85
based targeted oxylipin profiling was used to study activated chemical defense
induced by increased production of PGE 2 and related toxic lipid compounds in
non- native populations of G. vermiculophylla (Hammann et al. 2016). These
authors reported that wounding of non-native seaweed populations of G. vermiculophylla resulted in approximately 390% more production of 15-keto-PGE 2 , 90%
more PGE 2 , 37% more PGA 2 , and 96% more 7,8-di-HETE than wounding of
native populations. PGE 2 , PGA 2 , and 7,8-di-HETE are known to deter various
biological enemies of G. vermiculophylla that cause tissue or cell wounding, and
also repelled the mesograzer Littorina brevicula, indicating that non-native populations of G. vermiculophylla were more defended against herbivory than native
populations. This increased capacity for activated chemical defense may be the
reason behind their invasive success.
4.6 Integration of Lipidomics with Allied Omics Platforms
Integration of lipidomics with other allied omics (genomics, transcriptomics, proteomics, and metabolomics) platforms offers promising tool to practice systems
biology to identify novel genes, enzymes, and lipid metabolic pathways to
increase our comprehension of seaweed lipid biochemistry and the role of novel
lipid molecules in combating different biotic/abiotic stresses. With the accessibility of whole genome sequences, next-generation mass spectrometers, and
advanced bioinformatic tools, lipidomics has assumed a prominent role in systems biology studies through its unique ability to directly identify functional
alterations in multiple lipid metabolic and signaling networks. systems biology is
an interdisciplinary approach integrating data from different omics disciplines
into numerical models with the aim to simulate the physiology of the organism
(Kumar et al. 2016). Recently, Loizides- Mangold (2013) proposed a new term
“systematic lipidomics” which combines different pathway analyses with
MS-based lipidomics. Systematic lipidomics aims to investigate how the perturbance of one pathway influences the lipidome of cells. Pathway targeting in the
context of lipid analysis will lead to an increase or decrease in certain lipid metabolites, either directly or indirectly through a cascade of signaling events. There
are two approaches in systematic lipidomics: hypothesis-driven approach and
data-driven approach (Fig. 4.4). In hypothesis-driven approach, prior knowledge
is used to select a pathway hypothesized to have a lipid phenotype. In the datadriven approach, large-scale sets of biological pathways are selected to uncover
novel pathway-lipid phenotype relationships and are supported by pathway analysis of genomic data or metabolite pathway enrichment analysis (LoizidesMangold 2013).
The full genomes and characterization of key genetic pathways driving metabolism of model seaweeds have focused the direction of most of the omics studies
toward model seaweeds Ectocarpus, Chondrus, Pyropia, and Saccharina. Most of the
4 Seaweed Lipidomics in the Era of ‘Omics’ Biology: A Contemporary Perspective
based targeted oxylipin profiling was used to study activated chemical defense
induced by increased production of PGE 2 and related toxic lipid compounds in
non- native populations of G. vermiculophylla (Hammann et al. 2016). These
authors reported that wounding of non-native seaweed populations of G. vermiculophylla resulted in approximately 390% more production of 15-keto-PGE 2 , 90%
more PGE 2 , 37% more PGA 2 , and 96% more 7,8-di-HETE than wounding of
native populations. PGE 2 , PGA 2 , and 7,8-di-HETE are known to deter various
biological enemies of G. vermiculophylla that cause tissue or cell wounding, and
also repelled the mesograzer Littorina brevicula, indicating that non-native populations of G. vermiculophylla were more defended against herbivory than native
populations. This increased capacity for activated chemical defense may be the
reason behind their invasive success.
4.6 Integration of Lipidomics with Allied Omics Platforms
Integration of lipidomics with other allied omics (genomics, transcriptomics, proteomics, and metabolomics) platforms offers promising tool to practice systems
biology to identify novel genes, enzymes, and lipid metabolic pathways to
increase our comprehension of seaweed lipid biochemistry and the role of novel
lipid molecules in combating different biotic/abiotic stresses. With the accessibility of whole genome sequences, next-generation mass spectrometers, and
advanced bioinformatic tools, lipidomics has assumed a prominent role in systems biology studies through its unique ability to directly identify functional
alterations in multiple lipid metabolic and signaling networks. systems biology is
an interdisciplinary approach integrating data from different omics disciplines
into numerical models with the aim to simulate the physiology of the organism
(Kumar et al. 2016). Recently, Loizides- Mangold (2013) proposed a new term
“systematic lipidomics” which combines different pathway analyses with
MS-based lipidomics. Systematic lipidomics aims to investigate how the perturbance of one pathway influences the lipidome of cells. Pathway targeting in the
context of lipid analysis will lead to an increase or decrease in certain lipid metabolites, either directly or indirectly through a cascade of signaling events. There
are two approaches in systematic lipidomics: hypothesis-driven approach and
data-driven approach (Fig. 4.4). In hypothesis-driven approach, prior knowledge
is used to select a pathway hypothesized to have a lipid phenotype. In the datadriven approach, large-scale sets of biological pathways are selected to uncover
novel pathway-lipid phenotype relationships and are supported by pathway analysis of genomic data or metabolite pathway enrichment analysis (LoizidesMangold 2013).
The full genomes and characterization of key genetic pathways driving metabolism of model seaweeds have focused the direction of most of the omics studies
toward model seaweeds Ectocarpus, Chondrus, Pyropia, and Saccharina. Most of the
4 Seaweed Lipidomics in the Era of ‘Omics’ Biology: A Contemporary Perspective