Researchers working to advance genome engineering in crops face many challenges, including simultaneously introducing diverse genome edits. Although a major goal of modern crop breeding is to efficiently combine multiple desirable traits by “stacking” the favorable alleles that contribute to those traits in a single crop variety, current strategies are time-consuming and inefficient. Now, a team led by Caixia Gao, PhD, professor at the Institute of Genetics and Developmental Biology of the Chinese Academy of Sciences, has developed a genome engineering platform that allows multiple trait stacking in crops by combining gene knockout, precise sequence editing, and chromosome engineering within a single framework. The advance is “a twin prime editing-based knockout (TKO) system that installs stop codon clusters (SCCs) for precise translational termination with minimal in-frame mutations.” TKO achieved knockout efficiencies of up to 70.5%, 58.6% and 75.1% in rice, maize, and wheat protoplasts, respectively. This work was published in Nature Biotechnology in the article, “Multiplexed, precise genome engineering in monocots with twin prime editing systems.” The researchers first developed a precise and efficient gene knockout tool called twin prime editing (twinPE)-mediated gene knockout (TKO), which precisely inserts a small fragment containing a stop codon cluster at the target site. TKO achieves predictable gene disruption through precise installation of stop codons, avoiding in-frame indels caused by insertions or deletions in multiples of three nucleotides, which are often seen in Cas9 systems. In protoplasts, TKO demonstrated efficient knockout capabilities in monocot crops such as rice, wheat, and maize. In regenerated T0…
