Transposon-derived genome editors in plants: from compact nucleases to large-fragment integration and regeneration...

CRISPR/Cas technology has been transformative for genome editing, enabling the precise integration of large DNA fragments-a capability essential for advanced genome (re)writing in plants, such as for trait stacking and pathway engineering. However, several new RNA-guided systems derived from transposable elements (TEs) have shown promise for plant genome editing, thereby enriching the toolkit available for plant engineering. This review comprehensively analyzes these emerging TE-based editors, including OMEGA nucleases (TnpB, IscB, Fanzor), CRISPR-associated transposases (CASTs), and R2 retrotransposon-derived systems. We detail their distinct architectures, evolutionary origins, and unique advantages over traditional Cas9, such as their compact size, simplified guide RNAs, and staggered DNA cleavage. We critically evaluate their nascent applications in plant models, highlighting ongoing challenges in editing efficiency, delivery, and specificity. Notably, CASTs and R2 retrotransposon-derived systems show particular promise for programmable large-fragment DNA integration, offering potential solutions for next-generation plant genome writing applications. We also examine the critical link between genome editing and plant regeneration, discussing phytohormonal and morphogenic regulators (e.g., BBM, WUS), and innovative tissue-culture-free methods, such as Cut-Dip-Budding. By comparing their merits and limitations, we position these systems not as replacements but as complementary tools within an expanding genome-editing toolkit. Integrating optimized TE-based editors with robust regeneration strategies is poised to unlock new frontiers in plant synthetic biology and crop improvement.