The legacy of terrestrial plant evolution on cell wall fine structure.

The evolution of land flora was an epochal event in the history of planet Earth. The success of plants, and especially flowering plants, in colonizing all but the most hostile environments required multiple mechanisms of adaptation. The mainly polysaccharide-based cell walls of flowering plants, which are indispensable for water transport and structural support, are one of the most important adaptations to life on land.

Ancient origin of fucosylated xyloglucan in charophycean green algae.

The charophycean green algae (CGA or basal streptophytes) are of particular evolutionary significance because their ancestors gave rise to land plants. One outstanding feature of these algae is that their cell walls exhibit remarkable similarities to those of land plants. Xyloglucan (XyG) is a major structural component of the cell walls of most land plants and was originally thought to be absent in CGA.

Plant Protein -Arabinosylation.

A wide range of proteins with diverse functions in development, defense, and stress responses are -arabinosylated at hydroxyprolines (Hyps) within distinct amino acid motifs of continuous stretches of Hyps, as found in the structural cell wall extensins, or at non-continuous Hyps as, for example, found in small peptide hormones and a variety of plasma membrane proteins involved in signaling. Plant -glycosylation relies on hydroxylation of Prolines to Hyps in the protein backbone, mediated by prolyl-4-hydroxylase (P4H) which is followed by -glycosylation of the Hyp C-OH group by either galactosyltransferases (GalTs) or arabinofuranosyltranferases (AraTs) yielding either Hyp-galactosylation or Hyp-arabinosylation. A subset of the P4H enzymes with putative preference to hydroxylation of continuous prolines and presumably all AraT enzymes needed for synthesis of the substituted arabinose chains of one to four arabinose units, have been identified and functionally characterized.

Analytical implications of different methods for preparing plant cell wall material.

Almost all plant cells are surrounded by a wall constructed of co-extensive networks of polysaccharides and proteoglycans. The capability to analyse cell wall components is essential for both understanding their complex biology and to fully exploit their numerous practical applications. Several biochemical and immunological techniques are used to analyse cell walls and in almost all cases the first step is the preparation of an alcohol insoluble residue (AIR).

Amylose/cellulose nanofiber composites for all-natural, fully biodegradable and flexible bioplastics.

Thermoplastic, polysaccharide-based plastics are environmentally friendly. However, typical shortcomings include lack of water resistance and poor mechanical properties. Nanocomposite manufacturing using pure, highly linear, polysaccharides can overcome such limitations.

Extensin arabinoside chain length is modulated in elongating cotton fibre.

Cotton fibre provides a unicellular model system for studying cell expansion and secondary cell wall deposition. Mature cotton fibres are mainly composed of cellulose while the walls of developing fibre cells contain a variety of polysaccharides and proteoglycans required for cell expansion. This includes hydroxyproline-rich glycoproteins (HRGPs) comprising the subgroup, extensins.

Golgi-localized exo-β1,3-galactosidases involved in cell expansion and root growth in .

Plant arabinogalactan proteins (AGPs) are a diverse group of cell surface- and wall-associated glycoproteins. Functionally important AGP glycans are synthesized in the Golgi apparatus, but the relationships among their glycosylation levels, processing, and functionalities are poorly understood. Here, we report the identification and functional characterization of two Golgi-localized exo-β-1,3-galactosidases from the glycosyl hydrolase 43 (GH43) family in GH43 loss-of-function mutants exhibited root cell expansion defects in sugar-containing growth media.

Phenolic cross-links: building and de-constructing the plant cell wall.

Covering: Up to 2019Phenolic cross-links and phenolic inter-unit linkages result from the oxidative coupling of two hydroxycinnamates or two molecules of tyrosine. Free dimers of hydroxycinnamates, lignans, play important roles in plant defence. Cross-linking of bound phenolics in the plant cell wall affects cell expansion, wall strength, digestibility, degradability, and pathogen resistance.

Sustainable production of cellulose nanofiber gels and paper from sugar beet waste using enzymatic pre-treatment.

Removal of non-cellulosic polymers from vegetable pulp to obtain cellulose nanofibers (CNF) is normally achieved by chemical pre-treatments which requires several washing steps. In the present study, it is demonstrated how incubation of sugar beet pulp at pH 9, followed by treatment with polysaccharide-degrading enzymes and subsequent bleaching can be done in a one-pot procedure to make CNF. The new method consumes 67% less water and removes non-cellulosic polysaccharides with similar efficiency as a chemical method.

Metabolism of polysaccharides in dynamic middle lamellae during cotton fibre development.

Evidence is presented that cotton fibre adhesion and middle lamella formation are preceded by cutin dilution and accompanied by rhamnogalacturonan-I metabolism. Cotton fibres are single cell structures that early in development adhere to one another via the cotton fibre middle lamella (CFML) to form a tissue-like structure. The CFML is disassembled around the time of initial secondary wall deposition, leading to fibre detachment.

Nanofibers Produced from Agro-Industrial Plant Waste Using Entirely Enzymatic Pretreatments.

Cellulose fibers can be freed from the cell-wall skeleton via high-shear homogenization, to produce cellulose nanofibers (CNF) that can be used, for example, as the reinforcing phase in composite materials. Nanofiber production from agro-industrial byproducts normally involves harsh chemical-pretreatments and high temperatures to remove noncellulosic polysaccharides (20-70% of dry weight). However, this is expensive for large-scale processing and environmentally damaging.

The Chara Genome: Secondary Complexity and Implications for Plant Terrestrialization.

Land plants evolved from charophytic algae, among which Charophyceae possess the most complex body plans. We present the genome of Chara braunii; comparison of the genome to those of land plants identified evolutionary novelties for plant terrestrialization and land plant heritage genes. C.

Identification of an algal xylan synthase indicates that there is functional orthology between algal and plant cell wall biosynthesis.

Insights into the evolution of plant cell walls have important implications for comprehending these diverse and abundant biological structures. In order to understand the evolving structure-function relationships of the plant cell wall, it is imperative to trace the origin of its different components. The present study is focused on plant 1,4-β-xylan, tracing its evolutionary origin by genome and transcriptome mining followed by phylogenetic analysis, utilizing a large selection of plants and algae.

Pea Border Cell Maturation and Release Involve Complex Cell Wall Structural Dynamics.

The adhesion of plant cells is vital for support and protection of the plant body and is maintained by a variety of molecular associations between cell wall components. In some specialized cases, though, plant cells are programmed to detach, and root cap-derived border cells are examples of this. Border cells (in some species known as border-like cells) provide an expendable barrier between roots and the environment.

Rhamnogalacturonan-I Based Microcapsules for Targeted Drug Release.

Drug targeting to the colon via the oral administration route for local treatment of e.g. inflammatory bowel disease and colonic cancer has several advantages such as needle-free administration and low infection risk.

Degradation of lignin β-aryl ether units in Arabidopsis thaliana expressing LigD, LigF and LigG from Sphingomonas paucimobilis SYK-6.

Lignin is a major polymer in the secondary plant cell wall and composed of hydrophobic interlinked hydroxyphenylpropanoid units. The presence of lignin hampers conversion of plant biomass into biofuels; plants with modified lignin are therefore being investigated for increased digestibility. The bacterium Sphingomonas paucimobilis produces lignin-degrading enzymes including LigD, LigF and LigG involved in cleaving the most abundant lignin interunit linkage, the β-aryl ether bond.

Why Plants Were Terrestrial from the Beginning.

The current hypothesis is that land plants originated from a charophycean green alga and that a prominent feature for adaptation to land was their development of alternating life cycles. Our work on cell wall evolution and morphological and physiological observations in the charophycean green algae challenged us to reassess how land plants became terrestrial. Our hypothesis is simple in that the charophycean green algae ancestors were already living on land and had been doing so for some time before the emergence of land plants.

Penium margaritaceum as a model organism for cell wall analysis of expanding plant cells.

The growth of a plant cell encompasses a complex set of subcellular components interacting in a highly coordinated fashion. Ultimately, these activities create specific cell wall structural domains that regulate the prime force of expansion, internally generated turgor pressure. The precise organization of the polymeric networks of the cell wall around the protoplast also contributes to the direction of growth, the shape of the cell, and the proper positioning of the cell in a tissue.

Pectic arabinan side chains are essential for pollen cell wall integrity during pollen development.

Pectin is a complex polysaccharide and an integral part of the primary plant cell wall and middle lamella, contributing to cell wall mechanical strength and cell adhesion. To understand the structure-function relationships of pectin in the cell wall, a set of transgenic potato lines with altered pectin composition was analysed. The expression of genes encoding enzymes involved in pectin acetylation, degradation of the rhamnogalacturonan backbone and type and length of neutral side chains, arabinan and galactan in particular, has been altered.

Classification, naming and evolutionary history of glycosyltransferases from sequenced green and red algal genomes.

The Archaeplastida consists of three lineages, Rhodophyta, Virideplantae and Glaucophyta. The extracellular matrix of most members of the Rhodophyta and Viridiplantae consists of carbohydrate-based or a highly glycosylated protein-based cell wall while the Glaucophyte covering is poorly resolved. In order to elucidate possible evolutionary links between the three advanced lineages in Archaeplastida, a genomic analysis was initiated.