scholarly journals Highly efficient multiplex genome editing in dicot plants using improved CRISPR/Cas systems

2022 ◽  
Author(s):  
Bingjie Li ◽  
Yun Shang ◽  
Lixianqiu Wang ◽  
Jing Lv ◽  
Fengjiao Wang ◽  
...  

CRISPR/Cas9-mediated gene editing provides a powerful tool for dissecting gene function and improving important traits in crops. However, there are still persisting challenges to obtain high homozygous/bi-allelic (ho/bi) mutations in dicot plants. Here, we develop an improved CRISPR/Cas9 system harboring a calreticulin-like gene promoter, which can boost targeted mutations in dicots. Additionally, the pDC45_dsg construct, combining a 35Spro-tRNA_sgRNA-EU unit and PCE8pro-controlled Cas9, can achieve more than 80.0% ho/bi mutations at target sites in allotetraploid tobacco. We construct pDC45_Fast system that can simultaneously fulfill gene editing and shorten the life span of T0 generation tobacco and tomato. This study provides new tools for improving targeted gene mutagenesis in dicots, and makes manipulations of genes in Solanum more feasible.

2018 ◽  
Vol 19 (10) ◽  
pp. 3000 ◽  
Author(s):  
Shouhong Zhu ◽  
Xiuli Yu ◽  
Yanjun Li ◽  
Yuqiang Sun ◽  
Qianhao Zhu ◽  
...  

The clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9) gene editing system has been shown to be able to induce highly efficient mutagenesis in the targeted DNA of many plants, including cotton, and has become an important tool for investigation of gene function and crop improvement. Here, we developed a simple and easy to operate CRISPR/Cas9 system and demonstrated its high editing efficiency in cotton by targeting-ALARP, a gene encoding alanine-rich protein that is preferentially expressed in cotton fibers. Based on sequence analysis of the target site in the 10 transgenic cottons containing CRISPR/Cas9, we found that the mutation frequencies of GhALARP-A and GhALARP-D target sites were 71.4–100% and 92.9–100%, respectively. The most common editing event was deletion, but deletion together with large insertion was also observed. Mosaic mutation editing events were detected in most transgenic plants. No off-target mutation event was detected in any the 15 predicted sites analyzed. This study provided mutants for further study of the function of GhALARP in cotton fiber development. Our results further demonstrated the feasibility of use of CRISPR/Cas9 as a targeted mutagenesis tool in cotton, and provided an efficient tool for targeted mutagenesis and functional genomics in cotton.


2020 ◽  
Author(s):  
Keke Xia ◽  
Dengwei Zhang ◽  
Guangyu Liu ◽  
Xiaojing Xu ◽  
Yong Yang ◽  
...  

AbstractPhalaenopsis orchids are popular ornamental plants worldwide. The application of the efficient multiplex genome editing tools in Phalaenopsis, will greatly accelerate the development of orchid gene function and breeding research. In this study, we establish a fast and convenient Phalaenopsis protoplast platform for the identification of functional genome editing tools. Two multiplex genome editing tools, PTG-Cas9 (PTG, polycistronic tRNA gRNA) system and PTGm-Cas9 (PTG-Cas9 system with modified sgRNA structure) system are designed to edit PDS gene of commercial Phalaenopsis ST166 at four target sites. We find that both PTG-Cas9 and PTGm-Cas9 system are functional in Phalaenopsis, and the PTGm-Cas9 system with modified sgRNA has a higher editing efficiency than PTG-Cas9 system. Further, we design another multiplex genome editing tool, termed as DPII-Cpf1 system (dual Pol II promoter to drive the expression of Cpf1 endonuclease and crRNA), to edit PDS gene of Phalaenopsis at four target sites likewise. All the four targets are efficiently edited by DPII-Cpf1 system, and the total mutation rate is about 3 times higher than that of PTGm-Cas9 system. Taken together, using the Phalaenopsis protoplast platform, we successfully establish two efficient multiplex genome editing tools for Phalaenopsis research, PTGm-Cas9 and DPII-Cpf1. The multiplex genome editing tools established in this study have great application potentials in efficiently constructing large-scale knockout mutant libraries of orchid and speeding up orchid precise breeding.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Surbhi Jain ◽  
Saurabh Shukla ◽  
Che Yang ◽  
Meng Zhang ◽  
Zia Fatma ◽  
...  

AbstractGenome editing critically relies on selective recognition of target sites. However, despite recent progress, the underlying search mechanism of genome-editing proteins is not fully understood in the context of cellular chromatin environments. Here, we use single-molecule imaging in live cells to directly study the behavior of CRISPR/Cas9 and TALEN. Our single-molecule imaging of genome-editing proteins reveals that Cas9 is less efficient in heterochromatin than TALEN because Cas9 becomes encumbered by local searches on non-specific sites in these regions. We find up to a fivefold increase in editing efficiency for TALEN compared to Cas9 in heterochromatin regions. Overall, our results show that Cas9 and TALEN use a combination of 3-D and local searches to identify target sites, and the nanoscopic granularity of local search determines the editing outcomes of the genome-editing proteins. Taken together, our results suggest that TALEN is a more efficient gene-editing tool than Cas9 for applications in heterochromatin.


2021 ◽  
Vol 12 ◽  
Author(s):  
Yi An ◽  
Ya Geng ◽  
Junguang Yao ◽  
Chun Wang ◽  
Juan Du

Gene editing technology in woody plants has great potential for understanding gene function, and altering traits affecting economically and ecologically important traits. Gene editing applications in woody species require a high genome editing efficiency due to the difficulty during transformation and complexities resulting from gene redundancy. In this study, we used poplar 84K (Populus alba × P. glandulosa), which is a model hybrid for studying wood formation and growth. We developed a new CRISPR/Cas9 system to edit multiple genes simultaneously. Using this system, we successfully knocked out multiple targets of the PHYTOENE DESATURASE 8 in poplar. We found the mutation rate of our CRISPR/Cas9 system is higher (67.5%) than existing reports in woody trees. We further improved the mutation rate up to 75% at editing sites through the usage of the mannopine synthase (MAS) promoter to drive Cas9. The MAS-CRISPR/Cas9 is an improved genome-editing tool for woody plants with a higher efficiency and a higher mutation rate than currently available technologies.


Viruses ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 779
Author(s):  
Man Teng ◽  
Yongxiu Yao ◽  
Venugopal Nair ◽  
Jun Luo

In recent years, the CRISPR/Cas9-based gene-editing techniques have been well developed and applied widely in several aspects of research in the biological sciences, in many species, including humans, animals, plants, and even in viruses. Modification of the viral genome is crucial for revealing gene function, virus pathogenesis, gene therapy, genetic engineering, and vaccine development. Herein, we have provided a brief review of the different technologies for the modification of the viral genomes. Particularly, we have focused on the recently developed CRISPR/Cas9-based gene-editing system, detailing its origin, functional principles, and touching on its latest achievements in virology research and applications in vaccine development, especially in large DNA viruses of humans and animals. Future prospects of CRISPR/Cas9-based gene-editing technology in virology research, including the potential shortcomings, are also discussed.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Xianhang Wang ◽  
Mingxing Tu ◽  
Ya Wang ◽  
Wuchen Yin ◽  
Yu Zhang ◽  
...  

AbstractThe CRISPR (clustered regularly interspaced short palindromic repeats)-associated protein 9 (Cas9) system is a powerful tool for targeted genome editing, with applications that include plant biotechnology and functional genomics research. However, the specificity of Cas9 targeting is poorly investigated in many plant species, including fruit trees. To assess the off-target mutation rate in grapevine (Vitis vinifera), we performed whole-genome sequencing (WGS) of seven Cas9-edited grapevine plants in which one of two genes was targeted by CRISPR/Cas9 and three wild-type (WT) plants. In total, we identified between 202,008 and 272,397 single nucleotide polymorphisms (SNPs) and between 26,391 and 55,414 insertions/deletions (indels) in the seven Cas9-edited grapevine plants compared with the three WT plants. Subsequently, 3272 potential off-target sites were selected for further analysis. Only one off-target indel mutation was identified from the WGS data and validated by Sanger sequencing. In addition, we found 243 newly generated off-target sites caused by genetic variants between the Thompson Seedless cultivar and the grape reference genome (PN40024) but no true off-target mutations. In conclusion, we observed high specificity of CRISPR/Cas9 for genome editing of grapevine.


2021 ◽  
Vol 7 (7) ◽  
pp. 505
Author(s):  
Ping Zhang ◽  
Yu Wang ◽  
Chenxi Li ◽  
Xiaoyu Ma ◽  
Lan Ma ◽  
...  

Cryptococcus neoformans and Cryptococcus deneoformans are opportunistic fungal pathogens found worldwide that are utilized to reveal mechanisms of fungal pathogenesis. However, their low homologous recombination frequency has greatly encumbered genetic studies. In preliminary work, we described a ‘suicide’ CRISPR-Cas9 system for use in the efficient gene editing of C. deneoformans, but this has not yet been used in the C. neoformans strain. The procedures involved in constructing vectors are time-consuming, whether they involve restriction enzyme-based cloning of donor DNA or the introduction of a target sequence into the gRNA expression cassette via overlap PCR, as are sophisticated, thus impeding their widespread application. Here, we report the optimized and simplified construction method for all-in-one CRISPR-Cas9 vectors that can be used in C. neoformans and C. deneoformans strains respectively, named pNK003 (Genbank: MW938321) and pRH003 (Genbank: KX977486). Taking several gene manipulations as examples, we also demonstrate the accuracy and efficiency of the new simplified all-in-one CRISPR-Cas9 genome editing tools in both Serotype A and Serotype D strains, as well as their ability to eliminate Cas9 and gDNA cassettes after gene editing. We anticipate that the availability of new vectors that can simplify and streamline the technical steps for all-in-one CRISPR-Cas9 construction could accelerate genetic studies of the Cryptococcus species.


2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Menglong Chen ◽  
Hui Shi ◽  
Shixue Gou ◽  
Xiaomin Wang ◽  
Lei Li ◽  
...  

Abstract Background Mutations in the DMD gene encoding dystrophin—a critical structural element in muscle cells—cause Duchenne muscular dystrophy (DMD), which is the most common fatal genetic disease. Clustered regularly interspaced short palindromic repeat (CRISPR)-mediated gene editing is a promising strategy for permanently curing DMD. Methods In this study, we developed a novel strategy for reframing DMD mutations via CRISPR-mediated large-scale excision of exons 46–54. We compared this approach with other DMD rescue strategies by using DMD patient-derived primary muscle-derived stem cells (DMD-MDSCs). Furthermore, a patient-derived xenograft (PDX) DMD mouse model was established by transplanting DMD-MDSCs into immunodeficient mice. CRISPR gene editing components were intramuscularly delivered into the mouse model by adeno-associated virus vectors. Results Results demonstrated that the large-scale excision of mutant DMD exons showed high efficiency in restoring dystrophin protein expression. We also confirmed that CRISPR from Prevotella and Francisella 1(Cas12a)-mediated genome editing could correct DMD mutation with the same efficiency as CRISPR-associated protein 9 (Cas9). In addition, more than 10% human DMD muscle fibers expressed dystrophin in the PDX DMD mouse model after treated by the large-scale excision strategies. The restored dystrophin in vivo was functional as demonstrated by the expression of the dystrophin glycoprotein complex member β-dystroglycan. Conclusions We demonstrated that the clinically relevant CRISPR/Cas9 could restore dystrophin in human muscle cells in vivo in the PDX DMD mouse model. This study demonstrated an approach for the application of gene therapy to other genetic diseases.


2019 ◽  
Vol 20 (15) ◽  
pp. 3623 ◽  
Author(s):  
Tobias Bruegmann ◽  
Khira Deecke ◽  
Matthias Fladung

CRISPR/Cas9 has become one of the most promising techniques for genome editing in plants and works very well in poplars with an Agrobacterium-mediated transformation system. We selected twelve genes, including SOC1, FUL, and their paralogous genes, four NFP-like genes and TOZ19 for three different research topics. The gRNAs were designed for editing, and, together with a constitutively expressed Cas9 nuclease, transferred either into the poplar hybrid Populus × canescens or into P. tremula. The regenerated lines showed different types of editing and revealed several homozygous editing events which are of special interest in perennial species because of limited back-cross ability. Through a time series, we could show that despite the constitutive expression of the Cas9 nuclease, no secondary editing of the target region occurred. Thus, constitutive Cas9 expression does not seem to pose any risk to additional editing events. Based on various criteria, we obtained evidence for a relationship between the structure of gRNA and the efficiency of gene editing. In particular, the GC content, purine residues in the gRNA end, and the free accessibility of the seed region seemed to be highly important for genome editing in poplars. Based on our findings on nine different poplar genes, efficient gRNAs can be designed for future efficient editing applications in poplars.


mSphere ◽  
2017 ◽  
Vol 2 (2) ◽  
Author(s):  
Namkha Nguyen ◽  
Morgan M. F. Quail ◽  
Aaron D. Hernday

ABSTRACT Candida albicans is the most common fungal pathogen of humans. Historically, molecular genetic analysis of this important pathogen has been hampered by the lack of stable plasmids or meiotic cell division, limited selectable markers, and inefficient methods for generating gene knockouts. The recent development of clustered regularly interspaced short palindromic repeat(s) (CRISPR)-based tools for use with C. albicans has opened the door to more efficient genome editing; however, previously reported systems have specific limitations. We report the development of an optimized CRISPR-based genome editing system for use with C. albicans. Our system is highly efficient, does not require molecular cloning, does not leave permanent markers in the genome, and supports rapid, precise genome editing in C. albicans. We also demonstrate the utility of our system for generating two independent homozygous gene knockouts in a single transformation and present a method for generating homozygous wild-type gene addbacks at the native locus. Furthermore, each step of our protocol is compatible with high-throughput strain engineering approaches, thus opening the door to the generation of a complete C. albicans gene knockout library. IMPORTANCE Candida albicans is the major fungal pathogen of humans and is the subject of intense biomedical and discovery research. Until recently, the pace of research in this field has been hampered by the lack of efficient methods for genome editing. We report the development of a highly efficient and flexible genome editing system for use with C. albicans. This system improves upon previously published C. albicans CRISPR systems and enables rapid, precise genome editing without the use of permanent markers. This new tool kit promises to expedite the pace of research on this important fungal pathogen.


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