Gene Editing in Forest Tree Breeding for Stress Resistance: From Mechanisms to Future Prospects

Forest ecosystems face escalating threats from climate change alongside a surging demand for sustainable bioproducts. While conventional tree breeding is inherently constrained by long generation cycles, high heterozygosity, and complex genomes, CRISPR-based genome editing provides a precision framework for targeted genetic improvement. This review synthesises the fundamental principles and limitations of multiple gene-editing technologies, with a particular emphasis on CRISPR systems (Cas9, Cas12, and Cas13), in the specific context of woody perennial biology. Recent applications in key forest genera, including Populus, Pinus, and Eucalyptus, demonstrate the efficacy of these gene-editing tools in manipulating complex traits, such as rewiring phytohormone signalling networks for drought tolerance or remodelling root system architecture to combat abiotic stress. We critically evaluate persistent translational bottlenecks in forest tree genome editing, with a specific focus on recalcitrant, genotype-dependent regeneration and the multifaceted challenges of long-term field validation. Finally, we highlight how synergising CRISPR technologies with multi-omics, genomic selection, and high-throughput phenomics can accelerate the development and application of climate-resilient woody perennials.