions require its catalytic activity, and the penetrance of DCL2-dependent growth phenotypes in dcl4 mutants correlates with DCL2 protein levels but not with levels of major DCL2-dependent siRNAs. We discuss this requirement and correlation with catalytic activity but not with resulting siRNAs, in light of other findings that reveal a DCL2 function in innate immunity activation triggered by cytoplasmic double-stranded RNA.
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Affiliation(s)
- Carsten Poul Skou Nielsen
- Copenhagen Plant Science Center, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark
| | - Laura Arribas-Hernández
- Copenhagen Plant Science Center, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark
| | - Lijuan Han
- Copenhagen Plant Science Center, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark
| | - Marlene Reichel
- Copenhagen Plant Science Center, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark
| | - Jakob Woessmann
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Bygningstorvet, DK-2800 Lyngby, Denmark
| | - Rune Daucke
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Bygningstorvet, DK-2800 Lyngby, Denmark
| | - Simon Bressendorff
- Copenhagen Plant Science Center, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark
| | - Diego López-Márquez
- Copenhagen Plant Science Center, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark
| | - Stig Uggerhøj Andersen
- Department of Molecular Biology and Genetics, Aarhus University, Universitetsbyen 81, DK-8000 Aarhus C, Denmark
| | - Nathan Pumplin
- Swiss Federal Institute of Technology, Institute of Molecular Plant Biology, Universitätsstrasse 2, CH-8092 Zürich, Switzerland
| | - Erwin M Schoof
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Bygningstorvet, DK-2800 Lyngby, Denmark
| | - Peter Brodersen
- Copenhagen Plant Science Center, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark
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4
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Naim D, Ahsan A, Imtiaj A, Mollah NH. Genome-wide identification and in silico characterization of major RNAi gene families in date palm (Phoenix dactylifera). BMC Genom Data 2024; 25:31. [PMID: 38491426 PMCID: PMC10943882 DOI: 10.1186/s12863-024-01217-x] [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: 05/13/2023] [Accepted: 03/06/2024] [Indexed: 03/18/2024] Open
Abstract
BACKGROUND Dates contain various minerals that are essential for good health. The major RNA interference (RNAi) gene families play a vital role in plant growth and development by controlling the expression of protein-coding genes against different biotic and abiotic stresses. However, these gene families for date palm are not yet studied. Therefore, this study has explored major RNAi genes and their characteristics in date palm. RESULTS We have identified 4 PdDCLs, 7 PdAGOs, and 3 PdRDRs as RNAi proteins from the date palm genome by using AtRNAi genes as query sequences in BLASTp search. Domain analysis of predicted RNAi genes has revealed the Helicase_C, Dicer_dimer, PAZ, RNase III, and Piwi domains that are associated with the gene silencing mechanisms. Most PdRNAi proteins have been found in the nucleus and cytosol associated with the gene silencing actions. The gene ontology (GO) enrichment analysis has revealed some important GO terms including RNA interference, dsRNA fragmentation, and ribonuclease_III activity that are related to the protein-coding gene silencing mechanisms. Gene regulatory network (GRN) analysis has identified PAZ and SNF2 as the transcriptional regulators of PdRNAi genes. Top-ranked 10 microRNAs including Pda-miR156b, Pda-miR396a, Pda-miR166a, Pda-miR167d, and Pda-miR529a have been identified as the key post-transcriptional regulators of PdRNAi genes that are associated with different biotic/abiotic stresses. The cis-acting regulatory element analysis of PdRNAi genes has detected some vital cis-acting elements including ABRE, MBS, MYB, MYC, Box-4, G-box, I-box, and STRE that are linked with different abiotic stresses. CONCLUSION The results of this study might be valuable resources for the improvement of different characteristics in date palm by further studies in wet-lab.
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Affiliation(s)
- Darun Naim
- Bioinformatics Lab, Department of Statistics, Faculty of Science, University of Rajshahi, 6205, Rajshahi, Bangladesh
- Department of Botany, Faculty of Biological Sciences, University of Rajshahi, 6205, Rajshahi, Bangladesh
| | - Asif Ahsan
- Bioinformatics Lab, Department of Statistics, Faculty of Science, University of Rajshahi, 6205, Rajshahi, Bangladesh
| | - Ahmed Imtiaj
- Department of Botany, Faculty of Biological Sciences, University of Rajshahi, 6205, Rajshahi, Bangladesh
| | - Nurul Haque Mollah
- Bioinformatics Lab, Department of Statistics, Faculty of Science, University of Rajshahi, 6205, Rajshahi, Bangladesh.
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5
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Niu J, Chen R, Wang JJ. RNA interference in insects: the link between antiviral defense and pest control. INSECT SCIENCE 2024; 31:2-12. [PMID: 37162315 DOI: 10.1111/1744-7917.13208] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 03/27/2023] [Accepted: 04/10/2023] [Indexed: 05/11/2023]
Abstract
RNA interference (RNAi) is a form of gene silencing triggered by double-stranded RNA (dsRNA) that operates in all eukaryotic cells. RNAi has been widely investigated in insects to determine the underlying molecular mechanism, to investigate its role in systemic antiviral defense, and to develop strategies for pest control. When insect cells are infected by viruses, viral dsRNA signatures trigger a local RNAi response to block viral replication and generate virus-derived DNA that confers systemic immunity. RNAi-based insect pest control involves the application of exogenous dsRNA targeting genes essential for insect development or survival, but the efficacy of this approach has limited potency in many pests through a combination of rapid dsRNA degradation, inefficient dsRNA uptake/processing, and ineffective RNAi machinery. This could be addressed by dsRNA screening and evaluation, focusing on dsRNA design and off-target management, as well as dsRNA production and delivery. This review summarizes recent progress to determine the role of RNAi in antiviral defense and as a pest control strategy in insects, addressing gaps between our fundamental understanding of the RNAi mechanism and the exploitation of RNAi-based pest control strategies.
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Affiliation(s)
- Jinzhi Niu
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), Southwest University, Chongqing, China
| | - Ruoyu Chen
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), Southwest University, Chongqing, China
| | - Jin-Jun Wang
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), Southwest University, Chongqing, China
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6
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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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7
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Berube B, Ernst E, Cahn J, Roche B, de Santis Alves C, Lynn J, Scheben A, Siepel A, Ross-Ibarra J, Kermicle J, Martienssen R. Teosinte Pollen Drive guides maize diversification and domestication by RNAi. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.12.548689. [PMID: 37503269 PMCID: PMC10370002 DOI: 10.1101/2023.07.12.548689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Meiotic drivers subvert Mendelian expectations by manipulating reproductive development to bias their own transmission. Chromosomal drive typically functions in asymmetric female meiosis, while gene drive is normally postmeiotic and typically found in males. Using single molecule and single-pollen genome sequencing, we describe Teosinte Pollen Drive, an instance of gene drive in hybrids between maize (Zea mays ssp. mays) and teosinte mexicana (Zea mays ssp. mexicana), that depends on RNA interference (RNAi). 22nt small RNAs from a non-coding RNA hairpin in mexicana depend on Dicer-Like 2 (Dcl2) and target Teosinte Drive Responder 1 (Tdr1), which encodes a lipase required for pollen viability. Dcl2, Tdr1, and the hairpin are in tight pseudolinkage on chromosome 5, but only when transmitted through the male. Introgression of mexicana into early cultivated maize is thought to have been critical to its geographical dispersal throughout the Americas, and a tightly linked inversion in mexicana spans a major domestication sweep in modern maize. A survey of maize landraces and sympatric populations of teosinte mexicana reveals correlated patterns of admixture among unlinked genes required for RNAi on at least 4 chromosomes that are also subject to gene drive in pollen from synthetic hybrids. Teosinte Pollen Drive likely played a major role in maize domestication and diversification, and offers an explanation for the widespread abundance of "self" small RNAs in the germlines of plants and animals.
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Affiliation(s)
- Benjamin Berube
- Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor NY11724
| | - Evan Ernst
- Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor NY11724
| | - Jonathan Cahn
- Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor NY11724
| | - Benjamin Roche
- Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor NY11724
| | | | - Jason Lynn
- Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor NY11724
| | - Armin Scheben
- Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor NY11724
| | - Adam Siepel
- Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor NY11724
| | - Jeffrey Ross-Ibarra
- Dept. of Evolution & Ecology, Center for Population Biology and Genome Center, University of California, Davis CA
| | - Jerry Kermicle
- Laboratory of Genetics, University of Wisconsin, Madison WI
| | - Rob Martienssen
- Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor NY11724
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8
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Chen L, Liu Y, Li S, Ji Y, Sun F, Zou B. DICER-LIKE2 Plays a Crucial Role in Rice Stripe Virus Coat Protein-Mediated Virus Resistance in Arabidopsis. Viruses 2023; 15:2239. [PMID: 38005916 PMCID: PMC10675384 DOI: 10.3390/v15112239] [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: 10/08/2023] [Revised: 11/03/2023] [Accepted: 11/08/2023] [Indexed: 11/26/2023] Open
Abstract
Virus coat protein (CP)-mediated resistance is considered an effective antiviral defense strategy that has been used to develop robust resistance to viral infection. Rice stripe virus (RSV) causes significant losses in rice production in eastern Asia. We previously showed that the overexpression of RSV CP in Arabidopsis plants results in immunity to RSV infection, using the RSV-Arabidopsis pathosystem, and this CP-mediated viral resistance depends on the function of DCLs and is mostly involved in RNA silencing. However, the special role of DCLs in producing t-siRNAs in CP transgenic Arabidopsis plants is not fully understood. In this study, we show that RSV CP transgenic Arabidopsis plants with the dcl2 mutant background exhibited similar virus susceptibility to non-transgenic plants and were accompanied by the absence of transgene-derived small interfering RNAs (t-siRNAs) from the CP region. The dcl2 mutation eliminated the accumulation of CP-derived t-siRNAs, including those generated by other DCL enzymes. In contrast, we also developed RSV CP transgenic Arabidopsis plants with the dcl4 mutant background, and these CP transgenic plants showed immunity to virus infection and accumulated comparable amounts of CP-derived t-siRNAs to CP transgenic Arabidopsis plants with the wild-type background except for a significant increase in the abundance of 22 nt t-siRNA reads. Overall, our data indicate that DCL2 plays an essential, as opposed to redundant, role in CP-derived t-siRNA production and induces virus resistance in RSV CP transgenic Arabidopsis plants.
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Affiliation(s)
- Li Chen
- The State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Nanjing Agricultural University, Nanjing 210095, China;
- Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base, Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China; (Y.L.); (S.L.); (Y.J.)
| | - Yanan Liu
- Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base, Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China; (Y.L.); (S.L.); (Y.J.)
| | - Shuo Li
- Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base, Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China; (Y.L.); (S.L.); (Y.J.)
| | - Yinghua Ji
- Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base, Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China; (Y.L.); (S.L.); (Y.J.)
| | - Feng Sun
- Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base, Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China; (Y.L.); (S.L.); (Y.J.)
| | - Baohong Zou
- The State Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Nanjing Agricultural University, Nanjing 210095, China;
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9
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Chiang CP, Li JL, Chiou TJ. Dose-dependent long-distance movement of microRNA399 duplex regulates phosphate homeostasis in Arabidopsis. THE NEW PHYTOLOGIST 2023; 240:802-814. [PMID: 37547977 DOI: 10.1111/nph.19182] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Accepted: 07/13/2023] [Indexed: 08/08/2023]
Abstract
MicroRNA399 (miR399), a phosphate (Pi) starvation-induced long-distance signal, is first produced in shoots and moves to roots to suppress PHO2 encoding a ubiquitin conjugase, leading to enhanced Pi uptake and root-to-shoot translocation. However, the molecular mechanism underlying miR399 long-distance movement remains elusive. Hypocotyl grafting with various Arabidopsis mutants or transgenic lines expressing artificial miR399f was employed. The movement of miR399 across graft junction and the rootstock PHO2 transcript and scion Pi levels were analyzed to elucidate the potential factors involved. Our results showed that miR399f precursors are cell-autonomous and mature miR399f movement is independent of its biogenesis, sequence context, and length (21 or 22 nucleotides). Expressing viral silencing suppressor P19 in the root stele or blocking unloading in the root phloem pore pericycle (PPP) antagonized its silencing effect, suggesting that the miR399f/miR399f* duplex is a mobile entity unloaded through PPP. Notably, the scion miR399f level positively correlates with its amount translocated to rootstocks, implying dose-dependent movement. This study uncovers the molecular basis underlying the miR399-mediated long-distance silencing in coordinating shoot Pi demand with Pi acquisition and translocation activities in the roots.
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Affiliation(s)
- Chih-Pin Chiang
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, 11529, Taiwan
| | - Jia-Ling Li
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, 11529, Taiwan
| | - Tzyy-Jen Chiou
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, 11529, Taiwan
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10
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Kanno T, Chiou P, Wu MT, Lin WD, Matzke A, Matzke M. A GFP splicing reporter in a coilin mutant background reveals links between alternative splicing, siRNAs, and coilin function in Arabidopsis thaliana. G3 (BETHESDA, MD.) 2023; 13:jkad175. [PMID: 37539868 PMCID: PMC10542627 DOI: 10.1093/g3journal/jkad175] [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: 02/25/2023] [Revised: 02/25/2023] [Accepted: 06/30/2023] [Indexed: 08/05/2023]
Abstract
Coilin is a scaffold protein essential for the structure of Cajal bodies, which are nucleolar-associated, nonmembranous organelles that coordinate the assembly of nuclear ribonucleoproteins (RNPs) including spliceosomal snRNPs. To study coilin function in plants, we conducted a genetic suppressor screen using a coilin (coi1) mutant in Arabidopsis thaliana and performed an immunoprecipitation-mass spectrometry analysis on coilin protein. The coi1 mutations modify alternative splicing of a GFP reporter gene, resulting in a hyper-GFP phenotype in young coi1 seedlings relative to the intermediate wild-type level. As shown here, this hyper-GFP phenotype is extinguished in older coi1 seedlings by posttranscriptional gene silencing triggered by siRNAs derived from aberrant splice variants of GFP pre-mRNA. In the coi1 suppressor screen, we identified suppressor mutations in WRAP53, a putative coilin-interacting protein; SMU2, a predicted splicing factor; and ZCH1, an incompletely characterized zinc finger protein. These suppressor mutations return the hyper-GFP fluorescence of young coi1 seedlings to the intermediate wild-type level. Additionally, coi1 zch1 mutants display more extensive GFP silencing and elevated levels of GFP siRNAs, suggesting the involvement of wild-type ZCH1 in siRNA biogenesis or stability. The immunoprecipitation-mass spectrometry analysis reinforced the roles of coilin in pre-mRNA splicing, nucleolar chromatin structure, and rRNA processing. The participation of coilin in these processes, at least some of which incorporate small RNAs, supports the hypothesis that coilin provides a chaperone for small RNA trafficking. Our study demonstrates the usefulness of the GFP splicing reporter for investigating alternative splicing, ribosome biogenesis, and siRNA-mediated silencing in the context of coilin function.
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Affiliation(s)
- Tatsuo Kanno
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 115201, Taiwan
| | - Phebe Chiou
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 115201, Taiwan
| | - Ming-Tsung Wu
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 115201, Taiwan
- Genenet Technology (UK) Limited, 128 City Road, London EC1V 2NX, UK
| | - Wen-Dar Lin
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 115201, Taiwan
| | - Antonius Matzke
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 115201, Taiwan
| | - Marjori Matzke
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 115201, Taiwan
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11
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Mann CWG, Sawyer A, Gardiner DM, Mitter N, Carroll BJ, Eamens AL. RNA-Based Control of Fungal Pathogens in Plants. Int J Mol Sci 2023; 24:12391. [PMID: 37569766 PMCID: PMC10418863 DOI: 10.3390/ijms241512391] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 08/01/2023] [Accepted: 08/01/2023] [Indexed: 08/13/2023] Open
Abstract
Our duty to conserve global natural ecosystems is increasingly in conflict with our need to feed an expanding population. The use of conventional pesticides not only damages the environment and vulnerable biodiversity but can also still fail to prevent crop losses of 20-40% due to pests and pathogens. There is a growing call for more ecologically sustainable pathogen control measures. RNA-based biopesticides offer an eco-friendly alternative to the use of conventional fungicides for crop protection. The genetic modification (GM) of crops remains controversial in many countries, though expression of transgenes inducing pathogen-specific RNA interference (RNAi) has been proven effective against many agronomically important fungal pathogens. The topical application of pathogen-specific RNAi-inducing sprays is a more responsive, GM-free approach to conventional RNAi transgene-based crop protection. The specific targeting of essential pathogen genes, the development of RNAi-nanoparticle carrier spray formulations, and the possible structural modifications to the RNA molecules themselves are crucial to the success of this novel technology. Here, we outline the current understanding of gene silencing pathways in plants and fungi and summarize the pioneering and recent work exploring RNA-based biopesticides for crop protection against fungal pathogens, with a focus on spray-induced gene silencing (SIGS). Further, we discuss factors that could affect the success of RNA-based control strategies, including RNA uptake, stability, amplification, and movement within and between the plant host and pathogen, as well as the cost and design of RNA pesticides.
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Affiliation(s)
- Christopher W. G. Mann
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD 4072, Australia; (C.W.G.M.); (A.S.); (B.J.C.)
| | - Anne Sawyer
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD 4072, Australia; (C.W.G.M.); (A.S.); (B.J.C.)
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St. Lucia, QLD 4072, Australia; (D.M.G.); (N.M.)
| | - Donald M. Gardiner
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St. Lucia, QLD 4072, Australia; (D.M.G.); (N.M.)
| | - Neena Mitter
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St. Lucia, QLD 4072, Australia; (D.M.G.); (N.M.)
| | - Bernard J. Carroll
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD 4072, Australia; (C.W.G.M.); (A.S.); (B.J.C.)
| | - Andrew L. Eamens
- School of Health, University of the Sunshine Coast, Maroochydore, QLD 4558, Australia
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12
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Bélanger S, Zhan J, Meyers BC. Phylogenetic analyses of seven protein families refine the evolution of small RNA pathways in green plants. PLANT PHYSIOLOGY 2023; 192:1183-1203. [PMID: 36869858 PMCID: PMC10231463 DOI: 10.1093/plphys/kiad141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 02/14/2023] [Accepted: 02/15/2023] [Indexed: 06/01/2023]
Abstract
Several protein families participate in the biogenesis and function of small RNAs (sRNAs) in plants. Those with primary roles include Dicer-like (DCL), RNA-dependent RNA polymerase (RDR), and Argonaute (AGO) proteins. Protein families such as double-stranded RNA-binding (DRB), SERRATE (SE), and SUPPRESSION OF SILENCING 3 (SGS3) act as partners of DCL or RDR proteins. Here, we present curated annotations and phylogenetic analyses of seven sRNA pathway protein families performed on 196 species in the Viridiplantae (aka green plants) lineage. Our results suggest that the RDR3 proteins emerged earlier than RDR1/2/6. RDR6 is found in filamentous green algae and all land plants, suggesting that the evolution of RDR6 proteins coincides with the evolution of phased small interfering RNAs (siRNAs). We traced the origin of the 24-nt reproductive phased siRNA-associated DCL5 protein back to the American sweet flag (Acorus americanus), the earliest diverged, extant monocot species. Our analyses of AGOs identified multiple duplication events of AGO genes that were lost, retained, or further duplicated in subgroups, indicating that the evolution of AGOs is complex in monocots. The results also refine the evolution of several clades of AGO proteins, such as AGO4, AGO6, AGO17, and AGO18. Analyses of nuclear localization signal sequences and catalytic triads of AGO proteins shed light on the regulatory roles of diverse AGOs. Collectively, this work generates a curated and evolutionarily coherent annotation for gene families involved in plant sRNA biogenesis/function and provides insights into the evolution of major sRNA pathways.
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Affiliation(s)
| | - Junpeng Zhan
- Donald Danforth Plant Science Center, St. Louis, MO 63132, USA
| | - Blake C Meyers
- Donald Danforth Plant Science Center, St. Louis, MO 63132, USA
- Division of Plant Science and Technology, University of Missouri, Columbia, MO 65211, USA
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13
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Bazin J, Elvira-Matelot E, Blein T, Jauvion V, Bouteiller N, Cao J, Crespi MD, Vaucheret H. Synergistic action of the Arabidopsis spliceosome components PRP39a and SmD1b in promoting posttranscriptional transgene silencing. THE PLANT CELL 2023; 35:1917-1935. [PMID: 36970782 PMCID: PMC10226559 DOI: 10.1093/plcell/koad091] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 03/03/2023] [Accepted: 03/07/2023] [Indexed: 05/30/2023]
Abstract
Besides regulating splicing, the conserved spliceosome component SmD1 (Small nuclear ribonucleoprotein D1)b promotes posttranscriptional silencing of sense transgenes (S-PTGS [post-transcriptional genesilencing]). Here, we show that the conserved spliceosome component PRP39 (Pre-mRNA-processing factor 39)a also plays a role in S-PTGS in Arabidopsis thaliana. However, PRP39a and SmD1b actions appear distinct in both splicing and S-PTGS. Indeed, RNAseq-based analysis of expression level and alternative splicing in prp39a and smd1b mutants identified different sets of deregulated transcripts and noncoding RNAs. Moreover, double mutant analyses involving prp39a or smd1b and RNA quality control (RQC) mutants revealed distinct genetic interactions for SmD1b and PRP39a with nuclear RQC machineries, suggesting nonredundant roles in the RQC/PTGS interplay. Supporting this hypothesis, a prp39a smd1b double mutant exhibited enhanced suppression of S-PTGS compared to the single mutants. Because the prp39a and smd1b mutants (i) showed no major changes in the expression of PTGS or RQC components or in small RNA production and (ii) do not alter PTGS triggered by inverted-repeat transgenes directly producing dsRNA (IR-PTGS), PRP39a, and SmD1b appear to synergistically promote a step specific to S-PTGS. We propose that, independently from their specific roles in splicing, PRP39a and SmD1b limit 3'-to-5' and/or 5'-to-3' degradation of transgene-derived aberrant RNAs in the nucleus, thus favoring the export of aberrant RNAs to the cytoplasm where their conversion into double-stranded RNA (dsRNA) initiates S-PTGS.
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Affiliation(s)
- Jérémie Bazin
- Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, INRAE, Universités Paris-Sud, Evry, Paris-Diderot, Sorbonne Paris-Cité, Paris-Saclay, Bâtiment 630, 91405 Orsay, France
| | - Emilie Elvira-Matelot
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000 Versailles, France
| | - Thomas Blein
- Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, INRAE, Universités Paris-Sud, Evry, Paris-Diderot, Sorbonne Paris-Cité, Paris-Saclay, Bâtiment 630, 91405 Orsay, France
| | - Vincent Jauvion
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000 Versailles, France
| | - Nathalie Bouteiller
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000 Versailles, France
| | - Jun Cao
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, Spemannstrasse 35, 72076 Tübingen, Germany
| | - Martin D Crespi
- Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, INRAE, Universités Paris-Sud, Evry, Paris-Diderot, Sorbonne Paris-Cité, Paris-Saclay, Bâtiment 630, 91405 Orsay, France
| | - Hervé Vaucheret
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000 Versailles, France
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14
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Jeynes-Cupper K, Catoni M. Long distance signalling and epigenetic changes in crop grafting. FRONTIERS IN PLANT SCIENCE 2023; 14:1121704. [PMID: 37021313 PMCID: PMC10067726 DOI: 10.3389/fpls.2023.1121704] [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: 12/12/2022] [Accepted: 03/10/2023] [Indexed: 06/19/2023]
Abstract
Humans have used grafting for more than 4000 years to improve plant production, through physically joining two different plants, which can continue to grow as a single organism. Today, grafting is becoming increasingly more popular as a technique to increase the production of herbaceous horticultural crops, where rootstocks can introduce traits such as resistance to several pathogens and/or improving the plant vigour. Research in model plants have documented how long-distance signalling mechanisms across the graft junction, together with epigenetic regulation, can produce molecular and phenotypic changes in grafted plants. Yet, most of the studied examples rely on proof-of-concept experiments or on limited specific cases. This review explores the link between research findings in model plants and crop species. We analyse studies investigating the movement of signalling molecules across the graft junction and their implications on epigenetic regulation. The improvement of genomics analyses and the increased availability of genetic resources has allowed to collect more information on potential benefits of grafting in horticultural crop models. Ultimately, further research into this topic will enhance our ability to use the grafting technique to exploit genetic and epigenetic variation in crops, as an alternative to traditional breeding.
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Affiliation(s)
| | - Marco Catoni
- School of Biosciences, University of Birmingham, Birmingham, United Kingdom
- Institute for Sustainable Plant Protection, National Research Council of Italy, Torino, Italy
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15
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Vaucheret H. Epigenetic management of self and non-self: lessons from 40 years of transgenic plants. C R Biol 2023; 345:149-174. [PMID: 36847123 DOI: 10.5802/crbiol.96] [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: 11/04/2022] [Accepted: 11/07/2022] [Indexed: 12/02/2022]
Abstract
Plant varieties exhibiting unstable or variegated phenotypes, or showing virus recovery have long remained a mystery. It is only with the development of transgenic plants 40 years ago that the epigenetic features underlying these phenomena were elucidated. Indeed, the study of transgenic plants that did not express the introduced sequences revealed that transgene loci sometimes undergo transcriptional gene silencing (TGS) or post-transcriptional gene silencing (PTGS) by activating epigenetic defenses that naturally control transposable elements, duplicated genes or viruses. Even when they do not trigger TGS or PTGS spontaneously, stably expressed transgenes driven by viral promoters set apart from endogenous genes in their epigenetic regulation. As a result, transgenes driven by viral promoters are capable of undergoing systemic PTGS throughout the plant, whereas endogenous genes can only undergo local PTGS in cells where RNA quality control is impaired. Together, these results indicate that the host genome distinguishes self from non-self at the epigenetic level, allowing PTGS to eliminate non-self, and preventing PTGS to become systemic and kill the plant when it is locally activated against deregulated self.
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16
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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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17
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Valli AA, Gonzalo-Magro I, Sanchez DH. Rearranged Endogenized Plant Pararetroviruses as Evidence of Heritable RNA-based Immunity. Mol Biol Evol 2022; 40:6794085. [PMID: 36322467 PMCID: PMC9868043 DOI: 10.1093/molbev/msac240] [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] [Received: 01/04/2022] [Revised: 09/05/2022] [Accepted: 10/25/2022] [Indexed: 01/24/2023] Open
Abstract
Eukaryotic genomics frequently revealed historical spontaneous endogenization events of external invading nucleic acids, such as viral elements. In plants, an extensive occurrence of endogenous plant pararetroviruses (EPRVs) is usually believed to endow hosts with an additional layer of internal suppressive weaponry. However, an actual demonstration of this activity remains speculative. We analyzed the EPRV component and accompanying silencing effectors of Solanum lycopersicum, documenting that intronic/intergenic pararetroviral integrations bearing inverted-repeats fuel the plant's RNA-based immune system with suitable transcripts capable of evoking a silencing response. A surprisingly small set of rearrangements explained a substantial fraction of pararetroviral-derived endogenous small-interfering (si)RNAs, enriched in 22-nt forms typically associated with anti-viral post-transcriptional gene silencing. We provide preliminary evidence that such genetic and immunological signals may be found in other species outside the genus Solanum. Based on molecular dating, bioinformatics, and empirical explorations, we propose that homology-dependent silencing emerging from particular immuno-competent rearranged chromosomal areas that constitute an adaptive heritable trans-acting record of past infections, with potential impact against the unlocking of plant latent EPRVs and cognate-free pararetroviruses.
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Affiliation(s)
| | - Irene Gonzalo-Magro
- Centro Nacional de Biotecnología (CNB-CSIC), Calle Darwin 3, 28049 Madrid, Spain
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18
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Gouthu S, Mandelli C, Eubanks BA, Deluc LG. Transgene-free genome editing and RNAi ectopic application in fruit trees: Potential and limitations. FRONTIERS IN PLANT SCIENCE 2022; 13:979742. [PMID: 36325537 PMCID: PMC9621297 DOI: 10.3389/fpls.2022.979742] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 09/20/2022] [Indexed: 06/16/2023]
Abstract
For the past fifteen years, significant research advances in sequencing technology have led to a substantial increase in fruit tree genomic resources and databases with a massive number of OMICS datasets (transcriptomic, proteomics, metabolomics), helping to find associations between gene(s) and performance traits. Meanwhile, new technology tools have emerged for gain- and loss-of-function studies, specifically in gene silencing and developing tractable plant models for genetic transformation. Additionally, innovative and adapted transformation protocols have optimized genetic engineering in most fruit trees. The recent explosion of new gene-editing tools allows for broadening opportunities for functional studies in fruit trees. Yet, the fruit tree research community has not fully embraced these new technologies to provide large-scale genome characterizations as in cereals and other staple food crops. Instead, recent research efforts in the fruit trees appear to focus on two primary translational tools: transgene-free gene editing via Ribonucleoprotein (RNP) delivery and the ectopic application of RNA-based products in the field for crop protection. The inherent nature of the propagation system and the long juvenile phase of most fruit trees are significant justifications for the first technology. The second approach might have the public favor regarding sustainability and an eco-friendlier environment for a crop production system that could potentially replace the use of chemicals. Regardless of their potential, both technologies still depend on the foundational knowledge of gene-to-trait relationships generated from basic genetic studies. Therefore, we will discuss the status of gene silencing and DNA-based gene editing techniques for functional studies in fruit trees followed by the potential and limitations of their translational tools (RNP delivery and RNA-based products) in the context of crop production.
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Affiliation(s)
- Satyanarayana Gouthu
- Department of Horticulture, Oregon State University, Corvallis, OR, United States
| | - Christian Mandelli
- Oregon Wine Research Institute, Oregon State University, Corvallis, OR, United States
| | - Britt A. Eubanks
- Department of Horticulture, Oregon State University, Corvallis, OR, United States
| | - Laurent G. Deluc
- Department of Horticulture, Oregon State University, Corvallis, OR, United States
- Oregon Wine Research Institute, Oregon State University, Corvallis, OR, United States
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19
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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: 12] [Impact Index Per Article: 6.0] [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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20
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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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21
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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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22
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Yan Y, Ham BK. The Mobile Small RNAs: Important Messengers for Long-Distance Communication in Plants. FRONTIERS IN PLANT SCIENCE 2022; 13:928729. [PMID: 35783973 PMCID: PMC9247610 DOI: 10.3389/fpls.2022.928729] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 05/25/2022] [Indexed: 06/06/2023]
Abstract
Various species of small RNAs (sRNAs), notably microRNAs and small interfering RNAs (siRNAs), have been characterized as the major effectors of RNA interference in plants. Growing evidence supports a model in which sRNAs move, intercellularly, systemically, and between cross-species. These non-coding sRNAs can traffic cell-to-cell through plasmodesmata (PD), in a symplasmic manner, as well as from source to sink tissues, via the phloem, to trigger gene silencing in their target cells. Such mobile sRNAs function in non-cell-autonomous communication pathways, to regulate various biological processes, such as plant development, reproduction, and plant defense. In this review, we summarize recent progress supporting the roles of mobile sRNA in plants, and discuss mechanisms of sRNA transport, signal amplification, and the plant's response, in terms of RNAi activity, within the recipient tissues. We also discuss potential research directions and their likely impact on engineering of crops with traits for achieving food security.
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Affiliation(s)
- Yan Yan
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, United States
| | - Byung-Kook Ham
- Global Institute for Food Security, University of Saskatchewan, Saskatoon, SK, Canada
- Department of Biology, University of Saskatchewan, Saskatoon, SK, Canada
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23
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Cuerda-Gil D, Hung YH, Panda K, Slotkin RK. A plant tethering system for the functional study of protein-RNA interactions in vivo. PLANT METHODS 2022; 18:75. [PMID: 35658900 PMCID: PMC9166424 DOI: 10.1186/s13007-022-00907-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 05/11/2022] [Indexed: 06/15/2023]
Abstract
The sorting of RNA transcripts dictates their ultimate post-transcriptional fates, such as translation, decay or degradation by RNA interference (RNAi). This sorting of RNAs into distinct fates is mediated by their interaction with RNA-binding proteins. While hundreds of RNA binding proteins have been identified, which act to sort RNAs into different pathways is largely unknown. Particularly in plants, this is due to the lack of reliable protein-RNA artificial tethering tools necessary to determine the mechanism of protein action on an RNA in vivo. Here we generated a protein-RNA tethering system which functions on an endogenous Arabidopsis RNA that is tracked by the quantitative flowering time phenotype. Unlike other protein-RNA tethering systems that have been attempted in plants, our system circumvents the inadvertent triggering of RNAi. We successfully in vivo tethered a protein epitope, deadenylase protein and translation factor to the target RNA, which function to tag, decay and boost protein production, respectively. We demonstrated that our tethering system (1) is sufficient to engineer the downstream fate of an RNA, (2) enables the determination of any protein's function upon recruitment to an RNA, and (3) can be used to discover new interactions with RNA-binding proteins.
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Affiliation(s)
- Diego Cuerda-Gil
- Donald Danforth Plant Science Center, St. Louis, MO, USA
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, USA
| | - Yu-Hung Hung
- Donald Danforth Plant Science Center, St. Louis, MO, USA
| | - Kaushik Panda
- Donald Danforth Plant Science Center, St. Louis, MO, USA
| | - R Keith Slotkin
- Donald Danforth Plant Science Center, St. Louis, MO, USA.
- Division of Biological Sciences, University of Missouri, Columbia, MO, USA.
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24
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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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25
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Rössner C, Lotz D, Becker A. VIGS Goes Viral: How VIGS Transforms Our Understanding of Plant Science. ANNUAL REVIEW OF PLANT BIOLOGY 2022; 73:703-728. [PMID: 35138878 DOI: 10.1146/annurev-arplant-102820-020542] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Virus-induced gene silencing (VIGS) has developed into an indispensable approach to gene function analysis in a wide array of species, many of which are not amenable to stable genetic transformation. VIGS utilizes the posttranscriptional gene silencing (PTGS) machinery of plants to restrain viral infections systemically and is used to downregulate the plant's endogenous genes. Here, we review the molecular mechanisms of DNA- and RNA-virus-based VIGS, its inherent connection to PTGS, and what is known about the systemic spread of silencing. Recently, VIGS-based technologies have been expanded to enable not only gene silencing but also overexpression [virus-induced overexpression (VOX)], genome editing [virus-induced genome editing (VIGE)], and host-induced gene silencing (HIGS). These techniques expand the genetic toolbox for nonmodel organisms even more. Further, we illustrate the versatility of VIGS and the methods derived from it in elucidating molecular mechanisms, using tomato fruit ripening and programmed cell death as examples. Finally, we discuss challenges of and future perspectives on the use of VIGS to advance gene function analysis in nonmodel plants in the postgenomic era.
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Affiliation(s)
- Clemens Rössner
- Institute of Botany, Justus-Liebig University Gießen, Gießen, Germany;
| | - Dominik Lotz
- Institute of Botany, Justus-Liebig University Gießen, Gießen, Germany;
| | - Annette Becker
- Institute of Botany, Justus-Liebig University Gießen, Gießen, Germany;
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26
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Liu F, Chern M, Jain R, Martin JA, Schakwitz WS, Ronald PC. Silencing of Dicer-like protein 2a restores the resistance phenotype in the rice mutant, sxi4 (suppressor of Xa21-mediated immunity 4). THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 110:646-657. [PMID: 35106860 DOI: 10.1111/tpj.15692] [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: 09/22/2020] [Revised: 01/23/2022] [Accepted: 01/25/2022] [Indexed: 06/14/2023]
Abstract
The rice immune receptor XA21 confers resistance to Xanthomonas oryzae pv. oryzae (Xoo), and upon recognition of the RaxX21-sY peptide produced by Xoo, XA21 activates the plant immune response. Here we screened 21 000 mutant plants expressing XA21 to identify components involved in this response, and reported here the identification of a rice mutant, sxi4, which is susceptible to Xoo. The sxi4 mutant carries a 32-kb translocation from chromosome 3 onto chromosome 7 and displays an elevated level of DCL2a transcript, encoding a Dicer-like protein. Silencing of DCL2a in the sxi4 genetic background restores resistance to Xoo. RaxX21-sY peptide-treated leaves of sxi4 retain the hallmarks of XA21-mediated immune response. However, WRKY45-1, a known negative regulator of rice resistance to Xoo, is induced in the sxi4 mutant in response to RaxX21-sY peptide treatment. A CRISPR knockout of a short interfering RNA (TE-siRNA815) in the intron of WRKY45-1 restores the resistance phenotype in sxi4. These results suggest a model where DCL2a accumulation negatively regulates XA21-mediated immunity by altering the processing of TE-siRNA815.
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Affiliation(s)
- Furong Liu
- Department of Plant Pathology and Genome Center, University of California, Davis, CA, 95616, USA
| | - Mawsheng Chern
- Department of Plant Pathology and Genome Center, University of California, Davis, CA, 95616, USA
| | - Rashmi Jain
- Department of Plant Pathology and Genome Center, University of California, Davis, CA, 95616, USA
| | - Joel A Martin
- Department of Energy Joint Genome Institute, Berkeley, CA, 94720, USA
| | - Wendy S Schakwitz
- Department of Energy Joint Genome Institute, Berkeley, CA, 94720, USA
| | - Pamela C Ronald
- Department of Plant Pathology and Genome Center, University of California, Davis, CA, 95616, USA
- Feedstocks Division, The Joint Bioenergy Institute, Emeryville, CA, 94608, USA
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27
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Chen X, Rechavi O. Plant and animal small RNA communications between cells and organisms. Nat Rev Mol Cell Biol 2022; 23:185-203. [PMID: 34707241 PMCID: PMC9208737 DOI: 10.1038/s41580-021-00425-y] [Citation(s) in RCA: 71] [Impact Index Per Article: 35.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/24/2021] [Indexed: 01/09/2023]
Abstract
Since the discovery of eukaryotic small RNAs as the main effectors of RNA interference in the late 1990s, diverse types of endogenous small RNAs have been characterized, most notably microRNAs, small interfering RNAs (siRNAs) and PIWI-interacting RNAs (piRNAs). These small RNAs associate with Argonaute proteins and, through sequence-specific gene regulation, affect almost every major biological process. Intriguing features of small RNAs, such as their mechanisms of amplification, rapid evolution and non-cell-autonomous function, bestow upon them the capacity to function as agents of intercellular communications in development, reproduction and immunity, and even in transgenerational inheritance. Although there are many types of extracellular small RNAs, and despite decades of research, the capacity of these molecules to transmit signals between cells and between organisms is still highly controversial. In this Review, we discuss evidence from different plants and animals that small RNAs can act in a non-cell-autonomous manner and even exchange information between species. We also discuss mechanistic insights into small RNA communications, such as the nature of the mobile agents, small RNA signal amplification during transit, signal perception and small RNA activity at the destination.
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Affiliation(s)
- Xuemei Chen
- Department of Botany and Plant Sciences, Institute for Integrative Genome Biology, University of California, Riverside, CA, USA.
| | - Oded Rechavi
- Department of Neurobiology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel. .,Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel.
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28
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Ren Y, Li M, Wang W, Lan W, Schenke D, Cai D, Miao Y. MicroRNA840 (MIR840) accelerates leaf senescence by targeting the overlapping 3'UTRs of PPR and WHIRLY3 in Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 109:126-143. [PMID: 34724261 DOI: 10.1111/tpj.15559] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 10/13/2021] [Accepted: 10/25/2021] [Indexed: 06/13/2023]
Abstract
MicroRNAs negatively regulate gene expression by promoting target mRNA cleavage and/or impairing its translation, thereby playing a crucial role in plant development and environmental stress responses. In Arabidopsis, the MIR840 gene is located within the overlapping 3'UTR of the PPR and WHIRLY3 (WHY3) genes, both being predicted targets of miR840* and miR840, the short maturation products of MIR840. Gain- and loss-of-function of MIR840 in Arabidopsis resulted in opposite senescence phenotypes. The highest expression levels of the MIR840 precursor transcript pre-miR840 were observed at senescence initiation, and pre-miR840 expression is significantly correlated with a reduction in PPR, but not WHY3, transcript levels. Although a reduction of transcript level of PPR, but not WHY3 transcript levels were not significantly affected by MIR840 overexpression, its protein levels were strongly reduced. Mutating the cleavage sites or replacing the target sequences abolishes the miR840*/miR840-mediated degradation of PPR transcripts and accumulation of WHY3 protein. In support for this, concurrent knockdown of both PPR and WHY3 in wild-type plants resulted in a senescence phenotype resembling that of the MIR840-overexpressing plant. This indicates that both PRR and WHY3 are targets in the MIR840-mediated senescence pathway. Moreover, single knockout mutants of PPR and WHY3 show a convergent upregulated subset of senescence-associated genes, which are also found among those induced by MIR840 overexpression. Our data provide evidence for a regulatory role of MIR840 in plant senescence.
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Affiliation(s)
- Yujun Ren
- Fujian Provincial Key Laboratory of Plant Functional Biology, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Mengsi Li
- Fujian Provincial Key Laboratory of Plant Functional Biology, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Wanzhen Wang
- Fujian Provincial Key Laboratory of Plant Functional Biology, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Wei Lan
- Fujian Provincial Key Laboratory of Plant Functional Biology, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Dirk Schenke
- Department of Molecular Phytopathology, Christian-Albrechts University of Kiel, Kiel, Germany
| | - Daguang Cai
- Department of Molecular Phytopathology, Christian-Albrechts University of Kiel, Kiel, Germany
| | - Ying Miao
- Fujian Provincial Key Laboratory of Plant Functional Biology, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
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29
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Fei Y, Pyott DE, Molnar A. Temperature modulates virus-induced transcriptional gene silencing via secondary small RNAs. THE NEW PHYTOLOGIST 2021; 232:356-371. [PMID: 34185326 DOI: 10.1111/nph.17586] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 06/17/2021] [Indexed: 05/08/2023]
Abstract
Virus-induced gene silencing (VIGS) can be harnessed to sequence-specifically degrade host transcripts and induce heritable epigenetic modifications referred to as virus-induced post-transcriptional gene silencing (ViPTGS) and virus-induced transcriptional gene silencing (ViTGS), respectively. Both ViPTGS and ViTGS enable manipulation of endogenous gene expression without the need for transgenesis. Although VIGS has been widely used in many plant species, it is not always uniform or highly efficient. The efficiency of VIGS is affected by developmental, physiological and environmental factors. Here, we use recombinant Tobacco rattle viruses (TRV) to study the effect of temperature on ViPTGS and ViTGS using GFP as a reporter gene of silencing in N. benthamiana 16c plants. We found that unlike ViPTGS, ViTGS was impaired at high temperature. Using a novel mismatch-small interfering RNA (siRNA) tool, which precisely distinguishes virus-derived (primary) from target-generated (secondary) siRNAs, we demonstrated that the lack of secondary siRNA production/amplification was responsible for inefficient ViTGS at 29°C. Moreover, inefficient ViTGS at 29°C inhibited the transmission of epigenetic gene silencing to the subsequent generations. Our finding contributes to understanding the impact of environmental conditions on primary and secondary siRNA production and may pave the way to design/optimize ViTGS for transgene-free crop improvement.
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Affiliation(s)
- Yue Fei
- Institute of Molecular Plant Sciences, University of Edinburgh, Max Born Crescent, Edinburgh, EH9 3BF, UK
| | - Douglas E Pyott
- Institute of Molecular Plant Sciences, University of Edinburgh, Max Born Crescent, Edinburgh, EH9 3BF, UK
| | - Attila Molnar
- Institute of Molecular Plant Sciences, University of Edinburgh, Max Born Crescent, Edinburgh, EH9 3BF, UK
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30
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Leonetti P, Stuttmann J, Pantaleo V. Regulation of plant antiviral defense genes via host RNA-silencing mechanisms. Virol J 2021; 18:194. [PMID: 34565394 PMCID: PMC8474839 DOI: 10.1186/s12985-021-01664-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 09/14/2021] [Indexed: 12/23/2022] Open
Abstract
Background Plants in nature or crops in the field interact with a multitude of beneficial or parasitic organisms, including bacteria, fungi and viruses. Viruses are highly specialized to infect a limited range of host plants, leading in extreme cases to the full invasion of the host and a diseased phenotype. Resistance to viruses can be mediated by various passive or active mechanisms, including the RNA-silencing machinery and the innate immune system. Main text RNA-silencing mechanisms may inhibit viral replication, while viral components can elicit the innate immune system. Viruses that successfully enter the plant cell can elicit pattern-triggered immunity (PTI), albeit by yet unknown mechanisms. As a counter defense, viruses suppress PTI. Furthermore, viral Avirulence proteins (Avr) may be detected by intracellular immune receptors (Resistance proteins) to elicit effector-triggered immunity (ETI). ETI often culminates in a localized programmed cell death reaction, the hypersensitive response (HR), and is accompanied by a potent systemic defense response. In a dichotomous view, RNA silencing and innate immunity are seen as two separate mechanisms of resistance. Here, we review the intricate connections and similarities between these two regulatory systems, which are collectively required to ensure plant fitness and resilience. Conclusions The detailed understanding of immune regulation at the transcriptional level provides novel opportunities for enhancing plant resistance to viruses by RNA-based technologies. However, extensive use of RNA technologies requires a thorough understanding of the molecular mechanisms of RNA gene regulation. We describe the main examples of host RNA-mediated regulation of virus resistance.
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Affiliation(s)
- Paola Leonetti
- Department of Biology, Agricultural and Food Sciences, Institute for Sustainable Plant Protection, Research Unit of Bari, CNR, 70126, Bari, Italy
| | - Johannes Stuttmann
- Institute of Biology, Department of Plant Genetics, Martin Luther University, Halle-Wittenberg, 06120, Halle (Saale), Germany
| | - Vitantonio Pantaleo
- Department of Biology, Agricultural and Food Sciences, Institute for Sustainable Plant Protection, Research Unit of Bari, CNR, 70126, Bari, Italy. .,Institute of Biochemistry and Biotechnology, Martin Luther University, Halle-Wittenberg, 06120, Halle (Saale), Germany.
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31
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Hendrix B, Zheng W, Bauer MJ, Havecker ER, Mai JT, Hoffer PH, Sanders RA, Eads BD, Caruano-Yzermans A, Taylor DN, Hresko C, Oakes J, Iandolino AB, Bennett MJ, Deikman J. Topically delivered 22 nt siRNAs enhance RNAi silencing of endogenous genes in two species. PLANTA 2021; 254:60. [PMID: 34448043 PMCID: PMC8390415 DOI: 10.1007/s00425-021-03708-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Accepted: 08/16/2021] [Indexed: 05/23/2023]
Abstract
MAIN CONCLUSION 22 nt siRNAs applied to leaves induce production of transitive sRNAs for targeted genes and can enhance local silencing. Systemic silencing was only observed for a GFP transgene. RNA interference (RNAi) is a gene silencing mechanism important in regulating gene expression during plant development, response to the environment and defense. Better understanding of the molecular mechanisms of this pathway may lead to future strategies to improve crop traits of value. An abrasion method to deliver siRNAs into leaf cells of intact plants was used to investigate the activities of 21 and 22 nt siRNAs in silencing genes in Nicotiana benthamiana and Amaranthus cruentus. We confirmed that both 21 and 22 nt siRNAs were able to silence a green fluorescent protein (GFP) transgene in treated leaves of N. benthamiana, but systemic silencing of GFP occurred only when the guide strand contained 22 nt. Silencing in the treated leaves of N. benthamiana was demonstrated for three endogenous genes: magnesium cheletase subunit I (CHL-I), magnesium cheletase subunit H (CHL-H), and GENOMES UNCOUPLED4 (GUN4). However, systemic silencing of these endogenous genes was not observed. Very high levels of transitive siRNAs were produced for GFP in response to treatment with 22 nt siRNAs but only low levels were produced in response to a 21 nt siRNA. The endogenous genes tested also produced transitive siRNAs in response to 22 nt siRNAs. 22 nt siRNAs produced greater local silencing phenotypes than 21 nt siRNAs for three of the genes. These special properties of 22 nt siRNAs were also observed for the CHL-H gene in A. cruentus. These experiments suggest a functional role for transitive siRNAs in amplifying the RNAi response.
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Affiliation(s)
- Bill Hendrix
- Bayer Crop Science, 37437 State Highway 16, Woodland, CA, 95695, USA
- Bayer U.S. LLC, Research and Development, Crop Science, Biologics Pest Control, 890 Embarcadero Drive, West Sacramento, CA, 95605, USA
| | - Wei Zheng
- Bayer Crop Science, 37437 State Highway 16, Woodland, CA, 95695, USA
| | - Matthew J Bauer
- Bayer Crop Science, 700 Chesterfield Parkway West, Chesterfield, MO, 63017, USA
| | - Ericka R Havecker
- Bayer Crop Science, 700 Chesterfield Parkway West, Chesterfield, MO, 63017, USA
| | - Jennifer T Mai
- Bayer Crop Science, 37437 State Highway 16, Woodland, CA, 95695, USA
| | - Paul H Hoffer
- Bayer Crop Science, 37437 State Highway 16, Woodland, CA, 95695, USA
- California Governor's Office of Emergency Services, 3650 Schriever Avenue, Mather, CA, 95655, USA
| | - Rick A Sanders
- Bayer Crop Science, 37437 State Highway 16, Woodland, CA, 95695, USA
| | - Brian D Eads
- Bayer Crop Science, 700 Chesterfield Parkway West, Chesterfield, MO, 63017, USA
| | | | - Danielle N Taylor
- Bayer Crop Science, 700 Chesterfield Parkway West, Chesterfield, MO, 63017, USA
| | - Chelly Hresko
- Bayer Crop Science, 700 Chesterfield Parkway West, Chesterfield, MO, 63017, USA
| | - Janette Oakes
- Bayer Crop Science, 37437 State Highway 16, Woodland, CA, 95695, USA
| | | | - Michael J Bennett
- Bayer Crop Science, 37437 State Highway 16, Woodland, CA, 95695, USA
| | - Jill Deikman
- Bayer Crop Science, 37437 State Highway 16, Woodland, CA, 95695, USA.
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32
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The diversity of post-transcriptional gene silencing mediated by small silencing RNAs in plants. Essays Biochem 2021; 64:919-930. [PMID: 32885814 DOI: 10.1042/ebc20200006] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Revised: 08/11/2020] [Accepted: 08/14/2020] [Indexed: 12/31/2022]
Abstract
In plants, post-transcriptional gene silencing (PTGS) tightly regulates development, maintains genome stability and protects plant against foreign genes. PTGS can be triggered by virus infection, transgene, and endogenous transcript, thus commonly serves as an RNA-based immune mechanism. Accordingly, based on the initiating factors, PTGS can be divided into viral-PTGS, transgene-PTGS, and endo-gene-PTGS. Unlike the intensely expressed invading transgenes and viral genes that frequently undergo PTGS, most endogenous genes do not trigger PTGS, except for a few that can produce endogenous small RNAs (sRNAs), including microRNA (miRNA) and small interfering RNA (siRNA). Different lengths of miRNA and siRNA, mainly 21-, 22- or 24-nucleotides (nt) exert diverse functions, ranging from target mRNA degradation, translational inhibition, or DNA methylation and chromatin modifications. The abundant 21-nt miRNA or siRNA, processed by RNase-III enzyme DICER-LIKE 1 (DCL1) and DCL4, respectively, have been well studied in the PTGS pathways. By contrast, the scarceness of endogenous 22-nt sRNAs that are primarily processed by DCL2 limits their research, although a few encouraging studies have been reported recently. Therefore, we review here our current understanding of diverse PTGS pathways triggered by a variety of sRNAs and summarize the distinct features of the 22-nt sRNA mediated PTGS.
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33
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Butel N, Yu A, Le Masson I, Borges F, Elmayan T, Taochy C, Gursanscky NR, Cao J, Bi S, Sawyer A, Carroll BJ, Vaucheret H. Contrasting epigenetic control of transgenes and endogenous genes promotes post-transcriptional transgene silencing in Arabidopsis. Nat Commun 2021; 12:2787. [PMID: 33986281 PMCID: PMC8119426 DOI: 10.1038/s41467-021-22995-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 04/06/2021] [Indexed: 11/20/2022] Open
Abstract
Transgenes that are stably expressed in plant genomes over many generations could be assumed to behave epigenetically the same as endogenous genes. Here, we report that whereas the histone H3K9me2 demethylase IBM1, but not the histone H3K4me3 demethylase JMJ14, counteracts DNA methylation of Arabidopsis endogenous genes, JMJ14, but not IBM1, counteracts DNA methylation of expressed transgenes. Additionally, JMJ14-mediated specific attenuation of transgene DNA methylation enhances the production of aberrant RNAs that readily induce systemic post-transcriptional transgene silencing (PTGS). Thus, the JMJ14 chromatin modifying complex maintains expressed transgenes in a probationary state of susceptibility to PTGS, suggesting that the host plant genome does not immediately accept expressed transgenes as being epigenetically the same as endogenous genes. Accumulating evidences point to a discrepancy in the epigenetic behaviour of transgenes and endogenous genes. Here, via characterization of mutants impaired in histone demethylases JMJ14 and IBM1, the authors show that transgenes and endogenous genes are regulated by different epigenetic mechanisms in Arabidopsis.
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Affiliation(s)
- Nicolas Butel
- Institut Jean-Pierre Bourgin, UMR 1318, INRAE, AgroParisTech, Université Paris-Saclay, Versailles, France.,Université Paris-Sud, Université Paris-Saclay, Orsay, France
| | - Agnès Yu
- Institut Jean-Pierre Bourgin, UMR 1318, INRAE, AgroParisTech, Université Paris-Saclay, Versailles, France
| | - Ivan Le Masson
- Institut Jean-Pierre Bourgin, UMR 1318, INRAE, AgroParisTech, Université Paris-Saclay, Versailles, France
| | - Filipe Borges
- Institut Jean-Pierre Bourgin, UMR 1318, INRAE, AgroParisTech, Université Paris-Saclay, Versailles, France
| | - Taline Elmayan
- Institut Jean-Pierre Bourgin, UMR 1318, INRAE, AgroParisTech, Université Paris-Saclay, Versailles, France
| | - Christelle Taochy
- Institut Jean-Pierre Bourgin, UMR 1318, INRAE, AgroParisTech, Université Paris-Saclay, Versailles, France.,School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
| | - Nial R Gursanscky
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
| | - Jiangling Cao
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
| | - Shengnan Bi
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
| | - Anne Sawyer
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia.,Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, Brisbane, QLD, Australia
| | - Bernard J Carroll
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia.
| | - Hervé Vaucheret
- Institut Jean-Pierre Bourgin, UMR 1318, INRAE, AgroParisTech, Université Paris-Saclay, Versailles, France.
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Topical Application of Escherichia coli-Encapsulated dsRNA Induces Resistance in Nicotiana benthamiana to Potato Viruses and Involves RDR6 and Combined Activities of DCL2 and DCL4. PLANTS 2021; 10:plants10040644. [PMID: 33805277 PMCID: PMC8067229 DOI: 10.3390/plants10040644] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 03/24/2021] [Accepted: 03/25/2021] [Indexed: 12/18/2022]
Abstract
Exogenous application of double-stranded RNAs (dsRNAs) for inducing virus resistance in plants represents an attractive alternative to transgene-based silencing approaches. However, improvement of dsRNA stability in natural conditions is required in order to provide long-term protection against the targeted virus. Here, we tested the protective effect of topical application of Escherichia coli-encapsulated dsRNA compared to naked dsRNA against single and dual infection by Potato virus X expressing the green fluorescent protein (PVX-GFP) and Potato virus Y (PVY) in Nicotiana benthamiana. We found that, in our conditions, the effectiveness of E. coli-encapsulated dsRNA in providing RNAi-mediated protection did not differ from that of naked dsRNA. dsRNA vaccination was partly effective against a dual infection by PVX-GFP and PVY, manifested by a delay in the expression of the synergistic symptoms at early times after inoculation. Using PVX-GFP as a reporter virus together with a suite of RNAi knockdown transgenic lines, we have also shown that RNA-directed RNA polymerase 6 and the combined activities of DICER-like 2 (DCL2) and DCL4 act to promote efficient resistance to virus infection conferred by topical application of dsRNA in N. benthamiana. Our results provide evidence that exogenous dsRNA molecules are processed by the RNA silencing pathways commonly used by the host in response to virus infection.
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Hendrix B, Hoffer P, Sanders R, Schwartz S, Zheng W, Eads B, Taylor D, Deikman J. Systemic GFP silencing is associated with high transgene expression in Nicotiana benthamiana. PLoS One 2021; 16:e0245422. [PMID: 33720987 PMCID: PMC7959375 DOI: 10.1371/journal.pone.0245422] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 02/21/2021] [Indexed: 12/28/2022] Open
Abstract
Gene silencing in plants using topical dsRNA is a new approach that has the potential to be a sustainable component of the agricultural production systems of the future. However, more research is needed to enable this technology as an economical and efficacious supplement to current crop protection practices. Systemic gene silencing is one key enabling aspect. The objective of this research was to better understand topically-induced, systemic transgene silencing in Nicotiana benthamiana. A previous report details sequencing of the integration site of the Green Fluorescent Protein (GFP) transgene in the well-known N. benthamiana GFP16C event. This investigation revealed an inadvertent co-integration of part of a bacterial transposase in this line. To determine the effect of this transgene configuration on systemic silencing, new GFP transgenic lines with or without the transposase sequences were produced. GFP expression levels in the 19 single-copy events and three hemizygous GFP16C lines produced for this study ranged from 50-72% of the homozygous GFP16C line. GFP expression was equivalent to GFP16C in a two-copy event. Local GFP silencing was observed in all transgenic and GFP16C hemizygous lines after topical application of carbon dot-based formulations containing a GFP targeting dsRNA. The GFP16C-like systemic silencing phenotype was only observed in the two-copy line. The partial transposase had no impact on transgene expression level, local GFP silencing, small RNA abundance and distribution, or systemic GFP silencing in the transgenic lines. We conclude that high transgene expression level is a key enabler of topically-induced, systemic transgene silencing in N. benthamiana.
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Affiliation(s)
- Bill Hendrix
- Bayer Crop Science, Woodland, California, United States of America
| | - Paul Hoffer
- Bayer Crop Science, Woodland, California, United States of America
| | - Rick Sanders
- Bayer Crop Science, Woodland, California, United States of America
| | - Steve Schwartz
- Bayer Crop Science, Woodland, California, United States of America
| | - Wei Zheng
- Bayer Crop Science, Woodland, California, United States of America
| | - Brian Eads
- Bayer Crop Science, Chesterfield Parkway, St. Louis, Missouri, United States of America
| | - Danielle Taylor
- Bayer Crop Science, Chesterfield Parkway, St. Louis, Missouri, United States of America
| | - Jill Deikman
- Bayer Crop Science, Woodland, California, United States of America
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Sanan-Mishra N, Abdul Kader Jailani A, Mandal B, Mukherjee SK. Secondary siRNAs in Plants: Biosynthesis, Various Functions, and Applications in Virology. FRONTIERS IN PLANT SCIENCE 2021; 12:610283. [PMID: 33737942 PMCID: PMC7960677 DOI: 10.3389/fpls.2021.610283] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 01/18/2021] [Indexed: 05/13/2023]
Abstract
The major components of RNA silencing include both transitive and systemic small RNAs, which are technically called secondary sRNAs. Double-stranded RNAs trigger systemic silencing pathways to negatively regulate gene expression. The secondary siRNAs generated as a result of transitive silencing also play a substantial role in gene silencing especially in antiviral defense. In this review, we first describe the discovery and pathways of transitivity with emphasis on RNA-dependent RNA polymerases followed by description on the short range and systemic spread of silencing. We also provide an in-depth view on the various size classes of secondary siRNAs and their different roles in RNA silencing including their categorization based on their biogenesis. The other regulatory roles of secondary siRNAs in transgene silencing, virus-induced gene silencing, transitivity, and trans-species transfer have also been detailed. The possible implications and applications of systemic silencing and the different gene silencing tools developed are also described. The details on mobility and roles of secondary siRNAs derived from viral genome in plant defense against the respective viruses are presented. This entails the description of other compatible plant-virus interactions and the corresponding small RNAs that determine recovery from disease symptoms, exclusion of viruses from shoot meristems, and natural resistance. The last section presents an overview on the usefulness of RNA silencing for management of viral infections in crop plants.
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Affiliation(s)
- Neeti Sanan-Mishra
- Plant RNAi Biology Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - A. Abdul Kader Jailani
- Plant RNAi Biology Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
- Advanced Center for Plant Virology, Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi, India
| | - Bikash Mandal
- Advanced Center for Plant Virology, Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi, India
| | - Sunil K. Mukherjee
- Advanced Center for Plant Virology, Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi, India
- *Correspondence: Sunil K. Mukherjee,
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Jia J, Ji R, Li Z, Yu Y, Nakano M, Long Y, Feng L, Qin C, Lu D, Zhan J, Xia R, Meyers BC, Liu B, Zhai J. Soybean DICER-LIKE2 Regulates Seed Coat Color via Production of Primary 22-Nucleotide Small Interfering RNAs from Long Inverted Repeats. THE PLANT CELL 2020; 32:3662-3673. [PMID: 33077493 PMCID: PMC7721327 DOI: 10.1105/tpc.20.00562] [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: 07/16/2020] [Revised: 09/16/2020] [Accepted: 10/15/2020] [Indexed: 05/02/2023]
Abstract
In plants, 22-nucleotide small RNAs trigger the production of secondary small interfering RNAs (siRNAs) and enhance silencing. DICER-LIKE2 (DCL2)-dependent 22-nucleotide siRNAs are rare in Arabidopsis (Arabidopsis thaliana) and are thought to function mainly during viral infection; by contrast, these siRNAs are abundant in many crops such as soybean (Glycine max) and maize (Zea mays). Here, we studied soybean 22-nucleotide siRNAs by applying CRISPR-Cas9 to simultaneously knock out the two copies of soybean DCL2, GmDCL2a and GmDCL2b, in the Tianlong1 cultivar. Small RNA sequencing revealed that most 22-nucleotide siRNAs are derived from long inverted repeats (LIRs) and disappeared in the Gmdcl2a/2b double mutant. De novo assembly of a Tianlong1 reference genome and transcriptome profiling identified an intronic LIR formed by the chalcone synthase (CHS) genes CHS1 and CHS3 This LIR is the source of primary 22-nucleotide siRNAs that target other CHS genes and trigger the production of secondary 21-nucleotide siRNAs. Disruption of this process in Gmdcl2a/2b mutants substantially increased CHS mRNA levels in the seed coat, thus changing the coat color from yellow to brown. Our results demonstrated that endogenous LIR-derived transcripts in soybean are predominantly processed by GmDCL2 into 22-nucleotide siRNAs and uncovered a role for DCL2 in regulating natural traits.
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Affiliation(s)
- Jinbu Jia
- Department of Biology, Southern University of Science and Technology, Shenzhen 518055, China
- Institute of Plant and Food Science, Southern University of Science and Technology, Shenzhen 518055, China
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Southern University of Science and Technology, Shenzhen 518055, China
| | - Ronghuan Ji
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Zhuowen Li
- Department of Biology, Southern University of Science and Technology, Shenzhen 518055, China
- Institute of Plant and Food Science, Southern University of Science and Technology, Shenzhen 518055, China
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Southern University of Science and Technology, Shenzhen 518055, China
| | - Yiming Yu
- Department of Biology, Southern University of Science and Technology, Shenzhen 518055, China
- Institute of Plant and Food Science, Southern University of Science and Technology, Shenzhen 518055, China
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Southern University of Science and Technology, Shenzhen 518055, China
| | - Mayumi Nakano
- Donald Danforth Plant Science Center, St. Louis, Missouri 63132
| | - Yanping Long
- Department of Biology, Southern University of Science and Technology, Shenzhen 518055, China
- Institute of Plant and Food Science, Southern University of Science and Technology, Shenzhen 518055, China
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Southern University of Science and Technology, Shenzhen 518055, China
| | - Li Feng
- Department of Biology, Southern University of Science and Technology, Shenzhen 518055, China
- Institute of Plant and Food Science, Southern University of Science and Technology, Shenzhen 518055, China
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Southern University of Science and Technology, Shenzhen 518055, China
| | - Chao Qin
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Dongdong Lu
- Department of Biology, Southern University of Science and Technology, Shenzhen 518055, China
- Institute of Plant and Food Science, Southern University of Science and Technology, Shenzhen 518055, China
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Southern University of Science and Technology, Shenzhen 518055, China
| | - Junpeng Zhan
- Department of Biology, Southern University of Science and Technology, Shenzhen 518055, China
- Institute of Plant and Food Science, Southern University of Science and Technology, Shenzhen 518055, China
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Southern University of Science and Technology, Shenzhen 518055, China
- Donald Danforth Plant Science Center, St. Louis, Missouri 63132
| | - Rui Xia
- College of Horticulture, South China Agricultural University, Guangzhou 510642, China
| | - Blake C Meyers
- Donald Danforth Plant Science Center, St. Louis, Missouri 63132
- Division of Plant Sciences, University of Missouri, Columbia, Missouri 65211
| | - Bin Liu
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Jixian Zhai
- Department of Biology, Southern University of Science and Technology, Shenzhen 518055, China
- Institute of Plant and Food Science, Southern University of Science and Technology, Shenzhen 518055, China
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Southern University of Science and Technology, Shenzhen 518055, China
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Čermák V, Tyč D, Přibylová A, Fischer L. Unexpected variations in posttranscriptional gene silencing induced by differentially produced dsRNAs in tobacco cells. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2020; 1863:194647. [PMID: 33127485 DOI: 10.1016/j.bbagrm.2020.194647] [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: 04/22/2020] [Revised: 10/15/2020] [Accepted: 10/19/2020] [Indexed: 11/17/2022]
Abstract
In plants, posttranscriptional gene silencing (PTGS) is induced by small RNAs (sRNAs) generated from various dsRNA precursors. To assess the impact of dsRNA origin, we compared downregulation of GFP expression triggered by inverted repeat (IR), antisense (AS) and unterminated sense (UT) transcripts transiently expressed from the estradiol-inducible promoter. The use of homogeneously responding tobacco BY-2 cell lines allowed monitoring the onset of silencing and its reversibility. In this system, IR induced the strongest and fastest silencing accompanied by dense DNA methylation. At low induction, silencing in individual cells was binary (either strong or missing), suggesting that a certain threshold sRNA level had to be exceeded. The AS variant specifically showed a deviated sRNA-strand ratio shifted in favor of antisense orientation. In AS lines and weakly induced IR lines, only the silencer DNA was methylated, but the same target GFP sequence was not, showing that DNA methylation accompanying PTGS was influenced both by the level and origin of sRNAs, and possibly also by the epigenetic state of the locus. UT silencing appeared to be the least effective and resembled classical sense PTGS. The best responding UT lines behaved relatively heterogeneously possibly due to complexly arranged T-DNA insertions. Unlike IR and AS variants that fully restored GFP expression upon removal of the inducer, only partial reactivation was observed in some UT lines. Our results pointed out several not yet described phenomena and differences between the long-known silencer variants that may direct further research and affect selection of proper silencer variants for specific applications.
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Affiliation(s)
- Vojtěch Čermák
- Charles University, Faculty of Science, Department of Experimental Plant Biology, Viničná 5, Prague 2 128 44, Czech Republic
| | - Dimitrij Tyč
- Charles University, Faculty of Science, Department of Experimental Plant Biology, Viničná 5, Prague 2 128 44, Czech Republic
| | - Adéla Přibylová
- Charles University, Faculty of Science, Department of Experimental Plant Biology, Viničná 5, Prague 2 128 44, Czech Republic
| | - Lukáš Fischer
- Charles University, Faculty of Science, Department of Experimental Plant Biology, Viničná 5, Prague 2 128 44, Czech Republic.
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Schwartz SH, Hendrix B, Hoffer P, Sanders RA, Zheng W. Carbon Dots for Efficient Small Interfering RNA Delivery and Gene Silencing in Plants. PLANT PHYSIOLOGY 2020; 184:647-657. [PMID: 32764133 PMCID: PMC7536711 DOI: 10.1104/pp.20.00733] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 07/13/2020] [Indexed: 05/05/2023]
Abstract
The initiation of RNA interference (RNAi) by topically applied small interfering RNA has potential applications for plant functional genomics, crop improvement and crop protection, but the primary obstacle for the development of this technology is the efficient delivery of RNAi effectors into the cell. The plant cell wall is a particularly challenging barrier for the delivery of macromolecules because many of the transfection agents that are commonly used with animal cells produce nanocomplexes that are significantly larger than the size exclusion limit of the cell wall. Here, we illustrate the use of a class of very small nanoparticles, called carbon dots, for delivering small interfering RNA into the model plants Nicotiana benthamiana and tomato (Solanum lycopersicum). Low-pressure spray application of these formulations with a spreading surfactant resulted in strong silencing of GFP transgenes in both species. The delivery efficacy of carbon dot formulations was also demonstrated by the silencing of endogenous genes that encode two subunits of magnesium chelatase, an enzyme necessary for chlorophyll synthesis. The strong visible phenotypes observed with the carbon dot-facilitated delivery were validated by measuring significant reductions in the target gene transcript and/or protein levels. Methods for the delivery of RNAi effectors into plants, such as the carbon dot formulations described here, could become valuable tools for gene silencing in plants with practical applications in plant functional genomics and agriculture.
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Affiliation(s)
| | | | - Paul Hoffer
- Bayer Crop Science, Woodland, California 95695
| | | | - Wei Zheng
- Bayer Crop Science, Woodland, California 95695
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40
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Fabrizio JJ, Rollins J, Bazinet CW, Wegener S, Koziy I, Daniel R, Lombardo V, Pryce D, Bharrat K, Innabi E, Villanobos M, Mendoza G, Ferrara E, Rodway S, Vicioso M, Siracusa V, Dailey E, Pronovost J, Innabi S, Patel V, DeSouza N, Quaranto D, Niknejad A. Tubulin-binding cofactor E-like (TBCEL), the protein product of the mulet gene, is required in the germline for the regulation of inter-flagellar microtubule dynamics during spermatid individualization. Biol Open 2020; 9:bio049080. [PMID: 32033965 PMCID: PMC7055396 DOI: 10.1242/bio.049080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 01/22/2020] [Indexed: 11/14/2022] Open
Abstract
Individual sperm cells are resolved from a syncytium during late step of spermiogenesis known as individualization, which is accomplished by an Individualization Complex (IC) composed of 64 investment cones. mulet encodes Tubulin-binding cofactor E-like (TBCEL), suggesting a role for microtubule dynamics in individualization. Indeed, a population of ∼100 cytoplasmic microtubules fails to disappear in mulet mutant testes during spermatogenesis. This persistence, detected using epi-fluorescence and electron microscopy, suggests that removal of these microtubules by TBCEL is a prerequisite for individualization. Immunofluorescence reveals TBCEL expression in elongated spermatid cysts. In addition, testes from mulet mutant males were rescued to wild type using tubulin-Gal4 to drive TBCEL expression, indicating that the mutant phenotype is caused by the lack of TBCEL. Finally, RNAi driven by bam-GAL4 successfully phenocopied mulet, confirming that mulet is required in the germline for individualization. We propose a model in which the cytoplasmic microtubules serve as alternate tracks for investment cones in mulet mutant testes.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- James J Fabrizio
- Division of Natural Sciences, College of Mt St Vincent, Bronx, NY 10471, USA
| | - Janet Rollins
- Division of Natural Sciences, College of Mt St Vincent, Bronx, NY 10471, USA
| | | | - Stephanie Wegener
- Leibniz Institute for Neurobiology Magdeburg, Department Genetics of Learning and Memory, 39118 Magdeburg, Germany
| | - Iryna Koziy
- Division of Natural Sciences, College of Mt St Vincent, Bronx, NY 10471, USA
| | - Rachel Daniel
- Division of Natural Sciences, College of Mt St Vincent, Bronx, NY 10471, USA
| | - Vincent Lombardo
- Division of Natural Sciences, College of Mt St Vincent, Bronx, NY 10471, USA
| | - Dwaine Pryce
- Division of Natural Sciences, College of Mt St Vincent, Bronx, NY 10471, USA
| | - Kavita Bharrat
- Division of Natural Sciences, College of Mt St Vincent, Bronx, NY 10471, USA
| | - Elissa Innabi
- Division of Natural Sciences, College of Mt St Vincent, Bronx, NY 10471, USA
| | - Marielle Villanobos
- Division of Natural Sciences, College of Mt St Vincent, Bronx, NY 10471, USA
| | - Gabriela Mendoza
- Division of Natural Sciences, College of Mt St Vincent, Bronx, NY 10471, USA
| | - Elisa Ferrara
- Division of Natural Sciences, College of Mt St Vincent, Bronx, NY 10471, USA
| | - Stephanie Rodway
- Division of Natural Sciences, College of Mt St Vincent, Bronx, NY 10471, USA
| | - Matthew Vicioso
- Division of Natural Sciences, College of Mt St Vincent, Bronx, NY 10471, USA
| | - Victoria Siracusa
- Division of Natural Sciences, College of Mt St Vincent, Bronx, NY 10471, USA
| | - Erin Dailey
- Division of Natural Sciences, College of Mt St Vincent, Bronx, NY 10471, USA
| | - Justin Pronovost
- Division of Natural Sciences, College of Mt St Vincent, Bronx, NY 10471, USA
| | - Simon Innabi
- Division of Natural Sciences, College of Mt St Vincent, Bronx, NY 10471, USA
| | - Vrutant Patel
- Division of Natural Sciences, College of Mt St Vincent, Bronx, NY 10471, USA
| | - Nicole DeSouza
- Division of Natural Sciences, College of Mt St Vincent, Bronx, NY 10471, USA
| | - Danielle Quaranto
- Division of Natural Sciences, College of Mt St Vincent, Bronx, NY 10471, USA
| | - Amir Niknejad
- Department of Mathematics, College of Mt St Vincent, Bronx, NY 10471, USA
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Cao J, Gursanscky NR, Fletcher SJ, Sawyer A, Wadia M, McKeough L, Coleman M, Dressel U, Taochy C, Mitter N, Vaucheret H, Carroll BJ. Can-Seq: a PCR and DNA sequencing strategy for identifying new alleles of known and candidate genes. PLANT METHODS 2020; 16:16. [PMID: 32082406 PMCID: PMC7017465 DOI: 10.1186/s13007-020-0555-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 01/17/2020] [Indexed: 06/10/2023]
Abstract
BACKGROUND Forward genetic screens are a powerful approach for identifying the genes contributing to a trait of interest. However, mutants arising in genes already known can obscure the identification of new genes contributing to the trait. Here, we describe a strategy called Candidate gene-Sequencing (Can-Seq) for rapidly identifying and filtering out mutants carrying new alleles of known and candidate genes. RESULTS We carried out a forward genetic screen and identified 40 independent Arabidopsis mutants with defects in systemic spreading of RNA interference (RNAi), or more specifically in root-to-shoot transmission of post-transcriptional gene silencing (rtp). To classify the mutants as either representing a new allele of a known or candidate gene versus carrying a mutation in an undiscovered gene, bulk genomic DNA from up to 23 independent mutants was used as template to amplify a collection of 47 known or candidate genes. These amplified sequences were combined into Can-Seq libraries and deep sequenced. Subsequently, mutations in the known and candidate genes were identified using a custom Snakemake script (https://github.com/Carroll-Lab/can_seq), and PCR zygosity tests were then designed and used to identify the individual mutants carrying each mutation. Using this approach, we showed that 28 of the 40 rtp mutants carried homozygous nonsense, missense or splice site mutations in one or more of the 47 known or candidate genes. We conducted complementation tests to demonstrate that several of the candidate mutations were responsible for the rtp defect. Importantly, by exclusion, the Can-Seq pipeline also identified rtp mutants that did not carry a causative mutation in any of the 47 known and candidate genes, and these mutants represent an undiscovered gene(s) required for systemic RNAi. CONCLUSIONS Can-Seq offers an accurate, cost-effective method for classifying new mutants into known versus unknown genes. It has several advantages over existing genetic and DNA sequencing approaches that are currently being used in forward genetic screens for gene discovery. Using Can-Seq in conjunction with map-based gene cloning is a cost-effective approach towards identifying the full complement of genes contributing to a trait of interest.
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Affiliation(s)
- Jiangling Cao
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072 Australia
| | - Nial R. Gursanscky
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072 Australia
| | - Stephen J. Fletcher
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072 Australia
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, Brisbane, QLD 4072 Australia
| | - Anne Sawyer
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072 Australia
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, Brisbane, QLD 4072 Australia
| | - Mehershad Wadia
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072 Australia
| | - Lachlan McKeough
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072 Australia
| | - Marek Coleman
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072 Australia
| | - Uwe Dressel
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072 Australia
| | - Christelle Taochy
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072 Australia
- Institut Jean-Pierre Bourgin, UMR 1318, INRA AgroParisTech CNRS, Université Paris-Saclay, 78000 Versailles, France
| | - Neena Mitter
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, Brisbane, QLD 4072 Australia
| | - Hervé Vaucheret
- Institut Jean-Pierre Bourgin, UMR 1318, INRA AgroParisTech CNRS, Université Paris-Saclay, 78000 Versailles, France
| | - Bernard J. Carroll
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072 Australia
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Abstract
The coordination of cell fate decisions within complex multicellular structures rests on intercellular communication. To generate ordered patterns, cells need to know their relative positions within the growing structure. This is commonly achieved via the production and perception of mobile signaling molecules. In animal systems, such positional signals often act as morphogens and subdivide a field of cells into domains of discrete cell identities using a threshold-based readout of their mobility gradient. Reflecting the independent origin of multicellularity, plants evolved distinct signaling mechanisms to drive cell fate decisions. Many of the basic principles underlying developmental patterning are, however, shared between animals and plants, including the use of signaling gradients to provide positional information. In plant development, small RNAs can act as mobile instructive signals, and similar to classical morphogens in animals, employ a threshold-based readout of their mobility gradient to generate precisely defined cell fate boundaries. Given the distinctive nature of peptide morphogens and small RNAs, how might mechanisms underlying the function of traditionally morphogens be adapted to create morphogen-like behavior using small RNAs? In this review, we highlight the contributions of mobile small RNAs to pattern formation in plants and summarize recent studies that have advanced our understanding regarding the formation, stability, and interpretation of small RNA gradients.
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Affiliation(s)
- Simon Klesen
- Center for Plant Molecular Biology, University of Tübingen, Tübingen, Germany
| | - Kristine Hill
- Center for Plant Molecular Biology, University of Tübingen, Tübingen, Germany
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43
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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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44
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Taochy C, Yu A, Bouché N, Bouteiller N, Elmayan T, Dressel U, Carroll BJ, Vaucheret H. Post-transcriptional gene silencing triggers dispensable DNA methylation in gene body in Arabidopsis. Nucleic Acids Res 2019; 47:9104-9114. [PMID: 31372641 PMCID: PMC6753489 DOI: 10.1093/nar/gkz636] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 06/27/2019] [Accepted: 07/26/2019] [Indexed: 11/14/2022] Open
Abstract
Spontaneous post-transcriptional silencing of sense transgenes (S-PTGS) is established in each generation and is accompanied by DNA methylation, but the pathway of PTGS-dependent DNA methylation is unknown and so is its role. Here we show that CHH and CHG methylation coincides spatially and temporally with RDR6-dependent products derived from the central and 3' regions of the coding sequence, and requires the components of the RNA-directed DNA methylation (RdDM) pathway NRPE1, DRD1 and DRM2, but not CLSY1, NRPD1, RDR2 or DCL3, suggesting that RDR6-dependent products, namely long dsRNAs and/or siRNAs, trigger PTGS-dependent DNA methylation. Nevertheless, none of these RdDM components are required to establish S-PTGS or produce a systemic silencing signal. Moreover, preventing de novo DNA methylation in non-silenced transgenic tissues grafted onto homologous silenced tissues does not inhibit the triggering of PTGS. Overall, these data indicate that gene body DNA methylation is a consequence, not a cause, of PTGS, and rule out the hypothesis that a PTGS-associated DNA methylation signal is transmitted independent of a PTGS signal.
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Affiliation(s)
- Christelle Taochy
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000, Versailles, France
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Qld 4072, Australia
| | - Agnès Yu
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000, Versailles, France
| | - Nicolas Bouché
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000, Versailles, France
| | - Nathalie Bouteiller
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000, Versailles, France
| | - Taline Elmayan
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000, Versailles, France
| | - Uwe Dressel
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Qld 4072, Australia
| | - Bernard J Carroll
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Qld 4072, Australia
| | - Hervé Vaucheret
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000, Versailles, France
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45
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Chapman K, Taleski M, Ogilvie HA, Imin N, Djordjevic MA. CEP-CEPR1 signalling inhibits the sucrose-dependent enhancement of lateral root growth. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:3955-3967. [PMID: 31056646 PMCID: PMC6685651 DOI: 10.1093/jxb/erz207] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 04/29/2019] [Indexed: 05/22/2023]
Abstract
Lateral root (LR) proliferation is a major determinant of soil nutrient uptake. How resource allocation controls the extent of LR growth remains unresolved. We used genetic, physiological, transcriptomic, and grafting approaches to define a role for C-TERMINALLY ENCODED PEPTIDE RECEPTOR 1 (CEPR1) in controlling sucrose-dependent LR growth. CEPR1 inhibited LR growth in response to applied sucrose, other metabolizable sugars, and elevated light intensity. Pathways through CEPR1 restricted LR growth by reducing LR meristem size and the length of mature LR cells. RNA-sequencing of wild-type (WT) and cepr1-1 roots with or without sucrose treatment revealed an intersection of CEP-CEPR1 signalling with the sucrose transcriptional response. Sucrose up-regulated several CEP genes, supporting a specific role for CEP-CEPR1 in the response to sucrose. Moreover, genes with basally perturbed expression in cepr1-1 overlap with WT sucrose-responsive genes significantly. We found that exogenous CEP inhibited LR growth via CEPR1 by reducing LR meristem size and mature cell length. This result is consistent with CEP-CEPR1 acting to curtail the extent of sucrose-dependent LR growth. Reciprocal grafting indicates that LR growth inhibition requires CEPR1 in both the roots and shoots. Our results reveal a new role for CEP-CEPR1 signalling in controlling LR growth in response to sucrose.
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Affiliation(s)
- Kelly Chapman
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, ACT, Australia
| | - Michael Taleski
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, ACT, Australia
| | - Huw A Ogilvie
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, ACT, Australia
- Present address: Department of Computer Science, Rice University, Houston, TX 77005, USA
| | - Nijat Imin
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, ACT, Australia
- Present address: School of Biological Sciences, The University of Auckland, Auckland 1010, New Zealand
| | - Michael A Djordjevic
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, ACT, Australia
- Correspondence:
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Catch Me If You Can! RNA Silencing-Based Improvement of Antiviral Plant Immunity. Viruses 2019; 11:v11070673. [PMID: 31340474 PMCID: PMC6669615 DOI: 10.3390/v11070673] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 07/11/2019] [Accepted: 07/17/2019] [Indexed: 12/27/2022] Open
Abstract
Viruses are obligate parasites which cause a range of severe plant diseases that affect farm productivity around the world, resulting in immense annual losses of yield. Therefore, control of viral pathogens continues to be an agronomic and scientific challenge requiring innovative and ground-breaking strategies to meet the demands of a growing world population. Over the last decade, RNA silencing has been employed to develop plants with an improved resistance to biotic stresses based on their function to provide protection from invasion by foreign nucleic acids, such as viruses. This natural phenomenon can be exploited to control agronomically relevant plant diseases. Recent evidence argues that this biotechnological method, called host-induced gene silencing, is effective against sucking insects, nematodes, and pathogenic fungi, as well as bacteria and viruses on their plant hosts. Here, we review recent studies which reveal the enormous potential that RNA-silencing strategies hold for providing an environmentally friendly mechanism to protect crop plants from viral diseases.
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47
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Kalyandurg PB, Tahmasebi A, Vetukuri RR, Kushwaha SK, Lezzhov AA, Solovyev AG, Grenville-Briggs LJ, Savenkov EI. Efficient RNA silencing suppression activity of Potato Mop-Top Virus 8K protein is driven by variability and positive selection. Virology 2019; 535:111-121. [PMID: 31299487 DOI: 10.1016/j.virol.2019.06.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 06/27/2019] [Accepted: 06/29/2019] [Indexed: 12/31/2022]
Abstract
Previously, we investigated the evolution of Potato mop-top virus (PMTV) ORFs. Results indicate that positive selection acts exclusively on an ORF encoding the 8K protein, a weak viral suppressor of RNA silencing (VSR). However, how the extraordinary variability contributes to 8K-mediated RNA silencing suppression remains unknown. Here, we characterized the RNA silencing suppression activity of the 8K protein from seven diverse isolates. We show that 8K encoded by isolate P1 exhibits stronger RNA silencing suppression activity than the 8K protein from six other isolates. Mutational analyses revealed that Ser-50 is critical for these differences. By comparing small RNA profiles we found a lower abundance of siRNAs with U residue at the 5'-terminus after expression of the P1 8K compared to expression of 8K from isolate P125, an isolate with weak VSR activity. These results provide new clues as to the role of positive selection in shaping activities of VSRs.
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Affiliation(s)
- Pruthvi B Kalyandurg
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Linnean Center for Plant Biology, Uppsala, Sweden
| | - Aminallah Tahmasebi
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Linnean Center for Plant Biology, Uppsala, Sweden; Plant Virology Research Centre, College of Agriculture, Shiraz University, Iran
| | - Ramesh R Vetukuri
- Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp, Sweden
| | - Sandeep K Kushwaha
- Department of Plant Breeding, Swedish University of Agricultural Sciences, Alnarp, Sweden
| | - Alexander A Lezzhov
- Faculty of Bioengineering and Bioinformatics, Moscow State University, Moscow, Russia
| | - Andrey G Solovyev
- Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, Russia; Department of Virology Biological Faculty, Moscow State University, Moscow, Russia
| | - Laura J Grenville-Briggs
- Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Alnarp, Sweden
| | - Eugene I Savenkov
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Linnean Center for Plant Biology, Uppsala, Sweden.
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48
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Pinto SC, Mendes MA, Coimbra S, Tucker MR. Revisiting the Female Germline and Its Expanding Toolbox. TRENDS IN PLANT SCIENCE 2019; 24:455-467. [PMID: 30850278 DOI: 10.1016/j.tplants.2019.02.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Revised: 01/28/2019] [Accepted: 02/04/2019] [Indexed: 05/27/2023]
Abstract
The Arabidopsis thaliana ovule arises as a female reproductive organ composed solely of somatic diploid cells. Among them, one cell will acquire a unique identity and initiate female germline development. In this review we explore the complex network that facilitates differentiation of this single cell, and consider how it becomes committed to a distinct developmental program. We highlight recent progress towards understanding the role of intercellular communication, cell competency, and cell-cycle regulation in the ovule primordium, and we discuss the possibility that distinct pathways restrict germline development at different stages. Importantly, these recent findings suggest a renaissance in plant ovule research, restoring the female germline as an attractive model to study cell communication and cell fate establishment in multicellular organs.
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Affiliation(s)
- Sara C Pinto
- Departamento de Biologia, Faculdade de Ciências da Universidade do Porto, 4169-007 Porto, Portugal; GreenUPorto, Sustainable AgriFood Production Research Centre, Rua da Agrária 747, 4485-646 Vairão, Portugal
| | - Marta A Mendes
- Dipartimento di Bioscienze, Università degli Studi di Milano, Via Celoria 26, 20133 Milano, Italy
| | - Sílvia Coimbra
- Departamento de Biologia, Faculdade de Ciências da Universidade do Porto, 4169-007 Porto, Portugal; GreenUPorto, Sustainable AgriFood Production Research Centre, Rua da Agrária 747, 4485-646 Vairão, Portugal
| | - Matthew R Tucker
- School of Agriculture, Food, and Wine, The University of Adelaide, Waite Campus, Urrbrae, SA 5064, Australia.
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Zhang H, Demirer GS, Zhang H, Ye T, Goh NS, Aditham AJ, Cunningham FJ, Fan C, Landry MP. DNA nanostructures coordinate gene silencing in mature plants. Proc Natl Acad Sci U S A 2019; 116:7543-7548. [PMID: 30910954 PMCID: PMC6462094 DOI: 10.1073/pnas.1818290116] [Citation(s) in RCA: 127] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Delivery of biomolecules to plants relies on Agrobacterium infection or biolistic particle delivery, the former of which is amenable only to DNA delivery. The difficulty in delivering functional biomolecules such as RNA to plant cells is due to the plant cell wall, which is absent in mammalian cells and poses the dominant physical barrier to biomolecule delivery in plants. DNA nanostructure-mediated biomolecule delivery is an effective strategy to deliver cargoes across the lipid bilayer of mammalian cells; however, nanoparticle-mediated delivery without external mechanical aid remains unexplored for biomolecule delivery across the cell wall in plants. Herein, we report a systematic assessment of different DNA nanostructures for their ability to internalize into cells of mature plants, deliver siRNAs, and effectively silence a constitutively expressed gene in Nicotiana benthamiana leaves. We show that nanostructure internalization into plant cells and corresponding gene silencing efficiency depends on the DNA nanostructure size, shape, compactness, stiffness, and location of the siRNA attachment locus on the nanostructure. We further confirm that the internalization efficiency of DNA nanostructures correlates with their respective gene silencing efficiencies but that the endogenous gene silencing pathway depends on the siRNA attachment locus. Our work establishes the feasibility of biomolecule delivery to plants with DNA nanostructures and both details the design parameters of importance for plant cell internalization and also assesses the impact of DNA nanostructure geometry for gene silencing mechanisms.
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Affiliation(s)
- Huan Zhang
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720
| | - Gozde S Demirer
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720
| | - Honglu Zhang
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
| | - Tianzheng Ye
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720
| | - Natalie S Goh
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720
| | - Abhishek J Aditham
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720
| | - Francis J Cunningham
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720
| | - Chunhai Fan
- Division of Physical Biology & Bioimaging Center, Shanghai Synchrotron Radiation Facility, Chinese Academy of Sciences Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Markita P Landry
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720;
- Innovative Genomics Institute, Berkeley, CA 94720
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, CA 94720
- Chan-Zuckerberg Biohub, San Francisco, CA 94158
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50
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Katsarou K, Mitta E, Bardani E, Oulas A, Dadami E, Kalantidis K. DCL-suppressed Nicotiana benthamiana plants: valuable tools in research and biotechnology. MOLECULAR PLANT PATHOLOGY 2019; 20:432-446. [PMID: 30343523 PMCID: PMC6637889 DOI: 10.1111/mpp.12761] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
RNA silencing is a universal mechanism involved in development, epigenetic modifications and responses to biotic and abiotic stresses. The major components of this mechanism are Dicer-like (DCL), Argonaute (AGO) and RNA-dependent RNA polymerase (RDR) proteins. Understanding the role of each component is of great scientific and agronomic importance. Plants, including Nicotiana benthamiana, an important plant model, usually possess four DCL proteins, each of which has a specific role, namely being responsible for the production of an exclusive small RNA population. Here, we used RNA interference (RNAi) technology to target DCL proteins and produced single and combinatorial mutants for DCL. We analysed the phenotype for each DCL knockdown plant, together with the small RNA profile, by next-generation sequencing (NGS). We also investigated transgene expression, as well as viral infections, and were able to show that DCL suppression results in distinct developmental defects, changes in small RNA populations, increases in transgene expression and, finally, higher susceptibility in certain RNA viruses. Therefore, these plants are excellent tools for the following: (i) to study the role of DCL enzymes; (ii) to overexpress proteins of interest; and (iii) to understand the complex relationship between the plant silencing mechanism and biotic or abiotic stresses.
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Affiliation(s)
- Konstantina Katsarou
- Institute of Molecular Biology and BiotechnologyFoundation for Research and Technology‐HellasHeraklionGreece
| | - Eleni Mitta
- Department of BiologyUniversity of CreteHeraklionGreece
| | | | - Anastasis Oulas
- Institute of Molecular Biology and BiotechnologyFoundation for Research and Technology‐HellasHeraklionGreece
- Present address:
Bioinformatics Group, The Cyprus Institute of Neurology and GeneticsNicosiaCyprus
| | - Elena Dadami
- Department of BiologyUniversity of CreteHeraklionGreece
- Present address:
RLP AgroScience, AlPlantaNeustadtGermany
| | - Kriton Kalantidis
- Institute of Molecular Biology and BiotechnologyFoundation for Research and Technology‐HellasHeraklionGreece
- Department of BiologyUniversity of CreteHeraklionGreece
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