Application of CRISPR/Cas genome editing in woody plant trait improvement

CRISPR (clustered regularly interspaced short palindromic repeats) is a system found in bacteria and archaea that functions as an immune defense mechanism against foreign DNA or RNA. Due to its ability to edit specific target genes within the genome using RNA-guided Cas nucleases, CRISPR has become a valuable tool in genome research and genome modification. Forests play a crucial role in various ecological functions, including soil and water conservation, regulation of climate, prevention of wind and sand erosion, and pollution removal. Additionally, they provide abundant raw materials for human production activities, making them vital for promoting sustainable development in agriculture and forestry economies. However, woody plants face challenges such as inbreeding depression due to their long reproductive periods and generation cycles spanning several decades. With the rapid development of molecular breeding technology, the application of genome editing-driven molecular design breeding offers a promising approach to improve the genetics of woody plants. The CRISPR genome editing system provides opportunities to expedite the improvement of woody plant traits. By manipulating the genes related to growth and disease resistance, it is possible to cultivate woody plant varieties that can better adapt to diverse environmental conditions. This, in turn, enhances growth rates, stress resistance, and quality characteristics of woody plants. This review introduces several CRISPR/Cas system genome editing technologies applicable to woody plants, including Cas9, Cas12a, Cas13, Cas14a, base editors, and prime editors. Furthermore, this review summarizes the latest advancements in applying CRISPR/Cas genome editing systems for single gene editing in woody plants, focusing on their impact on growth, development, stress resistance, and wood or fruit quality. The potential applications of other emerging technologies, such as multi-gene editing, promoter editing, base editing, and dCas9-based activation, in improving woody plant traits are also discussed. Additionally, challenges associated with woody plant genome editing technology, such as incomplete genetic transformation systems, chimeras, off-target effects, and the risk of foreign DNA contamination in transgenic lines, are addressed along with potential solutions. While gene technology holds immense potential for enhancing woody plant genetics, it also raises concerns regarding human health and biodiversity. Therefore, comprehensive research and evaluation are necessary to ensure the safety and sustainability of gene technology in the genetic improvement of woody plants. Finally, this review presents an outlook on the potential applications of new genome editors like CRISPR/Cas13, and CRISPR/Cas14a and PE in the genetic enhancement of woody plants, aiming to provide insights for molecular design breeding efforts. In conclusion, the utilization of genome editing technology for improving woody plant genetics is a captivating field. With further advancements in science and technology, we anticipate the development of more innovative gene editors or improved delivery systems to enhance the performance of woody plants. This, in turn, will have a significant impact on enhancing key plant traits and laying the foundation for the sustainable development of forestry and horticulture.