Plant and algal lipidomes: Analysis, composition, and their societal significance.

Plants and algae play a crucial role in the earth's ecosystems. Through photosynthesis they convert light energy into chemical energy, capture CO2 and produce oxygen and energy-rich organic compounds. Photosynthetic organisms are primary producers and synthesize the essential omega 3 and omega 6 fatty acids.

Morphology and chemical composition of Taiwan oil millet (Eccoilopus formosanus) epicuticular wax.

Taiwan oil millet has two types of epicuticular wax: platelet wax composed primarily of octacosanol and filament wax constituted essentially by the singular compound of octacosanoic acid. Taiwan oil millet (TOM-Eccoilopus formosanus) is an orphan crop cultivated by the Taiwan indigenous people. It has conspicuous white powder covering its leaf sheath indicating abundant epicuticular waxes, that may contribute to its resilience.

Characterization of Unique Eukaryotic Sphingolipids with Temperature-Dependent Δ8-Unsaturation from the Picoalga Ostreococcus tauri.

Sphingolipids (SLs) are ubiquitous components of eukaryotic cell membranes and are found in some prokaryotic organisms and viruses. They are composed of a sphingoid backbone that may be acylated and glycosylated. Assembly of various sphingoid base, fatty acyl and glycosyl moieties results in highly diverse structures.

Tackling functional redundancy of Arabidopsis fatty acid elongase complexes.

Very-long-chain fatty acids (VLCFA) are precursors for various lipids playing important physiological and structural roles in plants. Throughout plant tissues, VLCFA are present in multiple lipid classes essential for membrane homeostasis, and also stored in triacylglycerols. VLCFA and their derivatives are also highly abundant in lipid barriers, such as cuticular waxes in aerial epidermal cells and suberin monomers in roots.

The production of wax esters in transgenic plants: towards a sustainable source of bio-lubricants.

Wax esters are high-value compounds used as feedstocks for the production of lubricants, pharmaceuticals, and cosmetics. Currently, they are produced mostly from fossil reserves using chemical synthesis, but this cannot meet increasing demand and has a negative environmental impact. Natural wax esters are also obtained from Simmondsia chinensis (jojoba) but comparably in very low amounts and expensively.

Biosynthesis and Functions of Very-Long-Chain Fatty Acids in the Responses of Plants to Abiotic and Biotic Stresses.

Very-long-chain fatty acids (i.e., fatty acids with more than 18 carbon atoms; VLCFA) are important molecules that play crucial physiological and structural roles in plants.

Temperature Acclimation of the Picoalga Triggers Early Fatty-Acid Variations and Involves a Plastidial ω3-Desaturase.

Alteration of fatty-acid unsaturation is a universal response to temperature changes. Marine microalgae display the largest diversity of polyunsaturated fatty-acid (PUFA) whose content notably varies according to temperature. The physiological relevance and the molecular mechanisms underlying these changes are however, still poorly understood.

Multi-Approach Analysis Reveals Local Adaptation in a Widespread Forest Tree of Reunion Island.

Detecting processes of local adaptation in forest trees and identifying environmental selective drivers are of primary importance for forest management and conservation. Transplant experiments, functional genomics and population genomics are complementary tools to efficiently characterize heritable phenotypic traits and to decipher the genetic bases of adaptive traits. Using an integrative approach combining phenotypic assessment in common garden, transcriptomics and landscape genomics, we investigated leaf adaptive traits in Coffea mauritiana, a forest tree endemic to Reunion Island.

Drought activates MYB41 orthologs and induces suberization of grapevine fine roots.

The permeability of roots to water and nutrients is controlled through a variety of mechanisms and one of the most conspicuous is the presence of the Casparian strips and suberin lamellae. Roots actively regulate the creation of these structures developmentally, along the length of the root, and in response to the environment, including drought. In the current study, we characterized the suberin composition along the length of grapevine fine roots during development and in response to water deficit, and in the same root systems we quantified changes in expression of suberin biosynthesis- and deposition-related gene families (via RNAseq) allowing the identification of drought-responsive suberin-related genes.

Differential Activation of Partially Redundant Δ9 Stearoyl-ACP Desaturase Genes Is Critical for Omega-9 Monounsaturated Fatty Acid Biosynthesis During Seed Development in Arabidopsis.

The spatiotemporal pattern of deposition, final amount, and relative abundance of oleic acid (-ω-9 C18:1) and its derivatives in the different lipid fractions of the seed of Arabidopsis () indicates that omega-9 monoenes are synthesized at high rates in this organ. Accordingly, we observed that four Δ9 stearoyl-ACP desaturase (SAD)-coding genes ( [], [], , and ) are transcriptionally induced in seeds. We established that the three most highly expressed ones are directly activated by the WRINKLED1 transcription factor.

Plastidic Δ6 Fatty-Acid Desaturases with Distinctive Substrate Specificity Regulate the Pool of C18-PUFAs in the Ancestral Picoalga .

Eukaryotic Δ6-desaturases are microsomal enzymes that balance the synthesis of ω-3 and ω-6 C18-polyunsaturated fatty acids (C18-PUFAs) according to their specificity. In several microalgae, including , plastidic C18-PUFAs are strictly regulated by environmental cues suggesting an autonomous control of Δ6-desaturation of plastidic PUFAs. Here, we identified two putative front-end Δ6/Δ8-desaturases from that, together with putative homologs, cluster apart from other characterized Δ6-desaturases.

Drought-Responsive Regulates Cuticle Biosynthesis and Cuticle-Dependent Leaf Permeability.

In all land plants, the outer surface of aerial parts is covered by the cuticle, a complex lipid layer that constitutes a barrier against damage caused by environmental factors and provides protection against nonstomatal water loss. We show in this study that both cuticle deposition and cuticle-dependent leaf permeability during the juvenile phase of plant development are controlled by the maize () transcription factor ZmFUSED LEAVES 1 (FDL1)/MYB94. Biochemical analysis showed altered cutin and wax biosynthesis and deposition in mutant seedlings at the coleoptile stage.

Characterization and heterologous expression of three DGATs from oil palm (Elaeis guineensis) mesocarp in Saccharomyces cerevisiae.

Oil palm (Elaeis guineensis) can accumulate up to 88% oil in fruit mesocarp. A previous transcriptome study of oil palm fruits indicated that genes coding for three diacylglycerol acyltransferases (DGATs), designated as EgDGAT1_3, EgDGAT2_2 and EgWS/DGAT_1 (according to Rosli et al., 2018) were highly expressed in mesocarp during oil accumulation.

Deposition of a cutin apoplastic barrier separating seed maternal and zygotic tissues.

Background: In flowering plants, proper seed development is achieved through the constant interplay of fertilization products, embryo and endosperm, and maternal tissues. Communication between these compartments is supposed to be tightly regulated at their interfaces. Here, we characterize the deposition pattern of an apoplastic lipid barrier between the maternal inner integument and fertilization products in Arabidopsis thaliana seeds.

A stress-response-related inter-compartmental signalling pathway regulates embryonic cuticle integrity in Arabidopsis.

The embryonic cuticle is necessary for normal seed development and seedling establishment in Arabidopsis. Although mutants with defective embryonic cuticles have been identified, neither the deposition of cuticle material, nor its regulation, has been described during embryogenesis. Here we use electron microscopy, cuticle staining and permeability assays to show that cuticle deposition initiates de novo in patches on globular embryos.

Arabidopsis CER1-LIKE1 Functions in a Cuticular Very-Long-Chain Alkane-Forming Complex.

Plant aerial organs are coated with cuticular waxes, a hydrophobic layer that primarily serves as a waterproofing barrier. Cuticular wax is a mixture of aliphatic very-long-chain molecules, ranging from 22 to 48 carbons, produced in the endoplasmic reticulum of epidermal cells. Among all wax components, alkanes represent up to 80% of total wax in Arabidopsis () leaves.

Wax synthase MhWS2 from Marinobacter hydrocarbonoclasticus: substrate specificity and biotechnological potential for wax ester production.

Wax synthases are involved in the biosynthesis of wax esters, lipids with great industrial potential. Here, we heterologously expressed the native wax synthase MhWS2 from Marinobacter hydrocarbonoclasticus in Saccharomyces cerevisiae and performed comprehensive analysis of its substrate specificity. The enzyme displayed high wax synthase (but no diacylglycerol acyltransferase) activity both in vivo and in vitro.

Intracellular Distribution of Manganese by the -Golgi Network Transporter NRAMP2 Is Critical for Photosynthesis and Cellular Redox Homeostasis.

Plants require trace levels of manganese (Mn) for survival, as it is an essential cofactor in oxygen metabolism, especially O production via photosynthesis and the disposal of superoxide radicals. These processes occur in specialized organelles, requiring membrane-bound intracellular transporters to partition Mn between cell compartments. We identified an member of the NRAMP family of divalent metal transporters, NRAMP2, which functions in the intracellular distribution of Mn.

Qualitative and quantitative study of the highly specialized lipid tissues of cetaceans using HR-MAS NMR and classical GC.

Cetacean adipose tissues contain an extremely very wide variety of acyl-chains present in triacylglycerols and / or wax esters. In addition, changes in the lipid composition across organs suggest fine stratification. It therefore remains technically challenging to describe precisely the lipid organization of these tissues.

Occurrence and Biosynthesis of Alkyl Hydroxycinnamates in Plant Lipid Barriers.

The plant lipid barriers cuticle and suberin represent one of the largest biological interfaces on the planet. They are comprised of an insoluble polymeric domain with associated organic solvent-soluble waxes. Suberin-associated and plant cuticular waxes contain mixtures of aliphatic components that may include alkyl hydroxycinnamates (AHCs).

Root Aliphatic Suberin Analysis Using Non-extraction or Solvent-extraction Methods.

Here we describe both non-extraction and solvent-extraction methods for root aliphatic suberin analysis. The non-extraction method is fast as roots are directly depolymerized using acidic transmethylation. However, suberin aliphatic components are isolated together with all the other acyl chains making up the lipids (, membranes) present in roots.

The Lipid Transfer Protein 2 (AtLTP2) Is Involved in Cuticle-Cell Wall Interface Integrity and in Etiolated Hypocotyl Permeability.

Plant non-specific lipid transfer proteins (nsLTPs) belong to a complex multigenic family implicated in diverse physiological processes. However, their function and mode of action remain unclear probably because of functional redundancy. Among the different roles proposed for nsLTPs, it has long been suggested that they could transport cuticular precursor across the cell wall during the formation of the cuticle, which constitutes the first physical barrier for plant interactions with their aerial environment.

Enrichment of hydroxylated C24- and C26-acyl-chain sphingolipids mediates PIN2 apical sorting at trans-Golgi network subdomains.

The post-Golgi compartment trans-Golgi Network (TGN) is a central hub divided into multiple subdomains hosting distinct trafficking pathways, including polar delivery to apical membrane. Lipids such as sphingolipids and sterols have been implicated in polar trafficking from the TGN but the underlying mechanisms linking lipid composition to functional polar sorting at TGN subdomains remain unknown. Here we demonstrate that sphingolipids with α-hydroxylated acyl-chains of at least 24 carbon atoms are enriched in secretory vesicle subdomains of the TGN and are critical for de novo polar secretory sorting of the auxin carrier PIN2 to apical membrane of Arabidopsis root epithelial cells.