Mutagenesis and genome editing in crop improvement: perspectives for the global regulatory landscape

• Published in: Trends in plant science Vol. 26; no. 12; pp. 1258 - 1269
• Main Authors: Jung, Christian, Till, Bradley
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.12.2021; Elsevier BV
• Subjects: allelic variation; CRISPR; CRISPR-Cas Systems - genetics; Crop improvement; Crops, Agricultural - genetics; Editing; Gene Editing; Genetic diversity; Genome editing; Genome, Plant - genetics; Genomes; genomics; molecular marker; Mutagenesis; Mutagenesis - genetics; Mutants; Mutation; Offspring; Plant Breeding; Plants, Genetically Modified; Polyploidy; progeny; Random mutagenesis; selection; Site-directed mutagenesis; mutation; genome editing; plant breeding; selection; molecular marker
• ISSN: 1360-1385; 1878-4372; 1878-4372
• DOI: 10.1016/j.tplants.2021.08.002

Plant breeding depends on broad genetic variation. New allelic variation can be produced by targeted or random mutagenesis. Seemingly, random mutagenesis is outdated because clustered regularly interspaced short palindromic repeats (CRISPR)–Cas technology is much more precise and potentially faster. Unfortunately, genome editing is not accessible to breeders in many countries due to legal constraints. Therefore, random mutagenesis remains a vital method to create new allelic variation. Mutant offspring, however, suffer from a heavy mutation load, and application in polyploid crops is limited because multiple mutations are typically required. Exploiting random mutations became more efficient due to recent technological advancements, such as sequence-based mutant screening and genomic background selection. In this review, random and targeted mutagenesis will be compared, highlighting the legal situation. Mutagenesis is an important tool to increase genetic variation in plant breeding.Targeted mutagenesis offers three advantages: targeting one gene (family) only, inducing multiple mutations simultaneously, and avoiding background mutations.Random mutagenesis is the only technology available to breeders in the EC and other countries due to legal constraints.Random mutagenesis is becoming more attractive when whole-genome sequences of large mutant populations are available.Random mutagenesis suffers from a high mutation load. New strategies have been developed to reduce the mutation load in a shorter time.A combination of targeted and random mutagenesis can be used to validate gene function and phenotype while producing an improved crop not subject to legal restrictions.