Multiplex genome editing |
- Rapid stacking of multiple traits - Improvement of complex traits in few generations - Efficient strategy for gene discovery |
- Larger vectors may lower transformation efficiency - Different sgRNA efficiencies may result in unequal mutation rates - Likely increase in off-target mutation rates |
Zhang et al., 2020Zhang J, Zhang X, Chen R, Yang L, Fan K, Liu Y, Wang G, Ren Z and Liu Y (2020) Generation of transgene-free semidwarf maize plants by gene editing of GIBBERELLIN-OXIDASE20-3 using CRISPR/Cas9. Front Plant Sci 11:1048.; Liu et al., 2021Liu L, Gallagher J, Arevalo ED, Chen R, Skopelitis T, Wu Q, Bartlett M and Jackson D (2021) Enhancing grain-yield-related traits by CRISPR-Cas9 promoter editing of maize CLE genes. Nat Plants 7:287-294.; Gong et al., 2021Gong C, Huang S, Song R and Qi W (2021) Comparative study between the CRISPR/Cpf1 (Cas12a) and CRISPR/Cas9 systems for multiplex gene editing in maize. Agriculture 11:429.; Liu et al., 2022Liu X, Zhang S, Jiang Y, Yan T, Fang C, Hou Q, Wu S, Xie K, An X and Wan X (2022) Use of CRISPR/Cas9-based gene editing to simultaneously mutate multiple homologous genes required for pollen development and male fertility in maize. Cells 11:439.; Lorenzo et al., 2022Lorenzo CD, Debray K, Herwegh D, Develtere W, Impens L, Schaumont D, Vandeputte W, Aesaert S, Coussens G, Boe Y de et al. (2022) BREEDIT: A novel multiplex genome editing strategy to improve complex quantitative traits in maize. Plant Cell 35:218-238.
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Base editing |
- Precise and specific point mutations - Good option for editing regulatory sequences |
- Less applicable to generate gene knockouts |
Li et al., 2020Li Y, Zhu J, Wu H, Liu C, Huang C, Lan J, Zhao Y and Xie C (2020) Precise base editing of non-allelic acetolactate synthase genes confers sulfonylurea herbicide resistance in maize. Crop J 8:449-456.
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Prime editing |
- Precise point and small mutations - Good option for editing regulatory sequences |
- Still very low efficiency in plants - Guide design (pegRNA) more complex than standard sgRNA - Optimization of many variables are still required |
Jiang et al., 2020Jiang Y-Y, Chai Y-P, Lu M-H, Han X-L, Lin Q, Zhang Y, Zhang Q, Zhou Y, Wang X-C, Gao C et al. (2020) Prime editing efficiently generates W542L and S621I double mutations in two ALS genes in maize. Genome Biol 21:257.
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Promoter editing |
- Allows strategies for increasing or altering expression patterns - Avoids modifications in protein-coding sequences |
- Complexity of regulatory sequences may result in poor predictability of outcomes |
Shi et al., 2017Shi J, Gao H, Wang H, Lafitte HR, Archibald RL, Yang M, Hakimi SM, Mo H and Habben JE (2017) ARGOS8 variants generated by CRISPR-Cas9 improve maize grain yield under field drought stress conditions. Plant Biotechnol J 15:207-216.; Liu et al., 2021Liu L, Gallagher J, Arevalo ED, Chen R, Skopelitis T, Wu Q, Bartlett M and Jackson D (2021) Enhancing grain-yield-related traits by CRISPR-Cas9 promoter editing of maize CLE genes. Nat Plants 7:287-294.
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In-trans genome editing |
- Circumvents transformation recalcitrance - May generate monoallelic mutations when combined with haploid inducer strategy (HI-Edit / IMGE) |
- Lower editing efficiency when compared to approaches based on stable transformation |
Li et al., 2017Li C, Liu C, Qi X, Wu Y, Fei X, Mao L, Cheng B, Li X and Xie C (2017) RNA-guided Cas9 as an in vivo desired-target mutator in maize. Plant Biotechnol J 15:1566-1576.; Kelliher et al., 2019Kelliher T, Starr D, Su X, Tang G, Chen Z, Carter J, Wittich PE, Dong S, Green J, Burch E et al. (2019) One-step genome editing of elite crop germplasm during haploid induction. Nat Biotechnol 37:287-292.; Wang B et al., 2019Wang C, Liu Q, Shen Y, Hua Y, Wang J, Lin J, Wu M, Sun T, Cheng Z, Mercier R et al. (2019) Clonal seeds from hybrid rice by simultaneous genome engineering of meiosis and fertilization genes. Nat Biotechnol 37:283-286.; Qi et al., 2020Qi X, Wu H, Jiang H, Zhu J, Huang C, Zhang X, Liu C and Cheng B (2020) Conversion of a normal maize hybrid into a waxy version using in vivo CRISPR/Cas9 targeted mutation activity. Crop J 8:440-448.
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