Cell wall-related glycosyltransferases and wall architecture in the model liverwort Marchantia polymorpha.

The liverwort Marchantia polymorpha has emerged as an important plant model for developmental studies and may become central to elucidate the complex process of cell wall polysaccharide biosynthesis. This study comprehensively analyses the composition and structure of cell wall glycans across eight different M. polymorpha tissue types.

Galactan mobilization during carbon starvation compromises plant cell wall-mediated resistance to fungal infection.

Polysaccharides are the main components present in plant cell walls. They form a network that is dynamically modified during growth and upon both abiotic and biotic stress. We investigated how the cell wall of Arabidopsis rosettes is remodeled during periods of dark-induced starvation in the wild type and in plastidic phosphoglucomutase (pgm) mutants, which suffer from periodic starvation due to starch deficiency.

Nucleotide Sugar Transporters: Orchestrating Luminal Glycosylation in Plants.

Eukaryotic glycobiology revolves around nucleotide sugar transporters (NSTs), which are critical for glycan biosynthesis in the Golgi apparatus and endoplasmic reticulum. In plants, NSTs share similarities with triose phosphate translocators (TPTs) and together form the NST/TPT superfamily. Major research efforts over the last decades have led to the biochemical characterization of several of these transporters and addressed their role in cell wall polysaccharide and glycoconjugate biosynthesis, revealing precise substrate specificity and function.

Control of sporophyte secondary cell wall development in Marchantia by a Class II KNOX gene.

Land plants evolved from an ancestral alga around 470 mya, evolving complex multicellularity in both haploid gametophyte and diploid sporophyte generations. The evolution of water-conducting tissues in the sporophyte generation was crucial for the success of land plants, paving the way for the colonization of a variety of terrestrial habitats. Class II KNOX (KNOX2) genes are major regulators of secondary cell wall formation and seed mucilage (pectin) deposition in flowering plants.

NKS1/ELMO4 is an integral protein of a pectin synthesis protein complex and maintains Golgi morphology and cell adhesion in .

Adjacent plant cells are connected by specialized cell wall regions, called middle lamellae, which influence critical agricultural characteristics, including fruit ripening and organ abscission. Middle lamellae are enriched in pectin polysaccharides, specifically homogalacturonan (HG). Here, we identify a plant-specific DUF1068 protein, called NKS1/ELMO4, that is required for middle lamellae integrity and cell adhesion.

Comparative genomics points to tandem duplications of SAD gene clusters as drivers of increased α-linolenic (ω-3) content in S. hispanica seeds.

Salvia hispanica L. (chia) is a source of abundant ω-3 polyunsaturated fatty acids (ω-3-PUFAs) that are highly beneficial to human health. The genomic basis for this accrued ω-3-PUFA content in this emerging crop was investigated through the assembly and comparative analysis of a chromosome-level reference genome for S.

Balanced callose and cellulose biosynthesis in Arabidopsis quorum-sensing signaling and pattern-triggered immunity.

The plant cell wall (CW) is one of the most important physical barriers that phytopathogens must conquer to invade their hosts. This barrier is a dynamic structure that responds to pathogen infection through a complex network of immune receptors, together with CW-synthesizing and CW-degrading enzymes. Callose deposition in the primary CW is a well-known physical response to pathogen infection.

The state of the art in plant lipidomics.

Lipids are a group of compounds with diverse structures that perform several important functions in plants. To unravel and better understand their functions, plant biologists have been using various lipidomic technologies including liquid-chromatography (LC)-mass spectrometry (MS). However, there are still significant challenges in LC-MS based plant lipidomics, which need to be addressed.

Cell surface carbohydrates of symbiotic dinoflagellates and their role in the establishment of cnidarian-dinoflagellate symbiosis.

Symbiodiniaceae algae are often photosymbionts of reef-building corals. The establishment of their symbiosis resembles a microbial infection where eukaryotic pattern recognition receptors (e.g.

Not Just a Simple Sugar: Arabinose Metabolism and Function in Plants.

Growth, development, structure as well as dynamic adaptations and remodeling processes in plants are largely controlled by properties of their cell walls. These intricate wall structures are mostly made up of different sugars connected through specific glycosidic linkages but also contain many glycosylated proteins. A key plant sugar that is present throughout the plantae, even before the divergence of the land plant lineage, but is not found in animals, is l-arabinose (l-Ara).

An Arabidopsis lipid map reveals differences between tissues and dynamic changes throughout development.

Mass spectrometry is the predominant analytical tool used in the field of plant lipidomics. However, there are many challenges associated with the mass spectrometric detection and identification of lipids because of the highly complex nature of plant lipids. Studies into lipid biosynthetic pathways, gene functions in lipid metabolism, lipid changes during plant growth and development, and the holistic examination of the role of plant lipids in environmental stress responses are often hindered.

A comprehensive comparison of four methods for extracting lipids from Arabidopsis tissues.

Background: The plant lipidome is highly complex, and the composition of lipids in different tissues as well as their specific functions in plant development, growth and stress responses have yet to be fully elucidated. To do this, efficient lipid extraction protocols which deliver target compounds in solution at concentrations adequate for subsequent detection, quantitation and analysis through spectroscopic methods are required. To date, numerous methods are used to extract lipids from plant tissues.

UDP-Api/UDP-Xyl synthases affect plant development by controlling the content of UDP-Api to regulate the RG-II-borate complex.

Rhamnogalacturonan-II (RG-II) is structurally the most complex glycan in higher plants, containing 13 different sugars and 21 distinct glycosidic linkages. Two monomeric RG-II molecules can form an RG-II-borate diester dimer through the two apiosyl (Api) residues of side chain A to regulate cross-linking of pectin in the cell wall. But the relationship of Api biosynthesis and RG-II dimer is still unclear.

A hypomorphic allele of SLC35D1 results in Schneckenbecken-like dysplasia.

We report the case of a consanguineous couple who lost four pregnancies associated with skeletal dysplasia. Radiological examination of one fetus was inconclusive. Parental exome sequencing showed that both parents were heterozygous for a novel missense variant, p.

Profiling Cell Wall Monosaccharides and Nucleotide-Sugars from Plants.

The cell wall is an intricate mesh largely composed of polysaccharides that vary in structure and abundance. Apart from cellulose biosynthesis, the assembly of matrix polysaccharides such as pectin and hemicellulose occur in the Golgi apparatus before being transported via vesicles to the cell wall. Matrix polysaccharides are biosynthesized from activated precursors or nucleotide sugars.

Conserved Glu-47 and Lys-50 residues are critical for UDP--acetylglucosamine/UMP antiport activity of the mouse Golgi-associated transporter Slc35a3.

Nucleotide sugar transporters (NSTs) regulate the flux of activated sugars from the cytosol into the lumen of the Golgi apparatus where glycosyltransferases use them for the modification of proteins, lipids, and proteoglycans. It has been well-established that NSTs are antiporters that exchange nucleotide sugars with the respective nucleoside monophosphate. Nevertheless, information about the molecular basis of ligand recognition and transport is scarce.

A Golgi UDP-GlcNAc transporter delivers substrates for N-linked glycans and sphingolipids.

Glycosylation requires activated glycosyl donors in the form of nucleotide sugars to drive processes such as post-translational protein modifications and glycolipid and polysaccharide biosynthesis. Most of these reactions occur in the Golgi, requiring cytosolic-derived nucleotide sugars, which need to be actively transferred into the Golgi lumen by nucleotide sugar transporters. We identified a Golgi-localized nucleotide sugar transporter from Arabidopsis thaliana with affinity for UDP-N-acetyl-D-glucosamine (UDP-GlcNAc) and assigned it UDP-GlcNAc transporter 1 (UGNT1).

The Three Members of the Arabidopsis Glycosyltransferase Family 92 are Functional β-1,4-Galactan Synthases.

Pectin is a major component of primary cell walls and performs a plethora of functions crucial for plant growth, development and plant-defense responses. Despite the importance of pectic polysaccharides their biosynthesis is poorly understood. Several genes have been implicated in pectin biosynthesis by mutant analysis, but biochemical activity has been shown for very few.

Gene stacking of multiple traits for high yield of fermentable sugars in plant biomass.

Background: Second-generation biofuels produced from biomass can help to decrease dependency on fossil fuels, bringing about many economic and environmental benefits. To make biomass more suitable for biorefinery use, we need a better understanding of plant cell wall biosynthesis. Increasing the ratio of C6 to C5 sugars in the cell wall and decreasing the lignin content are two important targets in engineering of plants that are more suitable for downstream processing for second-generation biofuel production.

Three UDP-xylose transporters participate in xylan biosynthesis by conveying cytosolic UDP-xylose into the Golgi lumen in Arabidopsis.

UDP-xylose (UDP-Xyl) is synthesized by UDP-glucuronic acid decarboxylases, also termed UDP-Xyl synthases (UXSs). The Arabidopsis genome encodes six UXSs, which fall into two groups based upon their subcellular location: the Golgi lumen and the cytosol. The latter group appears to play an important role in xylan biosynthesis.

Absolute Quantitation of In Vitro Expressed Plant Membrane Proteins by Targeted Proteomics (MRM) for the Determination of Kinetic Parameters.

The purification of a functional soluble protein from biological or in vitro expression systems can be problematic and the enrichment of a functional membrane protein for biochemical analyses can be a serious technical challenge. Recently we have been characterizing plant endomembrane nucleotide sugar transporters using a yeast expression system. However, rather than enriching these in vitro expressed proteins to homogeneity, we have been conducting biochemical characterization of these transport proteins in yeast microsomal fractions.

The elaborate route for UDP-arabinose delivery into the Golgi of plants.

In plants, L-arabinose (Ara) is a key component of cell wall polymers, glycoproteins, as well as flavonoids, and signaling peptides. Whereas the majority of Ara found in plant glycans occurs as a furanose ring (Ara), the activated precursor has a pyranose ring configuration (UDP-Ara). The biosynthesis of UDP-Ara mainly occurs via the epimerization of UDP-xylose (UDP-Xyl) in the Golgi lumen.

UUAT1 Is a Golgi-Localized UDP-Uronic Acid Transporter That Modulates the Polysaccharide Composition of Arabidopsis Seed Mucilage.

UDP-glucuronic acid (UDP-GlcA) is the precursor of many plant cell wall polysaccharides and is required for production of seed mucilage. Following synthesis in the cytosol, it is transported into the lumen of the Golgi apparatus, where it is converted to UDP-galacturonic acid (UDP-GalA), UDP-arabinose, and UDP-xylose. To identify the Golgi-localized UDP-GlcA transporter, we screened mutants in genes coding for putative nucleotide sugar transporters for altered seed mucilage, a structure rich in the GalA-containing polysaccharide rhamnogalacturonan I.