Summary:
The red alga Palmaria palmata ("dulse"; Palmariaceae, Rhodophyta) has been used as food since the fifth century, especially in the North Atlantic region. Dulse is a good alternative to cereals due to its high content nutritional profile. A critical review based on scientific and gray literature of dulse bioactive compounds and their activity identified key knowledge gaps. The review synthesis emphasizes the importance of species delimitation, microbial community characterization and multi-omics in the research of P. palmata. Recent advances and uncertainty in delimiting P. palmata are introduced in a phylogenetic context, and recommendations are given for the future phytochemicals studies. We refer to the concept of "seaweed holobiont" as the functional entity encompassing the seaweed and its associated microbiota, and call for action to characterize the microbial communities, since their interactions with the environment and seaweed are important in seaweed well-being and postharvest quality changes (eg microbial spoilage and degradation of algal matrices). Finally, we discuss the status and trends of using multi-omics to address important research questions P. palmata, and to help us understand the source, biosynthesis and function of it bioactive compounds.