Potential roles of epigenetic memory on the quality of clonal cannabis plants: Content and profile of secondary metabolites

Medicinal/recreational cannabis (Cannabis sativa L.) is generally propagated using clonal techniques (stem cuttings and micropropagation) to produce genetically uniform crops. However, clones often exhibit phenotypic variation over time, becoming less vigorous with lower cannabinoid content. The source of these changes is not known but may be the result of epigenetic changes associated with maturation. Advances in multi-omics (e.g., genomics, transcriptomic, metabolomics, proteomics, epigenomics, and single-cell omics) have led to increasing discovery of various layers of biological processes. Epigenomics is one of the most important and can help us obtain a deeper understanding of gene regulatory networks in developmental phases and secondary metabolite biosynthesis pathway in cannabis. In this chapter, we discuss the main morphological and cellular changes during the life cycle of cannabis that may be related to the quality of cannabis plants. We also provide the main concepts of epigenetic machinery (e.g., nucleosome remodeling, histone modifications, small RNAs, and DNA methylation) and their possible roles in developmental phases and secondary metabolite biosynthesis pathways in cannabis.