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Kim JH, Yu J, Kim JY, Park YJ, Bae S, Kang KK, Jung YJ. Phenotypic characterization of pre-harvest sprouting resistance mutants generated by the CRISPR/Cas9-geminiviral replicon system in rice. BMB Rep 2024; 57:79-85. [PMID: 38303561 PMCID: PMC10910094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 12/02/2023] [Accepted: 12/03/2023] [Indexed: 02/03/2024] Open
Abstract
Pre-harvest sprouting is a critical phenomenon involving germination of seeds in the mother plant before harvest under relative humid conditions and reduced dormancy. In this paper, we generated HDR mutant lines with one region SNP (C/T) and an insertion of 6 bp (GGT/GGTGGCGGC) in OsERF1 genes for pre-harvest sprouting (PHS) resistance using CRISPR/Cas9 and a geminiviral replicon system. The incidence of HDR was 2.6% in transformed calli. T1 seeds were harvested from 12 HDR-induced calli and named ERF1-hdr line. Molecular stability, key agronomic properties, physiological properties, and biochemical properties of target genes in the ERF1-hdr line were investigated for three years. The ERF1-hdr line showed significantly enhanced seed dormancy and pre-harvest sprouting resistance. qRT-PCR analysis suggested that enhanced ABA signaling resulted in a stronger phenotype of PHS resistance. These results indicate that efficient HDR can be achieved through SNP/InDel replacement using a single and modular configuration applicable to different rice targets and other crops. This work demonstrates the potential to replace all genes with elite alleles within one generation and greatly expands our ability to improve agriculturally important traits. [BMB Reports 2024; 57(2): 79-85].
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Affiliation(s)
- Jong Hee Kim
- Division of Horticultural Biotechnology, School of Biotechnology, Hankyong National University, Anseong 17579, Korea
- Institute of Genetic Engineering, Hankyong National University, Anseong 17579, Korea
| | - Jihyeon Yu
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul 03080, Korea
| | - Jin Young Kim
- Division of Horticultural Biotechnology, School of Biotechnology, Hankyong National University, Anseong 17579, Korea
| | - Yong Jin Park
- Department of Plant Resources, College of Industrial Sciences, Kongju National University, Yesan 32439, Korea
| | - Sangsu Bae
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul 03080, Korea
| | - Kwon Kyoo Kang
- Division of Horticultural Biotechnology, School of Biotechnology, Hankyong National University, Anseong 17579, Korea
- Institute of Genetic Engineering, Hankyong National University, Anseong 17579, Korea
| | - Yu Jin Jung
- Division of Horticultural Biotechnology, School of Biotechnology, Hankyong National University, Anseong 17579, Korea
- Institute of Genetic Engineering, Hankyong National University, Anseong 17579, Korea
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2
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Kim JH, Yu J, Kim HK, Kim JY, Kim MS, Cho YG, Bae S, Kang KK, Jung YJ. Genome Editing of Golden SNP-Carrying Lycopene Epsilon-Cyclase (LcyE) Gene Using the CRSPR-Cas9/HDR and Geminiviral Replicon System in Rice. Int J Mol Sci 2022; 23:ijms231810383. [PMID: 36142294 PMCID: PMC9499184 DOI: 10.3390/ijms231810383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 08/30/2022] [Accepted: 09/04/2022] [Indexed: 11/16/2022] Open
Abstract
Lycopene epsilon-cyclase (LcyE) is a key enzyme in the carotenoid biosynthetic pathway of higher plants. Using the CRSPR/Cas9 and the geminiviral replicon, we optimized a method for targeted mutagenesis and golden SNP replacement of the LcyE gene in rice. We have exploited the geminiviral replicon amplification as a means to provide a large amount of donor template for the repair of a CRISPR-Cas-induced DNA double-strand break (DSB) in the target gene via homology-directed repair (HDR). Mutagenesis experiments performed on the Donggin variety achieved precise modification of the LcyE loci with an efficiency of up to 90%. In HDR experiments, our target was the LcyE allele (LcyE-H523L) derived from anther culture containing a golden SNP replacement. The phenotype of the homologous recombination (HR) mutant obtained through the geminiviral replicon-based template delivery system was tangerine color, and the frequency was 1.32% of the transformed calli. In addition, the total carotenoid content of the LcyEsg2-HDR1 and LcyEsg2-HDR2 lines was 6.8–9.6 times higher than that of the wild-type (WT) calli, respectively. The reactive oxygen species content was lower in the LcyEsg2-HDR1 and LcyEsg2-HDR2 lines. These results indicate that efficient HDR can be achieved in the golden SNP replacement using a single and modular configuration applicable to different rice targets and other crops. This work demonstrates the potential to replace all genes with elite alleles within one generation and greatly expands our ability to improve agriculturally important traits.
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Affiliation(s)
- Jong Hee Kim
- Division of Horticultural Biotechnology, School of Biotechnology, Hankyong National University, Anseong 17579, Korea
| | - Jihyeon Yu
- Division of Life Sciences, Korea Polar Research Institute, Incheon 21990, Korea
| | - Hee Kyoung Kim
- Division of Horticultural Biotechnology, School of Biotechnology, Hankyong National University, Anseong 17579, Korea
| | - Jin Young Kim
- Division of Horticultural Biotechnology, School of Biotechnology, Hankyong National University, Anseong 17579, Korea
| | - Me-Sun Kim
- Department of Crop Science, Chungbuk National University, Cheongju 28644, Korea
| | - Yong-Gu Cho
- Department of Crop Science, Chungbuk National University, Cheongju 28644, Korea
| | - Sangsu Bae
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Korea
| | - Kwon Kyoo Kang
- Division of Horticultural Biotechnology, School of Biotechnology, Hankyong National University, Anseong 17579, Korea
- Institute of Genetic Engineering, Hankyong National University, Anseong 17579, Korea
| | - Yu Jin Jung
- Division of Horticultural Biotechnology, School of Biotechnology, Hankyong National University, Anseong 17579, Korea
- Institute of Genetic Engineering, Hankyong National University, Anseong 17579, Korea
- Correspondence: ; Tel.: +82-31-670-5101
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Chen H, Neubauer M, Wang JP. Enhancing HR Frequency for Precise Genome Editing in Plants. FRONTIERS IN PLANT SCIENCE 2022; 13:883421. [PMID: 35592579 PMCID: PMC9113527 DOI: 10.3389/fpls.2022.883421] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 03/29/2022] [Indexed: 06/15/2023]
Abstract
Gene-editing tools, such as Zinc-fingers, TALENs, and CRISPR-Cas, have fostered a new frontier in the genetic improvement of plants across the tree of life. In eukaryotes, genome editing occurs primarily through two DNA repair pathways: non-homologous end joining (NHEJ) and homologous recombination (HR). NHEJ is the primary mechanism in higher plants, but it is unpredictable and often results in undesired mutations, frameshift insertions, and deletions. Homology-directed repair (HDR), which proceeds through HR, is typically the preferred editing method by genetic engineers. HR-mediated gene editing can enable error-free editing by incorporating a sequence provided by a donor template. However, the low frequency of native HR in plants is a barrier to attaining efficient plant genome engineering. This review summarizes various strategies implemented to increase the frequency of HDR in plant cells. Such strategies include methods for targeting double-strand DNA breaks, optimizing donor sequences, altering plant DNA repair machinery, and environmental factors shown to influence HR frequency in plants. Through the use and further refinement of these methods, HR-based gene editing may one day be commonplace in plants, as it is in other systems.
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Affiliation(s)
- Hao Chen
- Department of Plant and Microbial Biology, Program in Genetics, North Carolina State University, Raleigh, NC, United States
- College of Forestry, Shandong Agricultural University, Tai’an, China
| | - Matthew Neubauer
- Department of Plant and Microbial Biology, Program in Genetics, North Carolina State University, Raleigh, NC, United States
| | - Jack P. Wang
- Department of Forestry and Environmental Resources, Forest Biotechnology Group, North Carolina State University, Raleigh, NC, United States
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin, China
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4
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Chen J, Li S, He Y, Li J, Xia L. An update on precision genome editing by homology-directed repair in plants. PLANT PHYSIOLOGY 2022; 188:1780-1794. [PMID: 35238390 PMCID: PMC8968426 DOI: 10.1093/plphys/kiac037] [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: 11/12/2021] [Accepted: 01/20/2022] [Indexed: 05/22/2023]
Abstract
Beneficial alleles derived from local landraces or related species, or even orthologs from other plant species, are often caused by differences of one or several single-nucleotide polymorphisms or indels in either the promoter region or the encoding region of a gene and often account for major differences in agriculturally important traits. Clustered regularly interspaced short palindromic repeats-associated endonuclease Cas9 system (CRISPR/Cas9)-mediated precision genome editing enables targeted allele replacement or insertion of flag or foreign genes at specific loci via homology-directed repair (HDR); however, HDR efficiency is low due to the intrinsic rare occurrence of HDR and insufficient DNA repair template in the proximity of a double-stranded break (DSB). Precise replacement of the targeted gene with elite alleles from landraces or relatives into a commercial variety through genome editing has been a holy grail in the crop genome editing field. In this update, we briefly summarize CRISPR/Cas-mediated HDR in plants. We describe diverse strategies to improve HDR efficiency by manipulating the DNA repair pathway, timing DSB induction, and donor delivery, and so on. Lastly, we outline open questions and challenges in HDR-mediated precision genome editing in both plant biological research and crop improvement.
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Affiliation(s)
| | | | - Yubing He
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China
| | - Jingying Li
- Institute of Crop Sciences (ICS), Chinese Academy of Agricultural Sciences (CAAS), Beijing 100081, China
- National Nanfan Research Institute (Sanya), Chinese Academy of Agricultural Sciences/Hainan Yazhou Bay Seed Laboratory, Sanya 572024, China
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DNA Double-Strand Break Repairs and Their Application in Plant DNA Integration. Genes (Basel) 2022; 13:genes13020322. [PMID: 35205367 PMCID: PMC8871565 DOI: 10.3390/genes13020322] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 02/07/2022] [Accepted: 02/07/2022] [Indexed: 01/25/2023] Open
Abstract
Double-strand breaks (DSBs) are considered to be one of the most harmful and mutagenic forms of DNA damage. They are highly toxic if unrepaired, and can cause genome rearrangements and even cell death. Cells employ two major pathways to repair DSBs: homologous recombination (HR) and non-homologous end-joining (NHEJ). In plants, most applications of genome modification techniques depend on the development of DSB repair pathways, such as Agrobacterium-mediated transformation (AMT) and gene targeting (GT). In this paper, we review the achieved knowledge and recent advances on the DNA DSB response and its main repair pathways; discuss how these pathways affect Agrobacterium-mediated T-DNA integration and gene targeting in plants; and describe promising strategies for producing DSBs artificially, at definite sites in the genome.
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Peterson D, Barone P, Lenderts B, Schwartz C, Feigenbutz L, St. Clair G, Jones S, Svitashev S. Advances in Agrobacterium transformation and vector design result in high-frequency targeted gene insertion in maize. PLANT BIOTECHNOLOGY JOURNAL 2021; 19:2000-2010. [PMID: 33934470 PMCID: PMC8486252 DOI: 10.1111/pbi.13613] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 04/13/2021] [Accepted: 04/26/2021] [Indexed: 05/03/2023]
Abstract
CRISPR-Cas is a powerful DNA double-strand break technology with wide-ranging applications in plant genome modification. However, the efficiency of genome editing depends on various factors including plant genetic transformation processes and types of modifications desired. Agrobacterium infection is the preferred method of transformation and delivery of editing components into the plant cell. While this method has been successfully used to generate gene knockouts in multiple crops, precise nucleotide replacement and especially gene insertion into a pre-defined genomic location remain highly challenging. Here, we report an efficient, selectable marker-free site-specific gene insertion in maize using Agrobacterium infection. Advancements in maize transformation and new vector design enabled increase of targeted insertion frequencies by two orders of magnitude in comparison to conventional Agrobacterium-mediated delivery. Importantly, these advancements allowed not only a significant improvement of the frequency, but also of the quality of generated events. These results further enable the application of genome editing for trait product development in a wide variety of crop species amenable to Agrobacterium-mediated transformation.
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Huang TK, Puchta H. Novel CRISPR/Cas applications in plants: from prime editing to chromosome engineering. Transgenic Res 2021; 30:529-549. [PMID: 33646511 PMCID: PMC8316200 DOI: 10.1007/s11248-021-00238-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 02/13/2021] [Indexed: 12/26/2022]
Abstract
In the last years, tremendous progress has been made in the development of CRISPR/Cas-mediated genome editing tools. A number of natural CRISPR/Cas nuclease variants have been characterized. Engineered Cas proteins have been developed to minimize PAM restrictions, off-side effects and temperature sensitivity. Both kinds of enzymes have, by now, been applied widely and efficiently in many plant species to generate either single or multiple mutations at the desired loci by multiplexing. In addition to DSB-induced mutagenesis, specifically designed CRISPR/Cas systems allow more precise gene editing, resulting not only in random mutations but also in predefined changes. Applications in plants include gene targeting by homologous recombination, base editing and, more recently, prime editing. We will evaluate these different technologies for their prospects and practical applicability in plants. In addition, we will discuss a novel application of the Cas9 nuclease in plants, enabling the induction of heritable chromosomal rearrangements, such as inversions and translocations. This technique will make it possible to change genetic linkages in a programmed way and add another level of genome engineering to the toolbox of plant breeding. Also, strategies for tissue culture free genome editing were developed, which might be helpful to overcome the transformation bottlenecks in many crops. All in all, the recent advances of CRISPR/Cas technology will help agriculture to address the challenges of the twenty-first century related to global warming, pollution and the resulting food shortage.
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Affiliation(s)
- Teng-Kuei Huang
- Botanical Institute II, Karlsruhe Institute of Technology, POB 6980, 76049, Karlsruhe, Germany
| | - Holger Puchta
- Botanical Institute II, Karlsruhe Institute of Technology, POB 6980, 76049, Karlsruhe, Germany.
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Oz MT, Altpeter A, Karan R, Merotto A, Altpeter F. CRISPR/Cas9-Mediated Multi-Allelic Gene Targeting in Sugarcane Confers Herbicide Tolerance. Front Genome Ed 2021; 3:673566. [PMID: 34713261 PMCID: PMC8525412 DOI: 10.3389/fgeed.2021.673566] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 05/28/2021] [Indexed: 12/27/2022] Open
Abstract
Sugarcane is the source of 80% of the sugar and 26% of the bioethanol produced globally. However, its complex, highly polyploid genome (2n = 100 - 120) impedes crop improvement. Here, we report efficient and reproducible gene targeting (GT) in sugarcane, enabling precise co-editing of multiple alleles via template-mediated and homology-directed repair (HDR) of DNA double strand breaks induced by the programmable nuclease CRISPR/Cas9. The evaluation of 146 independently transformed plants from five independent experiments revealed a targeted nucleotide replacement that resulted in both targeted amino acid substitutions W574L and S653I in the acetolactate synthase (ALS) in 11 lines in addition to single, targeted amino acid substitutions W574L or S653I in 25 or 18 lines, respectively. Co-editing of up to three ALS copies/alleles that confer herbicide tolerance was confirmed by Sanger sequencing of cloned long polymerase chain reaction (PCR) amplicons. This work will enable crop improvement by conversion of inferior alleles to superior alleles through targeted nucleotide substitutions.
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Affiliation(s)
- Mehmet Tufan Oz
- Agronomy Department, Plant Molecular and Cellular Biology Program, Genetics Institute, University of Florida, IFAS, Gainesville, FL, United States
- DOE Center for Advanced Bioenergy and Bioproducts Innovation, Gainesville, FL, United States
| | - Angelika Altpeter
- Agronomy Department, Plant Molecular and Cellular Biology Program, Genetics Institute, University of Florida, IFAS, Gainesville, FL, United States
| | - Ratna Karan
- Agronomy Department, Plant Molecular and Cellular Biology Program, Genetics Institute, University of Florida, IFAS, Gainesville, FL, United States
| | - Aldo Merotto
- Agronomy Department, Plant Molecular and Cellular Biology Program, Genetics Institute, University of Florida, IFAS, Gainesville, FL, United States
| | - Fredy Altpeter
- Agronomy Department, Plant Molecular and Cellular Biology Program, Genetics Institute, University of Florida, IFAS, Gainesville, FL, United States
- DOE Center for Advanced Bioenergy and Bioproducts Innovation, Gainesville, FL, United States
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Čermák T. Sequence modification on demand: search and replace tools for precise gene editing in plants. Transgenic Res 2021; 30:353-379. [PMID: 34086167 DOI: 10.1007/s11248-021-00253-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 04/05/2021] [Indexed: 12/26/2022]
Abstract
Until recently, our ability to generate allelic diversity in plants was limited to introduction of variants from domesticated and wild species by breeding via uncontrolled recombination or the use of chemical and physical mutagens-processes that are lengthy and costly or lack specificity, respectively. Gene editing provides a faster and more precise way to create new variation, although its application in plants has been dominated by the creation of short insertion and deletion mutations leading to loss of gene function, mostly due to the dependence of editing outcomes on DNA repair pathway choices intrinsic to higher eukaryotes. Other types of edits such as point mutations and precise and pre-designed targeted sequence insertions have rarely been implemented, despite providing means to modulate the expression of target genes or to engineer the function and stability of their protein products. Several advancements have been developed in recent years to facilitate custom editing by regulation of repair pathway choices or by taking advantage of alternative types of DNA repair. We have seen the advent of novel gene editing tools that are independent of DNA double-strand break repair, and methods completely independent of host DNA repair processes are being increasingly explored. With the aim to provide a comprehensive review of the state-of-the-art methodology for allele replacement in plants, I discuss the adoption of these improvements for plant genome engineering.
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Pearl Millet Blast Resistance: Current Status and Recent Advancements in Genomic Selection and Genome Editing Approaches. Fungal Biol 2021. [DOI: 10.1007/978-3-030-60585-8_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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11
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Barakate A, Keir E, Oakey H, Halpin C. Stimulation of homologous recombination in plants expressing heterologous recombinases. BMC PLANT BIOLOGY 2020; 20:336. [PMID: 32677892 PMCID: PMC7364528 DOI: 10.1186/s12870-020-02545-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 07/08/2020] [Indexed: 05/15/2023]
Abstract
BACKGROUND Current excitement about the opportunities for gene editing in plants have been prompted by advances in CRISPR/Cas and TALEN technologies. CRISPR/Cas is widely used to knock-out or modify genes by inducing targeted double-strand breaks (DSBs) which are repaired predominantly by error-prone non-homologous end-joining or microhomology-mediated end joining resulting in mutations that may alter or abolish gene function. Although such mutations are random, they occur at sufficient frequency to allow useful mutations to be routinely identified by screening. By contrast, gene knock-ins to replace entire genes with alternative alleles or copies with specific characterised modifications, is not yet routinely possible. Gene replacement (or gene targeting) by homology directed repair occurs at extremely low frequency in higher plants making screening for useful events unfeasible. Homology directed repair might be increased by inhibiting non-homologous end-joining and/or stimulating homologous recombination (HR). Here we pave the way to increasing gene replacement efficiency by evaluating the effect of expression of multiple heterologous recombinases on intrachromosomal homologous recombination (ICR) in Nicotiana tabacum plants. RESULTS We expressed several bacterial and human recombinases in different combinations in a tobacco transgenic line containing a highly sensitive β-glucuronidase (GUS)-based ICR substrate. Coordinated simultaneous expression of multiple recombinases was achieved using the viral 2A translational recoding system. We found that most recombinases increased ICR dramatically in pollen, where HR will be facilitated by the programmed DSBs that occur during meiosis. DMC1 expression produced the greatest stimulation of ICR in primary transformants, with one plant showing a 1000-fold increase in ICR frequency. Evaluation of ICR in homozygous T2 plant lines revealed increases in ICR of between 2-fold and 380-fold depending on recombinase(s) expressed. By comparison, ICR was only moderately increased in vegetative tissues and constitutive expression of heterologous recombinases also reduced plant fertility. CONCLUSION Expression of heterologous recombinases can greatly increase the frequency of HR in plant reproductive tissues. Combining such recombinase expression with the use of CRISPR/Cas9 to induce DSBs could be a route to radically improving gene replacement efficiency in plants.
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Affiliation(s)
- Abdellah Barakate
- Division of Plant Sciences, School of Life Sciences, University of Dundee at the JHI, Invergowrie, Dundee, DD2 5DA, Scotland
- Current address: Cell and Molecular Sciences, The James Hutton Institute, Invergowrie, Dundee, DD2 5DA, UK
| | - Ewan Keir
- Division of Plant Sciences, School of Life Sciences, University of Dundee at the JHI, Invergowrie, Dundee, DD2 5DA, Scotland
| | - Helena Oakey
- Division of Plant Sciences, School of Life Sciences, University of Dundee at the JHI, Invergowrie, Dundee, DD2 5DA, Scotland
| | - Claire Halpin
- Division of Plant Sciences, School of Life Sciences, University of Dundee at the JHI, Invergowrie, Dundee, DD2 5DA, Scotland.
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Zlobin NE, Lebedeva MV, Taranov VV. CRISPR/Cas9 genome editing through in planta transformation. Crit Rev Biotechnol 2020; 40:153-168. [PMID: 31903793 DOI: 10.1080/07388551.2019.1709795] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
In this review, the application of CRISPR/Cas9 plant genome editing using alternative transformation methods is discussed. Genome editing by the CRISPR/Cas9 system is usually implemented via the generation of transgenic plants carrying Cas9 and sgRNA genes in the genome. Transgenic plants are usually developed by in vitro regeneration from single transformed cells, which requires using different in vitro culture-based methods. Despite their common application, these methods have some disadvantages and limitations. Thus, some methods of plant transformation that do not depend on in vitro regeneration have been developed. These methods are known as "in planta" transformation. The main focus of this review is the so-called floral dip in planta transformation method, although other approaches are also described. The main features of in planta transformation in the context of CRISPR/Cas9 genome editing are discussed. Furthermore, multiple ways to increase the effectiveness of this approach and to broaden its use in different plant species are considered.
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Affiliation(s)
- Nikolay E Zlobin
- All-Russia Research Institute of Agricultural Biotechnology, Russian Academy of Sciences, Moscow, Russian
| | - Marina V Lebedeva
- All-Russia Research Institute of Agricultural Biotechnology, Russian Academy of Sciences, Moscow, Russian
| | - Vasiliy V Taranov
- All-Russia Research Institute of Agricultural Biotechnology, Russian Academy of Sciences, Moscow, Russian
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13
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Li S, Xia L. Precise gene replacement in plants through CRISPR/Cas genome editing technology: current status and future perspectives. ABIOTECH 2020; 1:58-73. [PMID: 36305005 PMCID: PMC9590512 DOI: 10.1007/s42994-019-00009-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 10/08/2019] [Indexed: 12/01/2022]
Abstract
CRISPR/Cas, as a simple, versatile, robust and cost-effective system for genome manipulation, has dominated the genome editing field over the past few years. The application of CRISPR/Cas in crop improvement is particularly important in the context of global climate change, as well as diverse agricultural, environmental and ecological challenges. Various CRISPR/Cas toolboxes have been developed and allow for targeted mutagenesis at specific genome loci, transcriptome regulation and epigenome editing, base editing, and precise targeted gene/allele replacement or tagging in plants. In particular, precise replacement of an existing allele with an elite allele in a commercial variety through homology-directed repair (HDR) is a holy grail in genome editing for crop improvement as it has been very difficult, laborious and time-consuming to introgress the elite alleles into commercial varieties without any linkage drag from parental lines within a few generations in crop breeding practice. However, it still remains very challenging in crop plants. This review intends to provide an informative summary of the latest development and breakthroughs in gene replacement using CRISPR/Cas technology, with a focus on achievements, potential mechanisms and future perspectives in plant biological science as well as crop improvement.
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Affiliation(s)
- Shaoya Li
- Institute of Crop Sciences (ICS), Chinese Academy of Agricultural Sciences (CAAS), Beijing, 100081 China
| | - Lanqin Xia
- Institute of Crop Sciences (ICS), Chinese Academy of Agricultural Sciences (CAAS), Beijing, 100081 China
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14
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Rozov SM, Permyakova NV, Deineko EV. The Problem of the Low Rates of CRISPR/Cas9-Mediated Knock-ins in Plants: Approaches and Solutions. Int J Mol Sci 2019; 20:E3371. [PMID: 31323994 PMCID: PMC6651222 DOI: 10.3390/ijms20133371] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 06/28/2019] [Accepted: 07/05/2019] [Indexed: 11/16/2022] Open
Abstract
The main number of genome editing events in plant objects obtained during the last decade with the help of specific nucleases zinc finger (ZFN), transcription activator-like effector nucleases (TALEN), and clustered regularly interspaced short palindromic repeats (CRISPR)/Cas are the microindels causing frameshift and subsequent gene knock-out. The knock-ins of genes or their parts, i.e., the insertion of them into a target genome region, are between one and two orders of magnitude less frequent. First and foremost, this is associated with the specific features of the repair systems of higher eukaryotes and the availability of the donor template in accessible proximity during double-strand break (DSB) repair. This review briefs the main repair pathways in plants according to the aspect of their involvement in genome editing. The main methods for increasing the frequency of knock-ins are summarized both along the homologous recombination pathway and non-homologous end joining, which can be used for plant objects.
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Affiliation(s)
- Serge M Rozov
- Institute of Cytology and Genetics, Siberian Branch, Russian Academy of Sciences, Novosibirsk 630090, Russia.
| | - Natalya V Permyakova
- Institute of Cytology and Genetics, Siberian Branch, Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Elena V Deineko
- Institute of Cytology and Genetics, Siberian Branch, Russian Academy of Sciences, Novosibirsk 630090, Russia
- Department of Plant Physiology and Biotechnology, Tomsk State University, Tomsk 634050, Russia
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15
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Mushtaq M, Sakina A, Wani SH, Shikari AB, Tripathi P, Zaid A, Galla A, Abdelrahman M, Sharma M, Singh AK, Salgotra RK. Harnessing Genome Editing Techniques to Engineer Disease Resistance in Plants. FRONTIERS IN PLANT SCIENCE 2019; 10:550. [PMID: 31134108 PMCID: PMC6514154 DOI: 10.3389/fpls.2019.00550] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 04/10/2019] [Indexed: 05/21/2023]
Abstract
Modern genome editing (GE) techniques, which include clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 9 (CRISPR/Cas9) system, transcription activator-like effector nucleases (TALENs), zinc-finger nucleases (ZFNs) and LAGLIDADG homing endonucleases (meganucleases), have so far been used for engineering disease resistance in crops. The use of GE technologies has grown very rapidly in recent years with numerous examples of targeted mutagenesis in crop plants, including gene knockouts, knockdowns, modifications, and the repression and activation of target genes. CRISPR/Cas9 supersedes all other GE techniques including TALENs and ZFNs for editing genes owing to its unprecedented efficiency, relative simplicity and low risk of off-target effects. Broad-spectrum disease resistance has been engineered in crops by GE of either specific host-susceptibility genes (S gene approach), or cleaving DNA of phytopathogens (bacteria, virus or fungi) to inhibit their proliferation. This review focuses on different GE techniques that can potentially be used to boost molecular immunity and resistance against different phytopathogens in crops, ultimately leading to the development of promising disease-resistant crop varieties.
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Affiliation(s)
- Muntazir Mushtaq
- School of Biotechnology, Sher-e-Kashmir University of Agricultural Sciences and Technology of Jammu, Jammu, India
| | - Aafreen Sakina
- Division of Plant Biotechnology, Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir, Srinagar, India
| | - Shabir Hussain Wani
- Mountain Research Center for Field Crops, Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir, Srinagar, India
| | - Asif B. Shikari
- Division of Plant Biotechnology, Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir, Srinagar, India
| | - Prateek Tripathi
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, United States
| | - Abbu Zaid
- Plant Physiology and Biochemistry Section, Department of Botany, Aligarh Muslim University, Aligarh, India
| | - Aravind Galla
- Department of Entomology, University of Arkansas, Fayetteville, AR, United States
| | - Mostafa Abdelrahman
- Arid Land Research Center, Tottori University, Tottori, Japan
- Botany Department, Faculty of Sciences, Aswan University, Aswan, Egypt
| | - Manmohan Sharma
- School of Biotechnology, Sher-e-Kashmir University of Agricultural Sciences and Technology of Jammu, Jammu, India
| | - Anil Kumar Singh
- School of Biotechnology, Sher-e-Kashmir University of Agricultural Sciences and Technology of Jammu, Jammu, India
| | - Romesh Kumar Salgotra
- School of Biotechnology, Sher-e-Kashmir University of Agricultural Sciences and Technology of Jammu, Jammu, India
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16
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Huang TK, Puchta H. CRISPR/Cas-mediated gene targeting in plants: finally a turn for the better for homologous recombination. PLANT CELL REPORTS 2019; 38:443-453. [PMID: 30673818 DOI: 10.1007/s00299-019-02379-0] [Citation(s) in RCA: 82] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 01/09/2019] [Indexed: 05/22/2023]
Abstract
We summarize recent progress of CRISPR/Cas9-mediated gene targeting in plants, provide recommendations for designing gene-targeting vectors and highlight the potential of new technologies applicable to plants. Gene targeting (GT) is a tool of urgent need for plant biotechnology and breeding. It is based on homologous recombination that is able to precisely introduce desired modifications within a target locus. However, its low efficiency in higher plants is a major barrier for its application. Using site-specific nucleases, such as the recent CRISPR/Cas system, GT has become applicable in plants, via the induction of double-strand breaks, although still at a too low efficiency for most practical applications in crops. Recently, a variety of promising new improvements regarding the efficiency of GT has been reported by several groups. It turns out that GT can be enhanced by cell-type-specific expression of Cas nucleases, by the use of self-amplified GT-vector DNA or by manipulation of DNA repair pathways. Here, we highlight the most recent progress of GT in plants. Moreover, we provide suggestions on how to use the technology efficiently, based on the mechanisms of DNA repair, and highlight several of the newest GT strategies in yeast or mammals that are potentially applicable to plants. Using the full potential of GT technology will definitely help us pave the way in enhancing crop yields and food safety for an ecologically friendly agriculture.
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Affiliation(s)
- Teng-Kuei Huang
- Botanical Institute II, Karlsruhe Institute of Technology, POB 6980, 76049, Karlsruhe, Germany
| | - Holger Puchta
- Botanical Institute II, Karlsruhe Institute of Technology, POB 6980, 76049, Karlsruhe, Germany.
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17
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Schmidt C, Pacher M, Puchta H. DNA Break Repair in Plants and Its Application for Genome Engineering. Methods Mol Biol 2019; 1864:237-266. [PMID: 30415341 DOI: 10.1007/978-1-4939-8778-8_17] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Genome engineering is a biotechnological approach to precisely modify the genetic code of a given organism in order to change the context of an existing sequence or to create new genetic resources, e.g., for obtaining improved traits or performance. Efficient targeted genome alterations are mainly based on the induction of DNA double-strand breaks (DSBs) or adjacent single-strand breaks (SSBs). Naturally, all organisms continuously have to deal with DNA-damaging factors challenging the genetic integrity, and therefore a wide range of DNA repair mechanisms have evolved. A profound understanding of the different repair pathways is a prerequisite to control and enhance targeted gene modifications. DSB repair can take place by nonhomologous end joining (NHEJ) or homology-dependent repair (HDR). As the main outcome of NHEJ-mediated repair is accompanied by small insertions and deletions, it is applicable to specifically knock out genes or to rearrange linkage groups or whole chromosomes. The basic requirement for HDR is the presence of a homologous template; thus this process can be exploited for targeted integration of ectopic sequences into the plant genome. The development of different types of artificial site-specific nucleases allows for targeted DSB induction in the plant genome. Such synthetic nucleases have been used for both qualitatively studying DSB repair in vivo with respect to mechanistic differences and quantitatively in order to determine the role of key factors for NHEJ and HR, respectively. The conclusions drawn from these studies allow for a better understanding of genome evolution and help identifying synergistic or antagonistic genetic interactions while supporting biotechnological applications for transiently modifying the plant DNA repair machinery in favor of targeted genome engineering.
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Affiliation(s)
- Carla Schmidt
- Botanical Institute, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Michael Pacher
- Botanical Institute, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Holger Puchta
- Botanical Institute, Karlsruhe Institute of Technology, Karlsruhe, Germany.
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18
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Samach A, Gurevich V, Avivi-Ragolsky N, Levy AA. The effects of AtRad52 over-expression on homologous recombination in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 95:30-40. [PMID: 29667244 DOI: 10.1111/tpj.13927] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2017] [Revised: 03/20/2018] [Accepted: 03/22/2018] [Indexed: 06/08/2023]
Abstract
AtRad52 homologs are involved in DNA recombination and repair, but their precise functions in different homologous recombination (HR) pathways or in gene-targeting have not been analyzed. In order to facilitate our analyses, we generated an AtRad52-1A variant that had a stronger nuclear localization than the native gene thanks to the removal of the transit peptide for mitochondrial localization and to the addition of a nuclear localization signal. Over-expression of this variant increased HR in the nucleus, compared with the native AtRad52-1A: it increased intra-chromosomal recombination and synthesis-dependent strand-annealing HR repair rates; but conversely, it repressed the single-strand annealing pathway. The effect of AtRad52-1A over-expression on gene-targeting was tested with and without the expression of small RNAs generated from an RNAi construct containing homology to the target and donor sequences. True gene-targeting events at the Arabidopsis Cruciferin locus were obtained only when combining AtRad52-1A over-expression and target/donor-specific RNAi. This suggests that sequence-specific small RNAs might be involved in AtRad52-1A-mediated HR.
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Affiliation(s)
- Aviva Samach
- Department of Plant and Environmental Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Vyacheslav Gurevich
- Department of Plant and Environmental Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Naomi Avivi-Ragolsky
- Department of Plant and Environmental Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Avraham A Levy
- Department of Plant and Environmental Sciences, The Weizmann Institute of Science, Rehovot, Israel
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19
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Dahan-Meir T, Filler-Hayut S, Melamed-Bessudo C, Bocobza S, Czosnek H, Aharoni A, Levy AA. Efficient in planta gene targeting in tomato using geminiviral replicons and the CRISPR/Cas9 system. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 95:5-16. [PMID: 29668111 DOI: 10.1111/tpj.13932] [Citation(s) in RCA: 125] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 03/19/2018] [Accepted: 03/22/2018] [Indexed: 05/21/2023]
Abstract
Current breeding relies mostly on random mutagenesis and recombination to generate novel genetic variation. However, targeted genome editing is becoming an increasingly important tool for precise plant breeding. Using the CRISPR-Cas system combined with the bean yellow dwarf virus rolling circle replicon, we optimized a method for targeted mutagenesis and gene replacement in tomato. The carotenoid isomerase (CRTISO) and phytoene synthase 1 (PSY1) genes from the carotenoid biosynthesis pathway were chosen as targets due to their easily detectable change of phenotype. We took advantage of the geminiviral replicon amplification as a means to provide a large amount of donor template for the repair of a CRISPR-Cas-induced DNA double-strand break (DSB) in the target gene, via homologous recombination (HR). Mutagenesis experiments, performed in the Micro-Tom variety, achieved precise modification of the CRTISO and PSY1 loci at an efficiency of up to 90%. In the gene targeting (GT) experiments, our target was a fast-neutron-induced crtiso allele that contained a 281-bp deletion. This deletion was repaired with the wild-type sequence through HR between the CRISPR-Cas-induced DSB in the crtiso target and the amplified donor in 25% of the plants transformed. This shows that efficient GT can be achieved in the absence of selection markers or reporters using a single and modular construct that is adaptable to other tomato targets and other crops.
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Affiliation(s)
- Tal Dahan-Meir
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Shdema Filler-Hayut
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Cathy Melamed-Bessudo
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Samuel Bocobza
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Henryk Czosnek
- The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem Rehovot, Rehovot, Israel
| | - Asaph Aharoni
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Avraham A Levy
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
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20
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Hahn F, Eisenhut M, Mantegazza O, Weber APM. Homology-Directed Repair of a Defective Glabrous Gene in Arabidopsis With Cas9-Based Gene Targeting. FRONTIERS IN PLANT SCIENCE 2018; 9:424. [PMID: 29675030 PMCID: PMC5895730 DOI: 10.3389/fpls.2018.00424] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 03/16/2018] [Indexed: 05/18/2023]
Abstract
The CRISPR/Cas9 system has emerged as a powerful tool for targeted genome editing in plants and beyond. Double-strand breaks induced by the Cas9 enzyme are repaired by the cell's own repair machinery either by the non-homologous end joining pathway or by homologous recombination (HR). While the first repair mechanism results in random mutations at the double-strand break site, HR uses the genetic information from a highly homologous repair template as blueprint for repair of the break. By offering an artificial repair template, this pathway can be exploited to introduce specific changes at a site of choice in the genome. However, frequencies of double-strand break repair by HR are very low. In this study, we compared two methods that have been reported to enhance frequencies of HR in plants. The first method boosts the repair template availability through the formation of viral replicons, the second method makes use of an in planta gene targeting (IPGT) approach. Additionally, we comparatively applied a nickase instead of a nuclease for target strand priming. To allow easy, visual detection of HR events, we aimed at restoring trichome formation in a glabrous Arabidopsis mutant by repairing a defective glabrous1 gene. Using this efficient visual marker, we were able to regenerate plants repaired by HR at frequencies of 0.12% using the IPGT approach, while both approaches using viral replicons did not yield any trichome-bearing plants.
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21
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22
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Baltes NJ, Gil-Humanes J, Voytas DF. Genome Engineering and Agriculture: Opportunities and Challenges. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2017; 149:1-26. [PMID: 28712492 PMCID: PMC8409219 DOI: 10.1016/bs.pmbts.2017.03.011] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In recent years, plant biotechnology has witnessed unprecedented technological change. Advances in high-throughput sequencing technologies have provided insight into the location and structure of functional elements within plant DNA. At the same time, improvements in genome engineering tools have enabled unprecedented control over genetic material. These technologies, combined with a growing understanding of plant systems biology, will irrevocably alter the way we create new crop varieties. As the first wave of genome-edited products emerge, we are just getting a glimpse of the immense opportunities the technology provides. We are also seeing its challenges and limitations. It is clear that genome editing will play an increased role in crop improvement and will help us to achieve food security in the coming decades; however, certain challenges and limitations must be overcome to realize the technology's full potential.
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23
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Horvath M, Steinbiss HH, Reiss B. Gene Targeting Without DSB Induction Is Inefficient in Barley. FRONTIERS IN PLANT SCIENCE 2017; 7:1973. [PMID: 28105032 PMCID: PMC5214849 DOI: 10.3389/fpls.2016.01973] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 12/13/2016] [Indexed: 05/29/2023]
Abstract
Double strand-break (DSB) induction allowed efficient gene targeting in barley (Hordeum vulgare), but little is known about efficiencies in its absence. To obtain such data, an assay system based on the acetolactate synthase (ALS) gene was established, a target gene which had been used previously in rice and Arabidopsis thaliana. Expression of recombinases RAD51 and RAD54 had been shown to improve gene targeting in A. thaliana and positive-negative (P-N) selection allows the routine production of targeted mutants without DSB induction in rice. We implemented these approaches in barley and analysed gene targeting with the ALS gene in wild type and RAD51 and RAD54 transgenic lines. In addition, P-N selection was tested. In contrast to the high gene targeting efficiencies obtained in the absence of DSB induction in A. thaliana or rice, not one single gene targeting event was obtained in barley. These data suggest that gene targeting efficiencies are very low in barley and can substantially differ between different plants, even at the same target locus. They also suggest that the amount of labour and time would become unreasonably high to use these methods as a tool in routine applications. This is particularly true since DSB induction offers efficient alternatives. Barley, unlike rice and A. thaliana has a large, complex genome, suggesting that genome size or complexity could be the reason for the low efficiencies. We discuss to what extent transformation methods, genome size or genome complexity could contribute to the striking differences in the gene targeting efficiencies between barley, rice and A. thaliana.
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Affiliation(s)
| | | | - Bernd Reiss
- Plant DNA Recombination Group, Max Planck Institute for Plant Breeding ResearchCologne, Germany
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24
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Kumar S, Worden A, Novak S, Lee R, Petolino JF. A trait stacking system via intra-genomic homologous recombination. PLANTA 2016; 244:1157-1166. [PMID: 27663725 DOI: 10.1007/s00425-016-2595-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 09/05/2016] [Indexed: 05/24/2023]
Abstract
MAIN CONCLUSION A gene targeting method has been developed, which allows the conversion of 'breeding stacks', containing unlinked transgenes into a 'molecular stack' and thereby circumventing the breeding challenges associated with transgene segregation. A gene targeting method has been developed for converting two unlinked trait loci into a single locus transgene stack. The method utilizes intra-genomic homologous recombination (IGHR) between stably integrated target and donor loci which share sequence homology and nuclease cleavage sites whereby the donor contains a promoterless herbicide resistance transgene. Upon crossing with a zinc finger nuclease (ZFN)-expressing plant, double-strand breaks (DSB) are created in both the stably integrated target and donor loci. DSBs flanking the donor locus result in intra-genomic mobilization of a promoterless selectable marker-containing donor sequence, which can be utilized as a template for homology-directed repair of a concomitant DSB at the target locus resulting in a functional selectable marker via nuclease-mediated cassette exchange (NMCE). The method was successfully demonstrated in maize using a glyphosate tolerance gene as a donor whereby up to 3.3 % of the resulting progeny embryos cultured on selection medium regenerated plants with the donor sequence integrated into the target locus. The process could be extended to multiple cycles of trait stacking by virtue of a unique intron sequence homology for NMCE between the target and the donor loci. This is the first report that describes NMCE via IGHR, thereby enabling trait stacking using conventional crossing.
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Affiliation(s)
- Sandeep Kumar
- Dow AgroSciences LLC, 9330 Zionsville Road, Indianapolis, IN, 46268, USA.
| | - Andrew Worden
- Dow AgroSciences LLC, 9330 Zionsville Road, Indianapolis, IN, 46268, USA
| | - Stephen Novak
- Dow AgroSciences LLC, 9330 Zionsville Road, Indianapolis, IN, 46268, USA
| | - Ryan Lee
- Dow AgroSciences LLC, 9330 Zionsville Road, Indianapolis, IN, 46268, USA
| | - Joseph F Petolino
- Dow AgroSciences LLC, 9330 Zionsville Road, Indianapolis, IN, 46268, USA
- Biotechnology Department, Ivy Tech Community College, 9301 East 59th Street, Indianapolis, IN, 46216, USA
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25
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Steinert J, Schiml S, Puchta H. Homology-based double-strand break-induced genome engineering in plants. PLANT CELL REPORTS 2016; 35:1429-38. [PMID: 27084537 DOI: 10.1007/s00299-016-1981-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 03/31/2016] [Indexed: 05/19/2023]
Abstract
This review summarises the recent progress in DSB-induced gene targeting by homologous recombination in plants. We are getting closer to efficiently inserting genes or precisely exchanging single amino acids. Although the basic features of double-strand break (DSB)-induced genome engineering were established more than 20 years ago, only in recent years has the technique come into the focus of plant biologists. Today, most scientists apply the recently discovered CRISPR/Cas system for inducing site-specific DSBs in genes of interest to obtain mutations by non-homologous end joining (NHEJ), which is the prevailing and often imprecise mechanism of DSB repair in somatic plant cells. However, predefined changes like the site-specific insertion of foreign genes or an exchange of single amino acids can be achieved by DSB-induced homologous recombination (HR). Although DSB induction drastically enhances the efficiency of HR, the efficiency is still about two orders of magnitude lower than that of NHEJ. Therefore, significant effort have been put forth to improve DSB-induced HR based technologies. This review summarises the previous studies as well as discusses the most recent developments in using the CRISPR/Cas system to improve these processes for plants.
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Affiliation(s)
- Jeannette Steinert
- Botanical Institute II, Karlsruhe Institute of Technology, POB 6980, 76049, Karlsruhe, Germany
| | - Simon Schiml
- Botanical Institute II, Karlsruhe Institute of Technology, POB 6980, 76049, Karlsruhe, Germany
| | - Holger Puchta
- Botanical Institute II, Karlsruhe Institute of Technology, POB 6980, 76049, Karlsruhe, Germany.
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26
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Petolino JF, Kumar S. Transgenic trait deployment using designed nucleases. PLANT BIOTECHNOLOGY JOURNAL 2016; 14:503-9. [PMID: 26332789 DOI: 10.1111/pbi.12457] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 07/08/2015] [Accepted: 07/16/2015] [Indexed: 05/09/2023]
Abstract
The demand for crops requiring increasingly complex combinations of transgenes poses unique challenges for transgenic trait deployment. Future value-adding traits such as those associated with crop performance are expected to involve multiple transgenes. Random integration of transgenes not only results in unpredictable expression and potential unwanted side effects but stacking multiple, randomly integrated, independently segregating transgenes creates breeding challenges during introgression and product development. Designed nucleases enable the creation of targeted DNA double-strand breaks at specified genomic locations whereby repair can result in targeted transgene integration leading to precise alterations in DNA sequences for plant genome editing, including the targeting of a transgene to a genomic locus that supports high-level and stable transgene expression without interfering with resident gene function. In addition, targeted DNA integration via designed nucleases allows for the addition of transgenes into previously integrated transgenic loci to create stacked products. The currently reported frequencies of independently generated transgenic events obtained with site-specific transgene integration without the aid of selection for targeting are very low. A modular, positive selection-based gene targeting strategy has been developed involving cassette exchange of selectable marker genes which allows for targeted events to be preferentially selected, over multiple cycles of sequential transformation. This, combined with the demonstration of intragenomic recombination following crossing of transgenic events that contain stably integrated donor and target DNA constructs with nuclease-expressing plants, points towards the future of trait stacking that is less dependent on high-efficiency transformation.
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27
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Weeks DP, Spalding MH, Yang B. Use of designer nucleases for targeted gene and genome editing in plants. PLANT BIOTECHNOLOGY JOURNAL 2016; 14:483-95. [PMID: 26261084 DOI: 10.1111/pbi.12448] [Citation(s) in RCA: 116] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Revised: 06/21/2015] [Accepted: 07/03/2015] [Indexed: 05/20/2023]
Abstract
The ability to efficiently inactivate or replace genes in model organisms allowed a rapid expansion of our understanding of many of the genetic, biochemical, molecular and cellular mechanisms that support life. With the advent of new techniques for manipulating genes and genomes that are applicable not only to single-celled organisms, but also to more complex organisms such as animals and plants, the speed with which scientists and biotechnologists can expand fundamental knowledge and apply that knowledge to improvements in medicine, industry and agriculture is set to expand in an exponential fashion. At the heart of these advancements will be the use of gene editing tools such as zinc finger nucleases, modified meganucleases, hybrid DNA/RNA oligonucleotides, TAL effector nucleases and modified CRISPR/Cas9. Each of these tools has the ability to precisely target one specific DNA sequence within a genome and (except for DNA/RNA oligonucleotides) to create a double-stranded DNA break. DNA repair to such breaks sometimes leads to gene knockouts or gene replacement by homologous recombination if exogenously supplied homologous DNA fragments are made available. Genome rearrangements are also possible to engineer. Creation and use of such genome rearrangements, gene knockouts and gene replacements by the plant science community is gaining significant momentum. To document some of this progress and to explore the technology's longer term potential, this review highlights present and future uses of designer nucleases to greatly expedite research with model plant systems and to engineer genes and genomes in major and minor crop species for enhanced food production.
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Affiliation(s)
- Donald P Weeks
- Department of Biochemistry, University of Nebraska, Lincoln, NE, USA
| | - Martin H Spalding
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, USA
| | - Bing Yang
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, USA
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28
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Sun Y, Li J, Xia L. Precise Genome Modification via Sequence-Specific Nucleases-Mediated Gene Targeting for Crop Improvement. FRONTIERS IN PLANT SCIENCE 2016; 7:1928. [PMID: 28066481 PMCID: PMC5167731 DOI: 10.3389/fpls.2016.01928] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 12/05/2016] [Indexed: 05/17/2023]
Abstract
Genome editing technologies enable precise modifications of DNA sequences in vivo and offer a great promise for harnessing plant genes in crop improvement. The precise manipulation of plant genomes relies on the induction of DNA double-strand breaks by sequence-specific nucleases (SSNs) to initiate DNA repair reactions that are based on either non-homologous end joining (NHEJ) or homology-directed repair (HDR). While complete knock-outs and loss-of-function mutations generated by NHEJ are very valuable in defining gene functions, their applications in crop improvement are somewhat limited because many agriculturally important traits are conferred by random point mutations or indels at specific loci in either the genes' encoding or promoter regions. Therefore, genome modification through SSNs-mediated HDR for gene targeting (GT) that enables either gene replacement or knock-in will provide an unprecedented ability to facilitate plant breeding by allowing introduction of precise point mutations and new gene functions, or integration of foreign genes at specific and desired "safe" harbor in a predefined manner. The emergence of three programmable SSNs, such as zinc finger nucleases, transcriptional activator-like effector nucleases, and the clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 9 (Cas9) systems has revolutionized genome modification in plants in a more controlled manner. However, while targeted mutagenesis is becoming routine in plants, the potential of GT technology has not been well realized for traits improvement in crops, mainly due to the fact that NHEJ predominates DNA repair process in somatic cells and competes with the HDR pathway, and thus HDR-mediated GT is a relative rare event in plants. Here, we review recent research findings mainly focusing on development and applications of precise GT in plants using three SSNs systems described above, and the potential mechanisms underlying HDR events in plant cells. We then address the challenges and propose future perspectives in order to facilitate the implementation of precise genome modification through SSNs-mediated GT for crop improvement in a global context.
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29
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Kumar S, Barone P, Smith M. Gene targeting and transgene stacking using intra genomic homologous recombination in plants. PLANT METHODS 2016; 12:11. [PMID: 26839580 PMCID: PMC4736180 DOI: 10.1186/s13007-016-0111-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 01/14/2016] [Indexed: 05/04/2023]
Abstract
Modern agriculture has created a demand for plant biotechnology products that provide durable resistance to insect pests, tolerance of herbicide applications for weed control, and agronomic traits tailored for specific geographies. These transgenic trait products require a modular and sequential multigene stacking platform that is supported by precise genome engineering technology. Designed nucleases have emerged as potent tools for creating targeted DNA double strand breaks (DSBs). Exogenously supplied donor DNA can repair the targeted DSB by a process known as gene targeting (GT), resulting in a desired modification of the target genome. The potential of GT technology has not been fully realized for trait deployment in agriculture, mainly because of inefficient transformation and plant regeneration systems in a majority of crop plants and genotypes. This challenge of transgene stacking in plants could be overcome by Intra-Genomic Homologous Recombination (IGHR) that converts independently segregating unlinked donor and target transgenic loci into a genetically linked molecular stack. The method requires stable integration of the donor DNA into the plant genome followed by intra-genomic mobilization. IGHR complements conventional breeding with genetic transformation and designed nucleases to provide a flexible transgene stacking and trait deployment platform.
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Affiliation(s)
- Sandeep Kumar
- Dow AgroSciences LLC, 9330 Zionsville Road, Indianapolis, IN 46286 USA
| | - Pierluigi Barone
- Dow AgroSciences LLC, 9330 Zionsville Road, Indianapolis, IN 46286 USA
| | - Michelle Smith
- Dow AgroSciences LLC, 9330 Zionsville Road, Indianapolis, IN 46286 USA
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Wang ZP, Xing HL, Dong L, Zhang HY, Han CY, Wang XC, Chen QJ. Egg cell-specific promoter-controlled CRISPR/Cas9 efficiently generates homozygous mutants for multiple target genes in Arabidopsis in a single generation. Genome Biol 2015. [PMID: 26193878 DOI: 10.1186/s13059-015-0715-710] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2023] Open
Abstract
Arabidopsis mutants produced by constitutive overexpression of the CRISPR/Cas9 genome editing system are usually mosaics in the T1 generation. In this study, we used egg cell-specific promoters to drive the expression of Cas9 and obtained non-mosaic T1 mutants for multiple target genes with high efficiency. Comparisons of 12 combinations of eight promoters and two terminators found that the efficiency of the egg cell-specific promoter-controlled CRISPR/Cas9 system depended on the presence of a suitable terminator, and the composite promoter generated by fusing two egg cell-specific promoters resulted in much higher efficiency of mutation in the T1 generation compared with the single promoters.
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Affiliation(s)
- Zhi-Ping Wang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
| | - Hui-Li Xing
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
| | - Li Dong
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
| | - Hai-Yan Zhang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
| | - Chun-Yan Han
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
| | - Xue-Chen Wang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
| | - Qi-Jun Chen
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
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Wang ZP, Xing HL, Dong L, Zhang HY, Han CY, Wang XC, Chen QJ. Egg cell-specific promoter-controlled CRISPR/Cas9 efficiently generates homozygous mutants for multiple target genes in Arabidopsis in a single generation. Genome Biol 2015; 16:144. [PMID: 26193878 PMCID: PMC4507317 DOI: 10.1186/s13059-015-0715-0] [Citation(s) in RCA: 633] [Impact Index Per Article: 70.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 07/02/2015] [Indexed: 11/26/2022] Open
Abstract
Arabidopsis mutants produced by constitutive overexpression of the CRISPR/Cas9 genome editing system are usually mosaics in the T1 generation. In this study, we used egg cell-specific promoters to drive the expression of Cas9 and obtained non-mosaic T1 mutants for multiple target genes with high efficiency. Comparisons of 12 combinations of eight promoters and two terminators found that the efficiency of the egg cell-specific promoter-controlled CRISPR/Cas9 system depended on the presence of a suitable terminator, and the composite promoter generated by fusing two egg cell-specific promoters resulted in much higher efficiency of mutation in the T1 generation compared with the single promoters.
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Affiliation(s)
- Zhi-Ping Wang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
| | - Hui-Li Xing
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
| | - Li Dong
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
| | - Hai-Yan Zhang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
| | - Chun-Yan Han
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
| | - Xue-Chen Wang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
| | - Qi-Jun Chen
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
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32
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Baltes NJ, Voytas DF. Enabling plant synthetic biology through genome engineering. Trends Biotechnol 2015; 33:120-31. [DOI: 10.1016/j.tibtech.2014.11.008] [Citation(s) in RCA: 109] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2014] [Revised: 10/28/2014] [Accepted: 11/19/2014] [Indexed: 02/09/2023]
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Johnson RA, Gurevich V, Filler S, Samach A, Levy AA. Comparative assessments of CRISPR-Cas nucleases' cleavage efficiency in planta. PLANT MOLECULAR BIOLOGY 2015; 87:143-56. [PMID: 25403732 DOI: 10.1007/s11103-014-0266-x] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2014] [Accepted: 11/12/2014] [Indexed: 05/21/2023]
Abstract
Custom-designed nucleases can enable precise plant genome editing by catalyzing DNA-breakage at specific targets to stimulate targeted mutagenesis or gene replacement. The CRISPR-Cas system, with its target-specifying RNA molecule to direct the Cas9 nuclease, is a recent addition to existing nucleases that bind and cleave the target through linked protein domains (e.g. TALENs and zinc-finger nucleases). We have conducted a comparative study of these different types of custom-designed nucleases and we have assessed various components of the CRISPR-Cas system. For this purpose, we have adapted our previously reported assay for cleavage-dependent luciferase gene correction in Nicotiana benthamiana leaves (Johnson et al. in Plant Mol Biol 82(3):207-221, 2013). We found that cleavage by CRISPR-Cas was more efficient than cleavage of the same target by TALENs. We also compared the cleavage efficiency of the Streptococcus pyogenes Cas9 protein based on expression using three different Cas9 gene variants. We found significant differences in cleavage efficiency between these variants, with human and Arabidopsis thaliana codon-optimized genes having the highest cleavage efficiencies. We compared the activity of 12 de novo-designed single synthetic guide RNA (sgRNA) constructs, and found their cleavage efficiency varied drastically when using the same Cas9 nuclease. Finally, we show that, for one of the targets tested with our assay, we could induce a germinally-transmitted deletion in a repeat array in A. thaliana. This work emphasizes the efficiency of the CRISPR-Cas system in plants. It also shows that further work is needed to be able to predict the optimal design of sgRNAs or Cas9 variants.
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Affiliation(s)
- Ross A Johnson
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel,
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34
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Petolino JF. Genome editing in plants via designed zinc finger nucleases. IN VITRO CELLULAR & DEVELOPMENTAL BIOLOGY. PLANT : JOURNAL OF THE TISSUE CULTURE ASSOCIATION 2015; 51:1-8. [PMID: 25774080 PMCID: PMC4352198 DOI: 10.1007/s11627-015-9663-3] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 01/07/2015] [Indexed: 05/19/2023]
Abstract
The ability to create DNA double-strand breaks (DSBs) at specified genomic locations, which then stimulate the cell's naturally occurring DNA repair processes, has introduced intriguing possibilities for genetic modification. Zinc finger nucleases (ZFNs) are designed restriction enzymes consisting of a nonspecific cleavage domain fused to sequence-specific DNA binding domains. ZFN-mediated DSB formation at endogenous genomic loci followed by error-prone non-homologous end joining (NHEJ) repair can result in gene-specific mutations via nucleotide base pair insertions or deletions. Similarly, specific DNA sequence modifications can be made by providing donor DNA templates homologous to sequences flanking the cleavage site via homology-directed repair (HDR). Targeted deletions of intervening DNA sequence can be obtained by ZFNs used to create concurrent DSBs. Site-specific transgene integration into ZFN-induced DSBs is possible via either NHEJ or HDR. Genome editing can be used to enhance our basic understanding of plant gene function as well as modify and improve crop plants. As with conventional plant transformation technology, the efficiency of genome editing is absolutely dependent on the ability to initiate, maintain, and regenerate plant cell and tissue cultures.
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Puchta H, Fauser F. Synthetic nucleases for genome engineering in plants: prospects for a bright future. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2014; 78:727-41. [PMID: 24112784 DOI: 10.1111/tpj.12338] [Citation(s) in RCA: 132] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Revised: 09/13/2013] [Accepted: 09/19/2013] [Indexed: 05/20/2023]
Abstract
By inducing double-strand breaks (DSB), it is possible to initiate DNA recombination. For a long time, it was not possible to use DSB induction for efficient genome engineering due to the lack of a means to target DSBs to specific sites. This limitation was overcome by development of modified meganucleases and synthetic DNA-binding domains. Domains derived from zinc-finger transcription factors or transcription activator-like effectors may be designed to recognize almost any DNA sequence. By fusing these domains to the endonuclease domains of a class II restriction enzyme, an active endonuclease dimer may be formed that introduces a site-specific DSB. Recent studies demonstrate that gene knockouts via non-homologous end joining or gene modification via homologous recombination are becoming routine in many plant species. By creating a single genomic DSB, complete knockout of a gene, sequence-specific integration of foreign DNA or subtle modification of individual amino acids in a specific protein domain may be achieved. The induction of two or more DSBs allows complex genomic rearrangements such as deletions, inversions or the exchange of chromosome arms. The potential for controlled genome engineering in plants is tremendous. The recently discovered RNA-based CRISPR/Cas system, a new tool to induce multiple DSBs, and sophisticated technical applications, such as the in planta gene targeting system, are further steps in this development. At present, the focus remains on engineering of single genes; in the future, engineering of whole genomes will become an option.
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Affiliation(s)
- Holger Puchta
- Botanical Institute II, Karlsruhe Institute of Technology, PO Box 6980, Karlsruhe, 76049, Germany
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36
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Fichtner F, Urrea Castellanos R, Ülker B. Precision genetic modifications: a new era in molecular biology and crop improvement. PLANTA 2014; 239:921-39. [PMID: 24510124 DOI: 10.1007/s00425-014-2029-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Accepted: 01/06/2014] [Indexed: 05/26/2023]
Abstract
Recently, the use of programmable DNA-binding proteins such as ZFP/ZFNs, TALE/TALENs and CRISPR/Cas has produced unprecedented advances in gene targeting and genome editing in prokaryotes and eukaryotes. These advances allow researchers to specifically alter genes, reprogram epigenetic marks, generate site-specific deletions and potentially cure diseases. Unlike previous methods, these precision genetic modification techniques (PGMs) are specific, efficient, easy to use and economical. Here we discuss the capabilities and pitfalls of PGMs and highlight the recent, exciting applications of PGMs in molecular biology and crop genetic engineering. Further improvement of the efficiency and precision of PGM techniques will enable researchers to precisely alter gene expression and biological/chemical pathways, probe gene function, modify epigenetic marks and improve crops by increasing yield, quality and tolerance to limiting biotic and abiotic stress conditions.
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Affiliation(s)
- Franziska Fichtner
- Plant Molecular Engineering Group, Institute of Cellular and Molecular Botany, University of Bonn, Kirschallee 1, 53115, Bonn, Germany
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37
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Bilichak A, Kovalchuk I. Manipulation of epigenetic factors and the DNA repair machinery for improving the frequency of plant transformation. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2014. [DOI: 10.1016/j.bcab.2013.08.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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38
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Lieberman-Lazarovich M, Melamed-Bessudo C, de Pater S, Levy AA. Epigenetic alterations at genomic loci modified by gene targeting in Arabidopsis thaliana. PLoS One 2013; 8:e85383. [PMID: 24386472 PMCID: PMC3873452 DOI: 10.1371/journal.pone.0085383] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Accepted: 11/26/2013] [Indexed: 12/20/2022] Open
Abstract
Gene Targeting (GT) is the integration of an introduced vector into a specific chromosomal site, via homologous recombination. It is considered an effective tool for precise genome editing, with far-reaching implications in biological research and biotechnology, and is widely used in mice, with the potential of becoming routine in many species. Nevertheless, the epigenetic status of the targeted allele remains largely unexplored. Using GT-modified lines of the model plant Arabidopsis thaliana, we show that the DNA methylation profile of the targeted locus is changed following GT. This effect is non-directional as methylation can be either completely lost, maintained with minor alterations or show instability in the generations subsequent to GT. As DNA methylation is known to be involved in several cellular processes, GT-related alterations may result in unexpected or even unnoticed perturbations. Our analysis shows that GT may be used as a new tool for generating epialleles, for example, to study the role of gene body methylation. In addition, the analysis of DNA methylation at the targeted locus may be utilized to investigate the mechanism of GT, many aspects of which are still unknown.
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Affiliation(s)
- Michal Lieberman-Lazarovich
- Department of Plant Biology, University of Geneva, Geneva, Switzerland
- Department of Plant Sciences, The Weizmann Institute of Science, Rehovot, Israel
- * E-mail:
| | | | - Sylvia de Pater
- Department of Molecular and Developmental Genetics, Institute of Biology, Leiden University, Leiden, The Netherlands
| | - Avraham A. Levy
- Department of Plant Sciences, The Weizmann Institute of Science, Rehovot, Israel
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39
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Christian M, Qi Y, Zhang Y, Voytas DF. Targeted mutagenesis of Arabidopsis thaliana using engineered TAL effector nucleases. G3 (BETHESDA, MD.) 2013; 3:1697-705. [PMID: 23979944 PMCID: PMC3789794 DOI: 10.1534/g3.113.007104] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Accepted: 07/29/2013] [Indexed: 11/18/2022]
Abstract
Custom TAL effector nucleases (TALENs) are increasingly used as reagents to manipulate genomes in vivo. Here, we used TALENs to modify the genome of the model plant, Arabidopsis thaliana. We engineered seven TALENs targeting five Arabidopsis genes, namely ADH1, TT4, MAPKKK1, DSK2B, and NATA2. In pooled seedlings expressing the TALENs, we observed somatic mutagenesis frequencies ranging from 2-15% at the intended targets for all seven TALENs. Somatic mutagenesis frequencies as high as 41-73% were observed in individual transgenic plant lines expressing the TALENs. Additionally, a TALEN pair targeting a tandemly duplicated gene induced a 4.4-kb deletion in somatic cells. For the most active TALEN pairs, namely those targeting ADH1 and NATA2, we found that TALEN-induced mutations were transmitted to the next generation at frequencies of 1.5-12%. Our work demonstrates that TALENs are useful reagents for achieving targeted mutagenesis in this important plant model.
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Affiliation(s)
- Michelle Christian
- Department of Genetics, Cell Biology, and Development and Center for Genome Engineering, University of Minnesota, Minneapolis, Minnesota 55455
| | - Yiping Qi
- Department of Genetics, Cell Biology, and Development and Center for Genome Engineering, University of Minnesota, Minneapolis, Minnesota 55455
| | - Yong Zhang
- Department of Biotechnology, School of Life Sciences and Technology, University of Electronic Science and Technology of China, Chendu 610054, China
| | - Daniel F. Voytas
- Department of Genetics, Cell Biology, and Development and Center for Genome Engineering, University of Minnesota, Minneapolis, Minnesota 55455
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40
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Johnson RA, Gurevich V, Levy AA. A rapid assay to quantify the cleavage efficiency of custom-designed nucleases in planta. PLANT MOLECULAR BIOLOGY 2013; 82:207-21. [PMID: 23625357 DOI: 10.1007/s11103-013-0052-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Accepted: 03/23/2013] [Indexed: 06/02/2023]
Abstract
Custom-designed nucleases are a promising technology for genome editing through the catalysis of double-strand DNA breaks within target loci and subsequent repair by the host cell, which can result in targeted mutagenesis or gene replacement. Implementing this new technology requires a rapid means to determine the cleavage efficiency of these custom-designed proteins in planta. Here we present such an assay that is based on cleavage-dependent luciferase gene correction as part of a transient dual-luciferase(®) reporter (Promega) expression system. This assay consists of co-infiltrating Nicotiana benthamiana leaves with two Agrobacterium tumefaciens strains: one contains the target sequence embedded within a luciferase reporter gene and the second strain contains the custom-designed nuclease gene(s). We compared repair following site-specific nuclease digestion through non-homologous DNA end-joining, as opposed to single strand DNA annealing, as a means to restore an out-of-frame luciferase gene cleavage-reporter construct. We show, using luminometer measurements and bioluminescence imaging, that the assay for non-homologous end-joining is sensitive, quantitative, reproducible and rapid in estimating custom-designed nucleases' cleavage efficiency. We detected cleavage by two out of three transcription activator-like effector nucleases that we custom-designed for targets in the Arabidopsis CRUCIFERIN3 gene, and we compared with the well-established 'QQR' zinc-finger nuclease. The assay we report requires only standard equipment and basic plant molecular biology techniques, and it can be carried out within a few days. Different types of custom-designed nucleases can be preliminarily tested in our assay system before their downstream application in plant genome editing.
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Affiliation(s)
- Ross A Johnson
- Department of Plant Sciences, the Weizmann Institute of Science, P.O. Box 26, 76100 Rehovot, Israel.
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41
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de Pater S, Pinas JE, Hooykaas PJJ, van der Zaal BJ. ZFN-mediated gene targeting of the Arabidopsis protoporphyrinogen oxidase gene through Agrobacterium-mediated floral dip transformation. PLANT BIOTECHNOLOGY JOURNAL 2013; 11:510-5. [PMID: 23279135 PMCID: PMC3719044 DOI: 10.1111/pbi.12040] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Revised: 11/16/2012] [Accepted: 11/28/2012] [Indexed: 05/20/2023]
Abstract
Previously, we showed that ZFN-mediated induction of double-strand breaks (DSBs) at the intended recombination site enhanced the frequency of gene targeting (GT) at an artificial target locus using Agrobacterium-mediated floral dip transformation. Here, we designed zinc finger nucleases (ZFNs) for induction of DSBs in the natural protoporphyrinogen oxidase (PPO) gene, which can be conveniently utilized for GT experiments. Wild-type Arabidopsis plants and plants expressing the ZFNs were transformed via floral dip transformation with a repair T-DNA with an incomplete PPO gene, missing the 5' coding region but containing two mutations rendering the enzyme insensitive to the herbicide butafenacil as well as an extra KpnI site for molecular analysis of GT events. Selection on butafenacil yielded 2 GT events for the wild type with a frequency of 0.8 × 10⁻³ per transformation event and 8 GT events for the ZFNs expressing plant line with a frequency of 3.1 × 10⁻³ per transformation event. Molecular analysis using PCR and Southern blot analysis showed that 9 of the GT events were so-called true GT events, repaired via homologous recombination (HR) at the 5' and the 3' end of the gene. One plant line contained a PPO gene repaired only at the 5' end via HR. Most plant lines contained extra randomly integrated T-DNA copies. Two plant lines did not contain extra T-DNAs, and the repaired PPO genes in these lines were transmitted to the next generation in a Mendelian fashion.
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Affiliation(s)
- Sylvia de Pater
- Department of Molecular and Developmental Genetics, Institute of Biology, Leiden University, Leiden, The Netherlands.
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42
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Podevin N, Davies HV, Hartung F, Nogué F, Casacuberta JM. Site-directed nucleases: a paradigm shift in predictable, knowledge-based plant breeding. Trends Biotechnol 2013; 31:375-83. [PMID: 23601269 DOI: 10.1016/j.tibtech.2013.03.004] [Citation(s) in RCA: 114] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Revised: 03/11/2013] [Accepted: 03/11/2013] [Indexed: 12/17/2022]
Abstract
Conventional plant breeding exploits existing genetic variability and introduces new variability by mutagenesis. This has proven highly successful in securing food supplies for an ever-growing human population. The use of genetically modified plants is a complementary approach but all plant breeding techniques have limitations. Here, we discuss how the recent evolution of targeted mutagenesis and DNA insertion techniques based on tailor-made site-directed nucleases (SDNs) provides opportunities to overcome such limitations. Plant breeding companies are exploiting SDNs to develop a new generation of crops with new and improved traits. Nevertheless, some technical limitations as well as significant uncertainties on the regulatory status of SDNs may challenge their use for commercial plant breeding.
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Affiliation(s)
- Nancy Podevin
- The European Food Safety Authority-EFSA, Via Carlo Magno 1A, Parma, Italy
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Abstract
Recent advances in genome engineering provide newfound control over a plant's genetic material. It is now possible for most bench scientists to alter DNA in living plant cells in a variety of ways, including introducing specific nucleotide substitutions in a gene that change a protein's amino acid sequence, deleting genes or chromosomal segments, and inserting foreign DNA at precise genomic locations. Such targeted DNA sequence modifications are enabled by sequence-specific nucleases that create double-strand breaks in the genomic loci to be altered. The repair of the breaks, through either homologous recombination or nonhomologous end joining, can be controlled to achieve the desired sequence modification. Genome engineering promises to advance basic plant research by linking DNA sequences to biological function. Further, genome engineering will enable plants' biosynthetic capacity to be harnessed to produce the many agricultural products required by an expanding world population.
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Affiliation(s)
- Daniel F Voytas
- Department of Genetics, Cell Biology, and Development and Center for Genome Engineering, University of Minnesota, Minneapolis, MN 55455, USA.
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44
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Tzfira T, Weinthal D, Marton I, Zeevi V, Zuker A, Vainstein A. Genome modifications in plant cells by custom-made restriction enzymes. PLANT BIOTECHNOLOGY JOURNAL 2012; 10:373-89. [PMID: 22469004 DOI: 10.1111/j.1467-7652.2011.00672.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Genome editing, i.e. the ability to mutagenize, insert, delete and replace sequences, in living cells is a powerful and highly desirable method that could potentially revolutionize plant basic research and applied biotechnology. Indeed, various research groups from academia and industry are in a race to devise methods and develop tools that will enable not only site-specific mutagenesis but also controlled foreign DNA integration and replacement of native and transgene sequences by foreign DNA, in living plant cells. In recent years, much of the progress seen in gene targeting in plant cells has been attributed to the development of zinc finger nucleases and other novel restriction enzymes for use as molecular DNA scissors. The induction of double-strand breaks at specific genomic locations by zinc finger nucleases and other novel restriction enzymes results in a wide variety of genetic changes, which range from gene addition to the replacement, deletion and site-specific mutagenesis of endogenous and heterologous genes in living plant cells. In this review, we discuss the principles and tools for restriction enzyme-mediated gene targeting in plant cells, as well as their current and prospective use for gene targeting in model and crop plants.
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Affiliation(s)
- Tzvi Tzfira
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel.
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45
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Abstract
The development of designed site-specific endonucleases boosted the establishment of gene targeting (GT) techniques in a row of different species. However, the methods described in plants require a highly efficient transformation and regeneration procedure and, therefore, can be applied to very few species. Here, we describe a highly efficient GT system that is suitable for all transformable plants regardless of transformation efficiency. Efficient in planta GT was achieved in Arabidopsis thaliana by expression of a site-specific endonuclease that not only cuts within the target but also the chromosomal transgenic donor, leading to an excised targeting vector. Progeny clonal for the targeted allele could be obtained directly by harvesting seeds. Targeted events could be identified up to approximately once per 100 seeds depending on the target donor combination. Molecular analysis demonstrated that, in almost all events, homologous recombination occurred at both ends of the break. No ectopic integration of the GT vector was found.
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