Base Editing: The Ever Expanding Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) Tool Kit for Precise Genome Editing in Plants

Abstract

Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR associated protein 9 (Cas9), a newly developed genome-editing tool, has revolutionized animal and plant genetics by facilitating modification of target genes. This simple, convenient base-editing technology was developed to improve the precision of genome editing. Base editors generate precise point mutations by permanent base conversion at a specific point, with very low levels of insertions and deletions. Different plant base editors have been established by fusing various nucleobase deaminases with Cas9, Cas13, or Cas12a (Cpf1), proteins. Adenine base editors can efficiently convert adenine (A) to guanine (G), whereas cytosine base editors can convert cytosine (C) to thymine (T) in the target region. RNA base editors can induce a base substitution of A to inosine (I) or C to uracil (U). In this review, we describe the precision of base editing systems and their revolutionary applications in plant science; we also discuss the limitations and future perspectives of this approach.

Harnessing the potential of plant transcription factors in developing climate resilient crops to improve global food security: Current and future perspectives

“…As a result, a double stranded break occurs at the target site, the repair of which causes mutations in the form of insertions or deletions or in some cases frameshifts. These mutants can clarify the role of the TF under consideration ( Ahmad et al, 2020 ; Monsur et al, 2020 ).…”

Genome editing for crop improvement: A perspective from India

“…Initially, BE1 was invented with fusing cytidine deaminase, BE2 was an improvement over BE1 in that it incorporates uracil DNA glycosylase inhibitor (UGI), BE3 is dCas9 replaced by nCas9 (nickase) while BE4 has rat/lamprey/human APOBEC1 with nickase (for detailed review, Bharat et al 2019). NHEJ is preferred approach where loss of function of a gene is desired (Monsur et al 2020). Nowadays, both adenine and cytidine base editors are available which facilitates base conversion (by deamination) in a narrow window (see Nishida et al 2016).…”

Metabolic Engineering Strategies of Industrial Hemp (Cannabis sativa L.): A Brief Review of the Advances and Challenges

“…Base editors such as cytosine base editor and adenine base editor are basically composed of cytosine or adenosine deaminase domain, respectively, and catalytically inactive CRISPR-Cas9 domain (Kang et al, 2018). The base-editing system can generate a single-base change or single nucleotide polymorphisms (SNP), thereby facilitating Braemer and Paris, 1987Leaf Carmagnola, Fibranova, Uniko, and Kompolti Mandolino and Ranalli, 1999Seedlings Fedora 19 and Felina 34 Mackinnon et al, 2000Stem and leaves Anka, Uniko-B, Felina-34, and Kompolti Feeney and Punja, 2003Internodes, axillary buds, and petioles Silesia, Fibrimon-24, Novosadska, Juso-15, and Fedrina-74 Slusarkiewicz-Jarzina et al, 2005 Roots, leaves, and stem Beniko, Bialobrzeskie, and Silesia Plawuszewski et al, 2006 Leaves, flowers, and 4 plant breeding and basic research (Monsur et al, 2020). In Cannabis, more than 14,000 SNPs were genotyped in both drug type and fiber type strains (Sawler et al, 2015).…”

“…Base editors such as cytosine base editor and adenine base editor are basically composed of cytosine or adenosine deaminase domain, respectively, and catalytically inactive CRISPR–Cas9 domain ( Kang et al, 2018 ). The base-editing system can generate a single-base change or single nucleotide polymorphisms (SNP), thereby facilitating plant breeding and basic research ( Monsur et al, 2020 ). In Cannabis , more than 14,000 SNPs were genotyped in both drug type and fiber type strains ( Sawler et al, 2015 ).…”