Genome editing using CRISPR/Cas9–targeted mutagenesis: An opportunity for yield improvements of crop plants grown under environmental stresses

Increasing agricultural productivity via modern breeding strategies is of prime interest to attain global food security. An array of biotic and abiotic stressors affect productivity as well as the quality of crop plants, and it is a primary need to develop crops with improved adaptability, high productivity, and resilience against these biotic/abiotic stressors. Conventional approaches to genetic engineering involve tedious procedures. State-of-the-art OMICS approaches reinforced with next-generation sequencing and the latest developments in genome editing tools have paved the way for targeted mutagenesis, opening new horizons for precise genome engineering. Various genome editing tools such as transcription activator-like effector nucleases (TALENs), zinc-finger nucleases (ZFNs), and meganucleases (MNs) have enabled plant scientists to manipulate desired genes in crop plants. However, these approaches are expensive and laborious involving complex procedures for successful editing. Conversely, CRISPR/Cas9 is an entrancing, easy-to-design, cost-effective, and versatile tool for precise and efficient plant genome editing. In recent years, the CRISPR/Cas9 system has emerged as a powerful tool for targeted mutagenesis, including single base substitution, multiplex gene editing, gene knockouts, and regulation of gene transcription in plants. Thus, CRISPR/Cas9-based genome editing has demonstrated great potential for crop improvement but regulation of genome-edited crops is still in its infancy. Here, we extensively reviewed the availability of CRISPR/Cas9 genome editing tools for plant biotechnologists to target desired genes and its vast applications in crop breeding research.

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Knock-in and precise nucleotide substitution using near-PAMless engineered Cas9 variants in Dictyostelium discoideum

Scientific Reports ◽

10.1038/s41598-021-89546-0 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Yuu Asano ◽

Kensuke Yamashita ◽

Aoi Hasegawa ◽

Takanori Ogasawara ◽

Hoshie Iriki ◽

...

Keyword(s):

Genome Editing ◽

Dictyostelium Discoideum ◽

Streptococcus Pyogenes ◽

Nucleotide Substitution ◽

Point Mutations ◽

Targeted Mutagenesis ◽

Single Amino Acid ◽

Specific Gene ◽

Knock Out ◽

Protospacer Adjacent Motif

AbstractThe powerful genome editing tool Streptococcus pyogenes Cas9 (SpCas9) requires the trinucleotide NGG as a protospacer adjacent motif (PAM). The PAM requirement is limitation for precise genome editing such as single amino-acid substitutions and knock-ins at specific genomic loci since it occurs in narrow editing window. Recently, SpCas9 variants (i.e., xCas9 3.7, SpCas9-NG, and SpRY) were developed that recognise the NG dinucleotide or almost any other PAM sequences in human cell lines. In this study, we evaluated these variants in Dictyostelium discoideum. In the context of targeted mutagenesis at an NG PAM site, we found that SpCas9-NG and SpRY were more efficient than xCas9 3.7. In the context of NA, NT, NG, and NC PAM sites, the editing efficiency of SpRY was approximately 60% at NR (R = A and G) but less than 22% at NY (Y = T and C). We successfully used SpRY to generate knock-ins at specific gene loci using donor DNA flanked by 60 bp homology arms. In addition, we achieved point mutations with efficiencies as high as 97.7%. This work provides tools that will significantly expand the gene loci that can be targeted for knock-out, knock-in, and precise point mutation in D. discoideum.

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First genome edited poinsettias: targeted mutagenesis of flavonoid 3′-hydroxylase using CRISPR/Cas9 results in a colour shift

Plant Cell Tissue and Organ Culture (PCTOC) ◽

10.1007/s11240-021-02103-5 ◽

2021 ◽

Author(s):

Daria Nitarska ◽

Robert Boehm ◽

Thomas Debener ◽

Rares Calin Lucaciu ◽

Heidi Halbwirth

Keyword(s):

Transgenic Plants ◽

Genome Editing ◽

Ornamental Plants ◽

Targeted Mutagenesis ◽

Cloning And Expression ◽

Euphorbia Pulcherrima ◽

Loss Of Function ◽

Wild Type ◽

Promising Tool ◽

Reddish Orange

AbstractThe CRISPR/Cas9 system is a remarkably promising tool for targeted gene mutagenesis, and becoming ever more popular for modification of ornamental plants. In this study we performed the knockout of flavonoid 3′-hydroxylase (F3′H) with application of CRISPR/Cas9 in the red flowering poinsettia (Euphorbia pulcherrima) cultivar ‘Christmas Eve’, in order to obtain plants with orange bract colour, which accumulate prevalently pelargonidin. F3′H is an enzyme that is necessary for formation of cyanidin type anthocyanins, which are responsible for the red colour of poinsettia bracts. Even though F3′H was not completely inactivated, the bract colour of transgenic plants changed from vivid red (RHS 45B) to vivid reddish orange (RHS 33A), and cyanidin levels decreased significantly compared with the wild type. In the genetically modified plants, an increased ratio of pelargonidin to cyanidin was observed. By cloning and expression of mutated proteins, the lack of F3′H activity was confirmed. This confirms that a loss of function mutation in the poinsettia F3′H gene is sufficient for obtaining poinsettia with orange bract colour. This is the first report of successful use of CRISPR/Cas9 for genome editing in poinsettia.

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CRISPR/Cas9-mediated targeted mutagenesis in Japanese cedar (Cryptomeria japonica D. Don)

Scientific Reports ◽

10.1038/s41598-021-95547-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Yoshihiko Nanasato ◽

Masafumi Mikami ◽

Norihiro Futamura ◽

Masaki Endo ◽

Mitsuru Nishiguchi ◽

...

Keyword(s):

Genome Editing ◽

Cryptomeria Japonica ◽

Fluorescent Protein ◽

Japanese Cedar ◽

Targeted Mutagenesis ◽

Embryogenic Tissue ◽

Breeding Period ◽

Single Mutation ◽

Knock Out ◽

Guide Rna

AbstractCryptomeria japonica (Japanese cedar or sugi) is one of the most important coniferous tree species in Japan and breeding programs for this species have been launched since 1950s. Genome editing technology can be used to shorten the breeding period. In this study, we performed targeted mutagenesis using the CRISPR/Cas9 system in C. japonica. First, the CRISPR/Cas9 system was tested using green fluorescent protein (GFP)-expressing transgenic embryogenic tissue lines. Knock-out efficiency of GFP ranged from 3.1 to 41.4% depending on U6 promoters and target sequences. The GFP knock-out region was mottled in many lines, indicating genome editing in individual cells. However, in 101 of 102 mutated individuals (> 99%) from 6 GFP knock-out lines, embryos had a single mutation pattern. Next, we knocked out the endogenous C. japonica magnesium chelatase subunit I (CjChlI) gene using two guide RNA targets. Green, pale green, and albino phenotypes were obtained in the gene-edited cell lines. Sequence analysis revealed random deletions, insertions, and replacements in the target region. Thus, targeted mutagenesis using the CRISPR/Cas9 system can be used to modify the C. japonica genome.

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Genomics-Based Analyses of Environmental Stresses in Crop Plants

Approaches to Plant Stress and their Management ◽

10.1007/978-81-322-1620-9_22 ◽

2013 ◽

pp. 383-393

Author(s):

Meenakumari Muthuramalingam ◽

Yong-Fang Li ◽

Ramamurthy Mahalingam

Keyword(s):

Environmental Stresses ◽

Crop Plants

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Improving Precise CRISPR Genome Editing by Small Molecules: Is there a Magic Potion?

Cells ◽

10.3390/cells9051318 ◽

2020 ◽

Vol 9 (5) ◽

pp. 1318 ◽

Cited By ~ 2

Author(s):

Nadja Bischoff ◽

Sandra Wimberger ◽

Marcello Maresca ◽

Cord Brakebusch

Keyword(s):

Gene Therapy ◽

Dna Repair ◽

Animal Models ◽

Molecular Biology ◽

Small Molecules ◽

Genome Editing ◽

Drug Targets ◽

Targeted Mutagenesis ◽

Dna Repair Mechanisms ◽

Repair Mechanisms

Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) genome editing has become a standard method in molecular biology, for the establishment of genetically modified cellular and animal models, for the identification and validation of drug targets in animals, and is heavily tested for use in gene therapy of humans. While the efficiency of CRISPR mediated gene targeting is much higher than of classical targeted mutagenesis, the efficiency of CRISPR genome editing to introduce defined changes into the genome is still low. Overcoming this problem will have a great impact on the use of CRISPR genome editing in academic and industrial research and the clinic. This review will present efforts to achieve this goal by small molecules, which modify the DNA repair mechanisms to facilitate the precise alteration of the genome.

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Toward Precision Genome Editing in Crop Plants

Molecular Plant ◽

10.1016/j.molp.2020.04.008 ◽

2020 ◽

Vol 13 (6) ◽

pp. 811-813 ◽

Cited By ~ 4

Author(s):

Jingying Li ◽

Huiyuan Li ◽

Jilin Chen ◽

Lei Yan ◽

Lanqin Xia

Keyword(s):

Genome Editing ◽

Crop Plants

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Creating valuable crop plants utilized by molecular breeding and genome editing techniques

JSM Mycotoxins ◽

10.2520/myco.68-2-5 ◽

2018 ◽

Vol 68 (2) ◽

pp. 99-104

Author(s):

Hiroaki Shimada

Keyword(s):

Genome Editing ◽

Molecular Breeding ◽

Crop Plants

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CRISPR/Cas9-Mediated Targeted Mutagenesis of Wild Soybean (Glycine soja) Hairy Roots Altered the Transcription Profile of the Mutant

Journal of Agricultural Science ◽

10.5539/jas.v12n9p14 ◽

2020 ◽

Vol 12 (9) ◽

pp. 14

Author(s):

Fengjuan Niu ◽

Qiyan Jiang ◽

Rui Cheng ◽

Xianjun Sun ◽

Zheng Hu ◽

...

Keyword(s):

Glycine Max ◽

Genome Editing ◽

Hairy Roots ◽

Glycine Soja ◽

Differentially Expressed Gene ◽

Wild Soybean ◽

Targeted Mutagenesis ◽

Functional Identification ◽

Transcription Profiles ◽

Biallelic Mutations

Clustered Regularly Interspaced Short Palindromic Repeat/CRISPR-associated protein 9 (CRISPR/Cas9) system has been regularly applied for genome editing and gene function identification in wild soybean (Glycine max) cultivars. However, till date no studies have demonstrated successful mutagenesis in wild soybean (Glycine soja) which is the ancestor of Glycine max and rich in stress tolerance genes. In the current study, we report the successful creation of mutations in the loci encoding plasma membrane Na+/H+ antiporter (SOS1) and nonselective cation channels (NSCC) in wild soybean hairy roots using the CRISPR/Cas9 system. Two genes, GsSOS1 and GsNSCC, were mutagenized with frequencies of 28.5% and 39.9%, respectively. Biallelic mutations in GsSOS1 were detected in transgenic hairy roots. GsSOS1 mutants exhibited altered Na+/K+ ratios in the roots under both control and salt-treated conditions. However, no significant effects of GsNSCC mutation on Na+/K+ ratios were observed. RNA-Seq analysis revealed that both GsSOS1 and GsNSCC mutation altered the transcription profiles in mutant roots. Many differentially expressed gene sets that are associated with various cellular functions were identified. Our results demonstrated that CRISPR/Cas9 systems as powerful tools for wild soybean genome editing and would significantly advance the gene mining and functional identification in wild soybean.

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