Gene editing in tree and clonal crops: progress and challenges

Abstract Because of the limitations inherent in conventional breeding trees and clonally propagated crops, gene editing is great interest. Dozens published papers attest to high efficiency CRISPR-based systems clonal crops trees. The opportunity for “clean” edits expected avoid or reduce regulatory burdens many countries may improve market acceptance. To date, however, nearly all studies retained machinery genome. Despite efficiency, technical obstacles are likely greatly limit progress toward commercial use. Technical include difficult slow transformation regeneration, delayed onset flowering that make sexual segregation CRISPR-associated genes difficult, inefficient excision enable removal functional (protein- RNA-encoding) transgenic DNA, narrow host range limited gene-payload viral efficient transient editing. Regulatory those such as EU where gene-edited plants regulated like GMO forms method-based regulate stringently based on method vs. product novelty thus largely applied each insertion event. Other major provisions Cartagena Protocol with respect international trade need compliance National Environmental Policy Act USA. USDA SECURE act has taken a step more science- risk-based—vs. event based—system, but much further legal innovation needed USA beyond.