Applications of CRISPR Technologies in Forestry and Molecular Wood Biotechnology

Abstract

Forests worldwide are under increasing pressure from climate change and emerging diseases, threatening their vital ecological and economic roles. Traditional breeding approaches, while valuable, are inherently slow and limited by the long generation times and existing genetic variation of trees. CRISPR technologies offer a transformative solution, enabling precise and efficient genome editing to accelerate the development of climate-resilient and productive forests. This review provides a comprehensive overview of CRISPR applications in forestry, exploring its potential for enhancing disease resistance, improving abiotic stress tolerance, modifying wood properties, and accelerating growth. We discuss the mechanisms and applications of various CRISPR systems, including base editing, prime editing, and multiplexing strategies. Additionally, we highlight recent advances in overcoming key challenges such as reagent delivery and plant regeneration, which are crucial for successful implementation of CRISPR in trees. We also delve into the potential and ethical considerations of using CRISPR gene drive for population-level genetic alterations, as well as the importance of genetic containment strategies for mitigating risks. This review emphasizes the need for continued research, technological advancements, extensive long-term field trials, public engagement, and responsible innovation to fully harness the power of CRISPR for shaping a sustainable future for forests.

Keywords: CRISPR/Cas9; abiotic stress; climate resilience; forest trees; genetic engineering; genome editing; pathogen resistance; tree breeding.

Figure 1

CRISPR/Cas genome editing systems. (A) CRISPR/Cas9: The gRNA guides Cas9 to the target locus, where Cas9 creates a DSB. The DSB can be repaired by NHEJ, often leading to InDel or HDR, which can be harnessed for precise gene editing. (B) Base Editors (BEs): BEs fuse a deactivated Cas9 (dCas9) to deaminase, allowing for precise single-base changes without DSBs. CBEs convert cytosine (C) to thymine (T), while ABEs convert adenine (A) to guanosine (G). Enhanced BEs incorporate a UGI (Uracil DNA glycosylase inhibitor) and a nickase Cas9 to further improve editing efficiency. (C) Prime Editors (PEs): PEs utilize a Cas9 nickase fused to a reverse transcriptase (RT) and are guided by a pegRNA that contains both targeting and editing information. The RT copies the edit from the pegRNA template and integrates it into the genome. Dual-pegRNAs targeting opposite DNA strands can further enhance editing efficiency. gRNA, guide RNA; PAM, protospacer adjacent motif; DSB, double strand break; NHEJ, non-homologous end joining; CBE, cytosine base editor; ABE, adenosine base editor; UGI, Uracil DNA glycosylase inhibitor; RTT, reverse transcriptase template; pegRNA, prime editing guide RNA.

Figure 2

Diverse applications of CRISRP technologies in forestry. CRISPR technology offers a diverse array of applications for engineering climate-resilient and productive forests, including enhancing resistance to biotic and abiotic stresses, improving wood properties, and accelerating tree growth. Targeted modifications can be identified using CRISPR-based functional genomics (studying gene function through disruption or modification) and direct evolution (generating genetic diversity and selecting for improved or novel traits). Beyond engineering trees themselves, CRISPR systems can target DNA or RNA of viral, bacterial, fungal, and oomycete species for diagnostics, pathogenicity research, or microbiome manipulation. CRISPR gene drive technology facilitates the spread of beneficial genetic modifications through plantations, while CRISPR-based genetic containment strategies help prevent the spread of engineered genes to wild populations, promoting responsible innovation.