Synergistic Use of Site-Specific Recombination and CRISPR-Cas Platforms for Complex Plant Genome Engineering

Site-specific recombination (SSR) systems and CRISPR-Cas platforms represent two major classes of genome-engineering technologies that have been widely applied across diverse organisms, including plants. SSR systems, including bidirectional SSR and unidirectional SSR systems, provide highly predictable DNA excision, integration, and inversion, whereas CRISPR-Cas systems enable programmable, RNA-guided genome editing with unprecedented flexibility and efficiency. This review outlines the fundamental molecular mechanisms underlying both SSR-mediated recombination and CRISPR-Cas-based genome editing in plants, emphasizing how each system achieves targeted genomic modification. We compare their respective strengths, limitations, and optimal use cases in plant biotechnology. Recent advances have demonstrated that combining SSR and CRISPR-Cas technologies in hybrid strategies can overcome the constraints of either system alone, enabling more precise, modular, and complex genome engineering. We highlight emerging applications of these integrated approaches and discuss current literature illustrating their potential to advance next-generation plant breeding and synthetic biology.