Populus salicinoids: a thriving subfield in the omics era

Members of the salicaceous genus Populus are primarily used by plant biologists as a model system for understanding the genetic underpinnings of woody plant growth and development. Beyond their importance to those conducting developmental research, Populus spp. are key members of ecosystems in the Northern Hemisphere and show promise as a vital renewable source of biomass for sustainable biofuel production. This genus also produces a class of signature herbivore-deterring and medicinally significant phenolic glycosides, commonly referred to as salicinoids. Although salicinoids in Populus are primarily associated with defense against biotic disturbances, they have also been implicated in structuring the chemotaxonomy of Populus and Salicaceae, shaping endophytic microbiomes, directing abiotic stress responses and participating in primary metabolism. Despite advancements in understanding these interactions through functional genomics and biotechnological techniques such as CRISPR/Cas9, much about their function and biosynthesis still remains obfuscated. Here, we summarize a global view of progress made in Populus salicinoid research, focusing particularly on studies conducted through a biotechnological lens, to elucidate the distribution, ecological significance, and biosynthesis of these compounds.