Gene-Editing for Production Traits in Forest Trees: Challenges to Integration and Gene Target Identification

Gene-editing methods, particularly CRISPR, provide extraordinary opportunities for scientific insights and applications in the life sciences. However, prospects near-term to commercial forestry appear limited. Loss-of-function phenotypes that can be imparted by mutation of one or a few conserved genes offer best near term. For traits with complex inheritance, there is insufficient science guide gene-editing efforts, Genome-Wide Association Studies (GWASs), without strong validation, typically cannot high-confidence gene identification. Other obstacles include difficulty transformation many important genotypes, difficulties transient editing complete editor removal, complexity use breeding programs. Gene edits cause loss-of-function will generally recessive, thus not expressed among outbred progeny, so vegetative propagules (clones) required most cases. There are also societal constraints, such as strict regulations field trials countries, market certification systems do allow any kinds recombinant DNA-modified trees, including those produced gene-editing, certified production forests. We conclude extremely limited foreseeable future (i.e., at least 10 years). Nevertheless, very powerful tool widely used molecular forest scientists lead longer term, if research advances made on key fronts regulatory greatly attenuated.