The Potential of Novel Gene Editing-Based Approaches in Forages and Rumen Archaea for Reducing Livestock Methane Emissions

Rising emissions of anthropogenic greenhouse gases such as carbon dioxide (CO 2 ), nitrous oxide (N 2 O) and methane (CH 4 ) are a key driver of climate change, which is predicted to have myriad detrimental consequences in coming years if not kept in check. Given the potency of CH 4 in terms of trapping heat in the atmosphere in the short term, as well as the fact that ruminant production currently contributes approximately 30% of anthropogenic emissions, there is an impetus to substantially decrease the generation of ruminant-derived CH 4 . While various strategies are being assessed in this context, a multi-faceted approach is likely required to achieve significant reductions. Feed supplementation is one strategy that has shown promise in this field by attenuating methanogenesis in rumen archaea; however, this can be costly and sometimes impractical. In this review, we examine and discuss the prospect of directly modulating forages and/or rumen archaea themselves in a manner that would reduce methanogenesis using CRISPR/Cas-mediated gene editing platforms. Such an approach could provide a valuable alternative to supplementation and has the potential to contribute to the sustainability of agriculture, as well as the mitigation of climate change, in the future.