From Gene Knockouts to Genome Remodeling: Large DNA Fragment Deletion Technologies in Plants.

Large DNA fragment deletion (LDFD) provides a powerful means to reconfigure plant genomes at the kilobase to megabase scale, enabling the dissection of genome function, elucidation of non-coding regulatory elements, modulation of gene dosage, reorganization of chromosomal architecture, and implementation of synthetic biology designs. In this review, we systematically compare the mechanisms, efficiencies, advantages, and limitations of the major LDFD technologies that have been applied in plants, including ZFNs, TALENs, CRISPR/Cas systems (Cas9, Cas12a, Cas3), site-specific recombinases, transposon-based systems, and prime editing-derived strategies. We highlight how plant-specific features of chromatin organization and DNA repair constrain large deletions, and discuss the current bottlenecks in achieving efficient, precise, and predictable LDFD across diverse crop genomes. Finally, we outline future directions for plant LDFD, emphasizing AI-assisted design of nucleases and recombinases, protein-directed evolution, and improved DNA- and RNP-based delivery systems. Together, these advances are expected to transform LDFD from a specialized tool into a broadly accessible platform for functional genomics, trait engineering and rational genome design in plants.