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Yamada H, Kato N, Ichikawa M, Mannen K, Kiba T, Osakabe Y, Sakakibara H, Matsui M, Okamoto T. DNA- and Selectable-Marker-Free Genome-Editing System Using Zygotes from Recalcitrant Maize Inbred B73. PLANT & CELL PHYSIOLOGY 2024; 65:729-736. [PMID: 38288629 DOI: 10.1093/pcp/pcae010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 01/17/2024] [Accepted: 01/22/2024] [Indexed: 05/31/2024]
Abstract
Genome-editing tools such as the clustered regularly interspaced short palindromic repeats/Cas9 (CRISPR/Cas9) system have become essential tools for increasing the efficiency and accuracy of plant breeding. Using such genome-editing tools on maize, one of the most important cereal crops of the world, will greatly benefit the agriculture and the mankind. Conventional genome-editing methods typically used for maize involve insertion of a Cas9-guide RNA expression cassette and a selectable marker in the genome DNA; however, using such methods, it is essential to eliminate the inserted DNA cassettes to avoid legislative concerns on gene-modified organisms. Another major hurdle for establishing an efficient and broadly applicable DNA-free genome-editing system for maize is presented by recalcitrant genotypes/cultivars, since cell/tissue culture and its subsequent regeneration into plantlets are crucial for producing transgenic and/or genome-edited maize. In this study, to establish a DNA-free genome-editing system for recalcitrant maize genotypes/cultivars, Cas9-gRNA ribonucleoproteins were directly delivered into zygotes isolated from the pollinated flowers of the maize-B73 cultivar. The zygotes successfully developed and were regenerated into genome-edited plantlets by co-culture with phytosulfokine, a peptide phytohormone. The method developed herein made it possible to obtain DNA- and selectable-marker-free genome-edited recalcitrant maize genotypes/cultivars with high efficiency. This method can advance the molecular breeding of maize and other important cereals, regardless of their recalcitrant characteristics.
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Affiliation(s)
- Hajime Yamada
- Agri-Bio Research Center, KANEKA CORPORATION, Higashibara 700, Iwata, Shizuoka, 438-0802 Japan
- Plant Innovation Center, Japan Tobacco, Inc., Higashibara 700, Iwata, Shizuoka, 438-0802 Japan
| | - Norio Kato
- Plant Innovation Center, Japan Tobacco, Inc., Higashibara 700, Iwata, Shizuoka, 438-0802 Japan
- Plant Breeding Innovation Laboratory, RIKEN Cluster for Science, Technology and Innovation Hub, Tsurumi, Yokohama, 230-0045 Japan
- Department of Biological Sciences, Tokyo Metropolitan University, Minami-osawa 1-1, Hachioji, Tokyo, 192-0392 Japan
| | - Masako Ichikawa
- Agri-Bio Research Center, KANEKA CORPORATION, Higashibara 700, Iwata, Shizuoka, 438-0802 Japan
- Plant Innovation Center, Japan Tobacco, Inc., Higashibara 700, Iwata, Shizuoka, 438-0802 Japan
| | - Keiko Mannen
- Plant Breeding Innovation Laboratory, RIKEN Cluster for Science, Technology and Innovation Hub, Tsurumi, Yokohama, 230-0045 Japan
| | - Takatoshi Kiba
- Plant Breeding Innovation Laboratory, RIKEN Cluster for Science, Technology and Innovation Hub, Tsurumi, Yokohama, 230-0045 Japan
- Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601 Japan
| | - Yuriko Osakabe
- Plant Breeding Innovation Laboratory, RIKEN Cluster for Science, Technology and Innovation Hub, Tsurumi, Yokohama, 230-0045 Japan
- Department of Life Science and Technology, Tokyo Institute of Technology, Yokohama, 226-8501 Japan
| | - Hitoshi Sakakibara
- Plant Breeding Innovation Laboratory, RIKEN Cluster for Science, Technology and Innovation Hub, Tsurumi, Yokohama, 230-0045 Japan
- Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601 Japan
| | - Minami Matsui
- Plant Breeding Innovation Laboratory, RIKEN Cluster for Science, Technology and Innovation Hub, Tsurumi, Yokohama, 230-0045 Japan
- RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045 Japan
| | - Takashi Okamoto
- Plant Breeding Innovation Laboratory, RIKEN Cluster for Science, Technology and Innovation Hub, Tsurumi, Yokohama, 230-0045 Japan
- Department of Biological Sciences, Tokyo Metropolitan University, Minami-osawa 1-1, Hachioji, Tokyo, 192-0392 Japan
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Koller F, Cieslak M. A perspective from the EU: unintended genetic changes in plants caused by NGT-their relevance for a comprehensive molecular characterisation and risk assessment. Front Bioeng Biotechnol 2023; 11:1276226. [PMID: 37965049 PMCID: PMC10641861 DOI: 10.3389/fbioe.2023.1276226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Accepted: 10/16/2023] [Indexed: 11/16/2023] Open
Abstract
Several regions in the world are currently holding discussions in regard to the regulation of new genomic techniques (NGTs) and their application in agriculture. The European Commission, for instance, is proposing the introduction of specific regulation for NGT plants. Various questions need to be answered including e.g., the extent to which NGT-induced intended and unintended genetic modifications must be subjected to a mandatory risk assessment as part of an approval procedure. This review mostly focuses on findings in regard to unintended genetic changes that can be caused by the application of NGTs. More specifically, the review deals with the application of the nuclease CRISPR/Cas, which is currently the most important tool for developing NGT plants, and its potential to introduce double strand breaks (DSBs) at a targeted DNA sequence. For this purpose, we identified the differences in comparison to non-targeted mutagenesis methods used in conventional breeding. The review concludes that unintended genetic changes caused by NGT processes are relevant to risk assessment. Due to the technical characteristics of NGTs, the sites of the unintended changes, their genomic context and their frequency (in regard to specific sites) mean that the resulting gene combinations (intended or unintended) may be unlikely to occur with conventional methods. This, in turn, implies that the biological effects (phenotypes) can also be different and may cause risks to health and the environment. Therefore, we conclude that the assessment of intended as well as unintended genetic changes should be part of a mandatory comprehensive molecular characterisation and risk assessment of NGT plants that are meant for environmental releases or for market authorisation.
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Affiliation(s)
- Franziska Koller
- Fachstelle Gentechnik und Umwelt (FGU), Munich, Bavaria, Germany
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Nishihara M, Muranaka T. Preface to the special issue "Current Status and Future Prospects for the Development of Crop Varieties and Breeding Materials Using Genome Editing Technology". PLANT BIOTECHNOLOGY (TOKYO, JAPAN) 2023; 40:181-184. [PMID: 38293252 PMCID: PMC10824492 DOI: 10.5511/plantbiotechnology.23.0000p] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Affiliation(s)
| | - Toshiya Muranaka
- Department of Biotechnology, Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871, Japan
- Institution for Open and Transdisciplinary Research Initiatives, Osaka University, Suita, Osaka 565-0871, Japan
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Umemoto N, Yasumoto S, Yamazaki M, Asano K, Akai K, Lee HJ, Akiyama R, Mizutani M, Nagira Y, Saito K, Muranaka T. Integrated gene-free potato genome editing using transient transcription activator-like effector nucleases and regeneration-promoting gene expression by Agrobacterium infection. PLANT BIOTECHNOLOGY (TOKYO, JAPAN) 2023; 40:211-218. [PMID: 38420569 PMCID: PMC10901161 DOI: 10.5511/plantbiotechnology.23.0530a] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 05/30/2023] [Indexed: 03/02/2024]
Abstract
Genome editing is highly useful for crop improvement. The method of expressing genome-editing enzymes using a transient expression system in Agrobacterium, called agrobacterial mutagenesis, is a shortcut used in genome-editing technology to improve elite varieties of vegetatively propagated crops, including potato. However, with this method, edited individuals cannot be selected. The transient expression of regeneration-promoting genes can result in shoot regeneration from plantlets, while the constitutive expression of most regeneration-promoting genes does not result in normally regenerated shoots. Here, we report that we could obtain genome-edited potatoes by positive selection. These regenerated shoots were obtained via a method that combined a regeneration-promoting gene with the transient expression of a genome-editing enzyme gene. Moreover, we confirmed that the genome-edited potatoes obtained using this method did not contain the sequence of the binary vector used in Agrobacterium. Our data have been submitted to the Japanese regulatory authority, the Ministry of Education, Culture, Sports, Science and Technology (MEXT), and we are in the process of conducting field tests for further research on these potatoes. Our work presents a powerful method for regarding regeneration and acquisition of genome-edited crops through transient expression of regeneration-promoting gene.
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Affiliation(s)
- Naoyuki Umemoto
- RIKEN Center for Sustainable Resource Science, Kanagawa 230-0045, Japan
| | - Shuhei Yasumoto
- Graduate School of Engineering, Osaka University, Osaka 565-0871, Japan
| | - Muneo Yamazaki
- National Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, Ibaraki 305-8518, Japan
| | - Kenji Asano
- National Agricultural Research Center for Hokkaido Region, National Agriculture and Food Research Organization, Hokkaido 082-0081, Japan
| | - Kotaro Akai
- National Agricultural Research Center for Hokkaido Region, National Agriculture and Food Research Organization, Hokkaido 082-0081, Japan
| | - Hyoung Jae Lee
- Graduate School of Agricultural Science, Kobe University, Hyogo 657-8501, Japan
| | - Ryota Akiyama
- Graduate School of Agricultural Science, Kobe University, Hyogo 657-8501, Japan
| | - Masaharu Mizutani
- Graduate School of Agricultural Science, Kobe University, Hyogo 657-8501, Japan
| | - Yozo Nagira
- Agri-Bio Research Center, Kaneka Co., Shizuoka 438-0802, Japan
| | - Kazuki Saito
- RIKEN Center for Sustainable Resource Science, Kanagawa 230-0045, Japan
| | - Toshiya Muranaka
- Graduate School of Engineering, Osaka University, Osaka 565-0871, Japan
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