New Hope for Genome Editing in Cultivated Grasses: CRISPR Variants and Application

Abstract

With the advent of Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and CRISPR-associated protein (Cas) mediated genome editing, crop improvement has progressed significantly in recent years. In this genome editing tool, CRISPR-associated Cas nucleases are restricted to their target of DNA by their preferred protospacer adjacent motifs (PAMs). A number of CRISPR-Cas variants have been developed e.g. CRISPR-Cas9, -Cas12a and -Cas12b, with different PAM requirements. In this mini-review, we briefly explain the components of the CRISPR-based genome editing tool for crop improvement. Moreover, we intend to highlight the information on the latest development and breakthrough in CRISPR technology, with a focus on a comparison of major variants (CRISPR-Cas9, -Cas12a, and -Cas12b) to the newly developed CRISPR-SpRY that have nearly PAM-less genome editing ability. Additionally, we briefly explain the application of CRISPR technology in the improvement of cultivated grasses with regard to biotic and abiotic stress tolerance as well as improving the quality and yield.

Next-generation CRISPR gene-drive systems using Cas12a nuclease

“…A double drive system, in which Cas9 and Cas12a would target sex-determination genes at two locations (within the same gene or at distinct loci), could improve gene drive spread, as indels generated at one target site would not affect the propagation of the other gene drive cassette, and ultimately ensure its full propagation while improving current suppression strategies. It is important to note that Cas9 and Cas12a have different PAM requirements and should not interfere with each other; Cas9 needs a NGG PAM site and Cas12a requires a TTTN sequence for targeting 41 . Therefore, the use of Cas12a for vector control will also facilitate targeting genomic regions that we could not attack before due to restrictions with the Cas9 PAM site.…”

Phenotypic and genetic characterization of an Avena sativa L. germplasm collection of diverse origin: implications for food-oat breeding in Chile

“…Transformation of oats using biolistic bombardment improved the tolerance to osmotic stress in transgenic plants ( Maqbool et al., 2009 ). Gene-editing has been successfully applied in the breeding of wheat, rice, and barley to improve tolerance to biotic and abiotic stresses, grain quality and yield ( Riaz et al., 2022 ). However, despite the usefulness of these modern techniques in genetic breeding, they are not currently accepted for food production by regulatory agencies in Chile.…”

Leveraging the sugarcane CRISPR/Cas9 technique for genetic improvement of non-cultivated grasses

“…Originally, CRISPR/Cas9 was discovered in bacteria and archaea immune systems having a role in detecting and subsequently degrading the invasive DNA from bacteriophages and plasmids (Peng et al, 2015;Ma et al, 2016). Recently, CRISPR has been developed as a revolutionary gene editing technique that performs precise modification of DNA within the host's genome (Hussin et al, 2022;Riaz et al, 2022;Krishna et al, 2023). The Cas9 part refers to the CRISPR associated protein 9, which serves as molecular scissors.…”