Seaweed lipidomics in the era of ‘omics’ biology: A contemporary perspective

Lipidomics, a branch of “omic” sciences, refers to the analysis of lipids on the systems level together with their interacting factors including expression of proteins involved in lipid metabolism and function and gene regulation. Seaweeds are one of the important ecosystem drivers that inhabit an unique aquatic environment being exposed to a diverse range of environmental fluctuations (salinity, light, desiccation, and temperature), pathogens, invasive species, and anthropogenic factors that affect their phenotype as well as acclimatory strategies. As a result of thriving in such diverse and extreme environments, they produce an array of unique bioactive, complex, exotic acyl lipids and fatty acids that are not generally present in terrestrial plants. Seaweeds have been extensively studied for their bioactive lipids mainly for their nutritionally important polyunsaturated fatty acids, oxylipins, and their pharmaceutical and biotechnological utilization. Most of the studies have been limited to the elucidation of lipid and fatty acids composition, their metabolic pathways, the genes and enzymes involved, as well as their roles in stress responses, innate immunity, and defense against pathogens. Although lipidomics has been extensively used in terrestrial plants and even microalgae to unravel their lipidome, functional annotation of unknown genes involved in lipid metabolism, correlation of genotype-phenotype, and understanding of the pleiotropic roles of lipids in cell development and biotic/abiotic stresses, only a few seaweeds have been studied with lipidomic approach. This chapter presents updated information on lipidomics, advanced analytical tools and techniques, and their applicability in seaweed studies along with its limitations. Further, an overview of how integrating lipidomics with allied sister branches of metabolomics, transcriptomics, and proteomics can help in the identification of unknown gene/protein functions and development of systems biology networks advancing our knowledge of lipid biochemistry in seaweed development and acclimation to stress conditions are discussed.