52
fertilizer, energy, medicines, cosmetics and nutraceuticals, and biotechnological,
bioremediation, and aquaculture applications with current market value of USD 7
billion (FAO 2014). 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 (PUFAs), oxylipins, and their pharmaceutical and biotechnological utilization. Most of the studies have been limited to the elucidation of lipid and fatty acid
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, a comprehensive overview of how integrating lipidomics with allied sister omics branches 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.
4.2 Seaweed Lipids
Seaweed lipids mainly consist of glycerophospholipids, saccharolipids, glycerolipids, sphingolipids, fatty acyls (including oxylipins), and sterols analogous to higher
plants along with betaine and some unusual lipids that may be characteristic of a
particular genus or species. Their chain length and degree of unsaturation are also
significantly higher than those of higher plants. The detailed structure, occurrence,
functionalities, and bioactivities of seaweed lipids have been discussed by Kumari
et al. (2013a) and recently reviewed by Maciel et al. (2016). A brief overview is
presented here.
4.2.1 Glycerophospholipids
Glycerophospholipids or phospholipids (PLs) consist of a glycerol molecule
linked with two fatty acyl chains at sn-1 and sn-2 positions and a phosphate group
at sn-3 position, which is further linked to a hydrophilic head group that classifies
P. Kumari
fertilizer, energy, medicines, cosmetics and nutraceuticals, and biotechnological,
bioremediation, and aquaculture applications with current market value of USD 7
billion (FAO 2014). 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 (PUFAs), oxylipins, and their pharmaceutical and biotechnological utilization. Most of the studies have been limited to the elucidation of lipid and fatty acid
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, a comprehensive overview of how integrating lipidomics with allied sister omics branches 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.
4.2 Seaweed Lipids
Seaweed lipids mainly consist of glycerophospholipids, saccharolipids, glycerolipids, sphingolipids, fatty acyls (including oxylipins), and sterols analogous to higher
plants along with betaine and some unusual lipids that may be characteristic of a
particular genus or species. Their chain length and degree of unsaturation are also
significantly higher than those of higher plants. The detailed structure, occurrence,
functionalities, and bioactivities of seaweed lipids have been discussed by Kumari
et al. (2013a) and recently reviewed by Maciel et al. (2016). A brief overview is
presented here.
4.2.1 Glycerophospholipids
Glycerophospholipids or phospholipids (PLs) consist of a glycerol molecule
linked with two fatty acyl chains at sn-1 and sn-2 positions and a phosphate group
at sn-3 position, which is further linked to a hydrophilic head group that classifies
P. Kumari