Deepening the Role of Pectin in the Tissue Assembly Process During Tomato Grafting.

Cell walls play essential roles in cell recognition, tissue adhesion, and wound response. In particular, pectins as cell-adhesive agents are expected to play a key role in the early stages of grafting. To test this premise, this study focused on examining the dynamics of the accumulation and degree of methyl-esterification of pectic polysaccharides at the graft junctions using tomato autografts as an experimental model.

Mucilicious methods: Navigating the tools developed to Arabidopsis Seed Coat Mucilage analysis.

During the last decades, Arabidopsis seed mucilage has been extensively studied to gain insight into the metabolism of pectin, hemicellulose and cellulose. This review aims to provide a comprehensive examination of the techniques used to understand the composition and structure of mucilage. Moreover, we present novel findings from mucilage analysis, including the separation of pectic domains within the mucilage, offering a fresh perspective on utilizing traditional techniques to analyze mucilage mutant lines.

Unraveling cell wall polysaccharides during blueberry ripening: insights into the roles of rhamnogalacturonan-I and arabinogalactan proteins in fruit firmness.

Blueberries () undergo significant texture changes during development and ripening, notably a consistent decrease in firmness, which affects fruit quality, consumer preference, transportability, and shelf life. This study examined the composition and structural modifications of the cell wall in five commercially available blueberry varieties with differing firmness levels at harvest. Our approach integrated various biochemical techniques for a comprehensive analysis of cell wall components to elucidate firmness differences at the harvest stage.

Mucilage extracted from Chilean papaya seeds is enriched with homogalacturonan domains.

Chilean papaya, also known as mountain papaya (), is a fruit valued for its nutritional value and pleasant fragrance. The oblong fruit, featuring five ridges and a seed-filled mucilage cavity, is typically consumed cooked due to its high protease content. The mucilage and the seeds are usually discarded as byproducts.

A novel pectin methylesterase inhibitor, PMEI3, in common bean suggests a key role of pectin methylesterification in Pseudomonas resistance.

The mechanisms underlying susceptibility to and defense against Pseudomonas syringae (Pph) of the common bean (Phaseolus vulgaris) have not yet been clarified. To investigate these, 15-day-old plants of the variety Riñón were infected with Pph and the transcriptomic changes at 2 h and 9 h post-infection were analysed. RNA-seq analysis showed an up-regulation of genes involved in defense/signaling at 2 h, most of them being down-regulated at 9 h, suggesting that Pph inhibits the transcriptomic reprogramming of the plant.

s are required for pectin methyl-esterification and mucilage release in seed coat epidermal cells.

Introduction: play a role in the methylation of polysaccharides synthesized by the Golgi. Pectin homogalacturonan (HG) methyl-esterification is essential for the proper function of this polysaccharide in cell walls. In order to better understand the role of in HG biosynthesis, we analyzed mucilage methyl-esterification in mutants.

Rhamnogalacturonan-I forms mucilage: behind its simplicity, a cutting-edge organization.

. 2022. The Class II KNOX family members and redundantly participate in Arabidopsis seed coat mucilage biosynthesis.

Golgi-localized putative S-adenosyl methionine transporters required for plant cell wall polysaccharide methylation.

Polysaccharide methylation, especially that of pectin, is a common and important feature of land plant cell walls. Polysaccharide methylation takes place in the Golgi apparatus and therefore relies on the import of S-adenosyl methionine (SAM) from the cytosol into the Golgi. However, so far, no Golgi SAM transporter has been identified in plants.

Pre-Anthesis Cytokinin Applications Increase Table Grape Berry Firmness by Modulating Cell Wall Polysaccharides.

The use of plant growth regulators (PGRs) is widespread in commercial table grape vineyards. The synthetic cytokinin CPPU is a PGR that is extensively used to obtain higher quality grapes. However, the effect of CPPU on berry firmness is not clear.

Transport of UDP-rhamnose by URGT2, URGT4, and URGT6 modulates rhamnogalacturonan-I length.

Rhamnogalacturonan-I biosynthesis occurs in the lumen of the Golgi apparatus, a compartment where UDP-Rhamnose and UDP-Galacturonic Acid are the main substrates for synthesis of the backbone polymer of pectin. Recent studies showed that UDP-Rha is transported from the cytosol into the Golgi apparatus by a family of six UDP-rhamnose/UDP-galactose transporters (URGT1-6). In this study, analysis of adherent and soluble mucilage (SM) of Arabidopsis thaliana seeds revealed distinct roles of URGT2, URGT4, and URGT6 in mucilage biosynthesis.

Functional Interchangeability of Nucleotide Sugar Transporters URGT1 and URGT2 Reveals That and Cell Wall Chemotypes Depend on Their Spatio-Temporal Expression.

Nucleotide sugar transporters (NSTs) are Golgi-localized proteins that play a role in polysaccharide biosynthesis by transporting substrates (nucleotide sugars) from the cytosol into the Golgi apparatus. In Arabidopsis, there is an NST subfamily of six members, called URGTs, which transport UDP-rhamnose and UDP-galactose . URGTs are very similar in protein sequences, and among them, URGT1 and URGT2 are highly conserved in protein sequence and also showed very similar kinetic parameters toward UDP-rhamnose and UDP-galactose .

New steps in mucilage biosynthesis revealed by analysis of the transcriptome of the UDP-rhamnose/UDP-galactose transporter 2 mutant.

Upon imbibition, epidermal cells of Arabidopsis thaliana seeds release a mucilage formed mostly by pectic polysaccharides. The Arabidopsis mucilage is composed mainly of unbranched rhamnogalacturonan-I (RG-I), with low amounts of cellulose, homogalacturonan, and traces of xylan, xyloglucan, galactoglucomannan, and galactan. The pectin-rich composition of the mucilage and their simple extractability makes this structure a good candidate to study the biosynthesis of pectic polysaccharides and their modification.

Pectin Methylesterases Modulate Plant Homogalacturonan Status in Defenses against the Aphid .

Because they suck phloem sap and act as vectors for phytopathogenic viruses, aphids pose a threat to crop yields worldwide. Pectic homogalacturonan (HG) has been described as a defensive element for plants during infections with phytopathogens. However, its role during aphid infestation remains unexplored.

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.

The inside and outside: topological issues in plant cell wall biosynthesis and the roles of nucleotide sugar transporters.

The cell wall is a complex extracellular matrix composed primarily of polysaccharides. Noncellulosic polysaccharides, glycoproteins and proteoglycans are synthesized in the Golgi apparatus by glycosyltransferases (GTs), which use nucleotide sugars as donors to glycosylate nascent glycan and glycoprotein acceptors that are subsequently exported to the extracellular space. Many nucleotide sugars are synthesized in the cytosol, leading to a topological issue because the active sites of most GTs are located in the Golgi lumen.

The Golgi localized bifunctional UDP-rhamnose/UDP-galactose transporter family of Arabidopsis.

Plant cells are surrounded by a cell wall that plays a key role in plant growth, structural integrity, and defense. The cell wall is a complex and diverse structure that is mainly composed of polysaccharides. The majority of noncellulosic cell wall polysaccharides are produced in the Golgi apparatus from nucleotide sugars that are predominantly synthesized in the cytosol.

Local evolution of seed flotation in Arabidopsis.

Arabidopsis seeds rapidly release hydrophilic polysaccharides from the seed coat on imbibition. These form a heavy mucilage layer around the seed that makes it sink in water. Fourteen natural Arabidopsis variants from central Asia and Scandinavia were identified with seeds that have modified mucilage release and float.

Understanding polysaccharide production and properties using seed coat mutants: future perspectives for the exploitation of natural variants.

Background: The epidermal cells of the seed coat of certain species accumulate polysaccharides during seed development for cell wall reinforcement or release on imbibition to form mucilage. Seed-coat epidermal cells show natural variation in their structure and mucilage production, which could explain the diverse ecophysiological roles proposed for the latter. Arabidopsis mucilage mutants have proved to be an important tool for the identification of genes involved in the production of seed-coat polysaccharides.

PECTIN METHYLESTERASE INHIBITOR6 promotes Arabidopsis mucilage release by limiting methylesterification of homogalacturonan in seed coat epidermal cells.

Imbibed seeds of the Arabidopsis thaliana accession Djarly are affected in mucilage release from seed coat epidermal cells. The impaired locus was identified as a pectin methylesterase inhibitor gene, PECTIN METHYLESTERASE INHIBITOR6 (PMEI6), specifically expressed in seed coat epidermal cells at the time when mucilage polysaccharides are accumulated. This spatio-temporal regulation appears to be modulated by GLABRA2 and LEUNIG HOMOLOG/MUCILAGE MODIFIED1, as expression of PMEI6 is reduced in mutants of these transcription regulators.

Arabidopsis thaliana lipid phosphate phosphatase 2 is involved in abscisic acid signalling in leaves.

Lipid phosphate phosphatases (LPPs, E.C. 3.