Present and future prospects for wheat improvement through genome editing and advanced technologies - PubMed (original) (raw)

Review

Present and future prospects for wheat improvement through genome editing and advanced technologies

Shaoya Li et al. Plant Commun. 2021.

Abstract

Wheat (Triticum aestivum, 2_n_ = 6_x_ = 42, AABBDD) is one of the most important staple food crops in the world. Despite the fact that wheat production has significantly increased over the past decades, future wheat production will face unprecedented challenges from global climate change, increasing world population, and water shortages in arid and semi-arid lands. Furthermore, excessive applications of diverse fertilizers and pesticides are exacerbating environmental pollution and ecological deterioration. To ensure global food and ecosystem security, it is essential to enhance the resilience of wheat production while minimizing environmental pollution through the use of cutting-edge technologies. However, the hexaploid genome and gene redundancy complicate advances in genetic research and precision gene modifications for wheat improvement, thus impeding the breeding of elite wheat cultivars. In this review, we first introduce state-of-the-art genome-editing technologies in crop plants, especially wheat, for both functional genomics and genetic improvement. We then outline applications of other technologies, such as GWAS, high-throughput genotyping and phenotyping, speed breeding, and synthetic biology, in wheat. Finally, we discuss existing challenges in wheat genome editing and future prospects for precision gene modifications using advanced genome-editing technologies. We conclude that the combination of genome editing and other molecular breeding strategies will greatly facilitate genetic improvement of wheat for sustainable global production.

Keywords: CRISPR/Cas; GWAS; genome editing; speed breeding; wheat (Triticum aestivum L.).

© 2021 The Authors.

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Figures

Figure 1

Figure 1

A diagram showing major CRISPR/Cas toolboxes. (A) CRISPR/Cas-mediated mutation can generate loss-of-function alleles by introducing DSBs in the coding region of targeted genes by the error-prone non-homologous end joining (NHEJ) pathway. Gene insertion and replacement can be obtained by DSB-mediated homology-directed repair (HDR). (B) CRISPR/Cas9-mediated cytosine base editing system. An sgRNA and a catalytically impaired Cas9 complex bind to the target sequence in genomic DNA. The cytidine deaminase catalyzes the deamination of cytosine (C) in a narrow window of the non-targeted strand and makes the base change from C to U (uracil) at a target site. U is recognized as thymine (T) during DNA replication, ultimately resulting in a C∗G-to-T∗A conversion. (C) CRISPR/Cas9-mediated adenine base editing system. An adenosine deaminase and Cas9 nickase (nCas9 (D10A)) fusion binds to the target site in a gRNA-programmed manner. The adenosine deaminase catalyzes an A (adenine) to I (inosine) change at the target site. During replication, the original A is replaced with G (guanine). Finally, A∗T-to-G∗C conversion is achieved in the DNA strand. (D) CRISPR/Cas9-mediated prime editing system. A prime editing guide RNA (pegRNA) in a complex with a Cas9 nickase (nCas9 (H840A)) binds to the target sequence in the genomic DNA. M-MLV-RT (Moloney murine leukemia virus reverse transcriptase) helps the 3′ DNA end from the prime-binding site to prime the reverse transcription of an edit-encoding extension from the pegRNA directly into the target site. PBS, primer-binding site; RT, reverse transcript.

Figure 2

Figure 2

Breeding of a green super wheat variety through CRISPR/Cas-mediated gene editing and other breeding technologies. (A) Genome sequencing. Wheat genome and pan-genome sequencing provide basic information for designing an sgRNA target and the evaluation of off-target effects in wheat genome editing. (B) GWAS analysis. GWAS enables the association of specific genes, SNPs, or markers on a chromosome with a specific trait. (C) A CRISPR/Cas-mediated multiplex system for multiple gene knockouts (KOs). (D) CRISPR/Cas-mediated HDR remains to be investigated as a means to improve HDR efficiency in wheat. (E) Development of a module for simultaneous HDR and/or base editing (BE) and knockout would greatly facilitate the translational breeding process for pyramiding favorable alleles in an elite wheat variety in a shorter time. (F) Development of diverse genotype-independent strategies. Genotype-independent strategies enable transformation of recalcitrant wheat varieties, thus facilitating the use of genome editing in diverse elite wheat germplasm. (G) Gene stacking by synthetic biology. Synthetic biology enables the accumulation of multiple transgenes of interest in the same plant genome to stack beneficial traits or generate a novel trait. (H) Speed breeding. Speed breeding enables a shortened generation time for seed harvesting in wheat. KO, knockout; BE, base editing; HDR, homology-directed repair.

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References

    1. Aird E.J., Lovendahl K.N., Martin A., Harris R.S., Gordon W.R. Increasing Cas9-mediated homology-directed repair efficiency through covalent tethering of DNA repair template. Commun. Biol. 2018;1:54. - PMC - PubMed
    1. Altpeter F., Springer N.M., Bartley L.E., Blechl A.E., Brutnell T.P., Citovsky V., Conrad L.J., Gelvin S.B., Jackson D.P., Kausch A.P. Advancing crop transformation in the era of genome editing. Plant Cell. 2016;28:1510–1520. - PMC - PubMed
    1. Anzalone A.V., Randolph P.B., Davis J.R., Sousa A.A., Koblan L.W., Levy J.M., Chen P.J., Wilson C., Newby G.A., Raguram A. Search-and-replace genome editing without double-strand breaks or donor DNA. Nature. 2019;576:149–157. - PMC - PubMed
    1. Araus J.L., Kefauver S.C., Zaman-Allah M., Olsen M.S., Cairns J.E. Translating high-throughput phenotyping into genetic gain. Trends Plant Sci. 2018;23:451–466. - PMC - PubMed
    1. Ashikari M., Matsuoka M. Identification, isolation and pyramiding of quantitative trait loci for rice breeding. Trends Plant Sci. 2006;11:344–350. - PubMed

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