Dataset Information

Phellem Cell-Wall Components Are Discriminants of Cork Quality in Quercus suber.

ABSTRACT: Cork is a renewable, non-wood high valued forest product, with relevant ecological and economic impact in the Mediterranean-type ecosystems. Currently, cork is ranked according to its commercial quality. The most valuable planks are chosen for cork stoppers production. Cork planks with adequate thickness and porosity are classified as stoppable quality cork (SQC). The chemical composition of cork is known, but the regulation of metabolic pathways responsible of cork production and composition, hence of cork quality, is largely unknown. Here, we tested the hypothesis that post-genomic events may be responsible for the development of SQC and N-SQC (non-stoppable quality cork). Here, we show that combined proteomics and targeted metabolomics (namely soluble and cell wall bound phenolics) analyzed on recently formed phellem allows discriminate cork planks of different quality. Phellem cells of SQC and N-SQC displayed different reducing capacity, with consequential impact on both enzymatic pathways (e.g., glycolysis) and other cellular functions, including cell wall assembly and suberization. Glycolysis and respiration related proteins were abundant in both cork quality groups, whereas the level of several proteins associated to mitochondrial metabolism was higher in N-SQC. The soluble and cell wall-bound phenolics in recently formed phellem clearly discriminated SQC from N-SCQ. In our study, SQC was characterized by a high incorporation of aromatic components of the phenylpropanoid pathway in the cell wall, together with a lower content of hydrolysable tannins. Here, we propose that the level of hydrolysable tannins may represent a valuable diagnostic tool for screening recently formed phellem, and used as a proxy for the quality grade of cork plank produced by each tree.

SUBMITTER: Pinheiro C

PROVIDER: S-EPMC6682605 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

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Publications

Phellem Cell-Wall Components Are Discriminants of Cork Quality in <i>Quercus suber</i>.

Pinheiro Carla C Wienkoop Stefanie S de Almeida João Feio JF Brunetti Cecilia C Zarrouk Olfa O Planchon Sébastien S Gori Antonella A Tattini Massimiliano M Ricardo Cândido Pinto CP Renaut Jenny J Teixeira Rita Teresa RT

Frontiers in plant science 20190730

Cork is a renewable, non-wood high valued forest product, with relevant ecological and economic impact in the Mediterranean-type ecosystems. Currently, cork is ranked according to its commercial quality. The most valuable planks are chosen for cork stoppers production. Cork planks with adequate thickness and porosity are classified as stoppable quality cork (SQC). The chemical composition of cork is known, but the regulation of metabolic pathways responsible of cork production and composition, h ...[more]

PMID: 31417580

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Project description:BACKGROUND: Cork oak (Quercus suber) is one of the rare trees with the ability to produce cork, a material widely used to make wine bottle stoppers, flooring and insulation materials, among many other uses. The molecular mechanisms of cork formation are still poorly understood, in great part due to the difficulty in studying a species with a long life-cycle and for which there is scarce molecular/genomic information. Cork oak forests are of great ecological importance and represent a major economic and social resource in Southern Europe and Northern Africa. However, global warming is threatening the cork oak forests by imposing thermal, hydric and many types of novel biotic stresses. Despite the economic and social value of the Q. suber species, few genomic resources have been developed, useful for biotechnological applications and improved forest management. RESULTS: We generated in excess of 7 million sequence reads, by pyrosequencing 21 normalized cDNA libraries derived from multiple Q. suber tissues and organs, developmental stages and physiological conditions. We deployed a stringent sequence processing and assembly pipeline that resulted in the identification of ~159,000 unigenes. These were annotated according to their similarity to known plant genes, to known Interpro domains, GO classes and E.C. numbers. The phylogenetic extent of this ESTs set was investigated, and we found that cork oak revealed a significant new gene space that is not covered by other model species or EST sequencing projects. The raw data, as well as the full annotated assembly, are now available to the community in a dedicated web portal at http://www.corkoakdb.org. CONCLUSIONS: This genomic resource represents the first trancriptome study in a cork producing species. It can be explored to develop new tools and approaches to understand stress responses and developmental processes in forest trees, as well as the molecular cascades underlying cork differentiation and disease response.

Project description:Purpose:Acetylcholinesterase (AChE) inhibitors are used to treat Alzheimer's patients because they enhance cholinergic neurotransmission. It is urgent to find new and efficient inhibitors from natural sources, highly bioavailable with low or no toxicity. The plant kingdom is extremely rich in a variety of compounds that are potent AChE inhibitors: flavonoids and other phenolic compounds have been recognized as promising Alzheimer's treatment agents. In this study, in vitro acetylcholinesterase inhibition, antioxidant activities, and total flavonoid and phenolic contents of ethanol-water extracts from Quercus suber cork and corkback were evaluated. Methods:The acetylcholinesterase activity was determined by a colorimetric assay based on Ellman's methodology. The Folin-Ciocalteu colorimetric method was used for total phenolic content determination and the aluminium chloride method for the determination of total flavonoid content. Antioxidant activity assays were performed using the DPPH and FRAP assays. Results:The acetylcholinesterase inhibitory activity from Q. suber cork and corkback ethanol-water extracts was as follows: 62% inhibition with corkback extracts over 0.5?mg/mL and around 49% inhibition in cork extracts over 1.0?mg/mL extracts' concentration. Regarding the DPPH radical scavenging activity, the concentrations of cork and corkback ethanol-water extracts required for 50% DPPH inhibition (IC50) were 3.2??g/mL and 4.0-5.2??g/mL. Corkback extracts are less effective than Trolox standard (3.2??g/mL) but cork extracts showed the same free radical scavenging activity compared to Trolox. Cork and corkback extracts have antioxidant power of 750.9-775.4?mg TEAC/g extract and 1051.2-2052.4?mg TEAC/g extract, respectively, which are significantly higher than the ones obtained with Trolox: 19.6-21.0?mg TEAC/g extract (cork assays) and 57.4-66.3?mg TEAC/g extract (corkback assays). The amounts of total phenolic (TPC) and flavonoid (TFC) compounds were 8.7-32.3?mg GAE/g and 4.8-10.7?mg CE/g dry mass for cork and 5.4-5.7?mg GAE/g and 42.5?mg CE/g dry mass for corkback extracts, respectively, using catechin (CE) and GAE (gallic acid) as standards. Conclusion:These findings demonstrate the remarkable potential of these extracts as valuable source of antioxidants with interesting acetylcholinesterase inhibitory activity.

Project description:Somatic embryogenesis is a reliable system for in vitro plant regeneration, with biotechnological applications in trees, but the regulating mechanisms are largely unknown. Changes in cell wall mechanics controlled by methylesterification of pectins, mediated by pectin methylesterases (PMEs) and pectin methyl esterase inhibitors (PMEIs) underlie many developmental processes. Arabinogalactan proteins (AGPs) are highly glycosylated proteins located at the surface of plasma membranes, in cell walls, and in extracellular secretions, with key roles in a range of different processes. In this study, we have investigated changes in two cell wall components, pectins and AGPs, during somatic embryogenesis in Quercus suber, a forest tree of high economic and ecologic value. At early embryogenesis stages, cells of proembryogenic masses showed high levels of esterified pectins and expression of QsPME and QsPMEI genes encoding a PME and a putative PMEI, respectively. At advanced stages, differentiating cells of heart, torpedo and cotyledonary embryos exhibited walls rich in de-esterified pectins, while QsPME gene expression and PME activity progressively increased. AGPs were detected in cell walls of proembryogenic masses and somatic embryos. QsLys-rich-AGP18, QsLys-rich-AGP17, and QsAGP16L1 gene expression increased with embryogenesis progression, as did the level of total AGPs, detected by dot blot with β-glucosyl Yariv reagent. Immuno dot blot, immunofluorescence assays and confocal analysis using monoclonal antibodies to high- (JIM7, LM20) and low- (JIM5, LM19) methylesterified pectins, and to certain AGP epitopes (LM6, LM2) showed changes in the amount and distribution pattern of esterified/de-esterified pectins and AGP epitopes, that were associated with proliferation and differentiation and correlated with expression of the PME and AGP genes analyzed. Pharmacological treatments with catechin, an inhibitor of PME activity, and Yariv reagent, which blocks AGPs, impaired the progression of embryogenesis, with pectin de-esterification and an increase in AGP levels being necessary for embryo development. Findings indicate a role for pectins and AGPs during somatic embryogenesis of cork oak, promoting the cell wall remodeling during the process. They also provide new insights into the regulating mechanisms of somatic embryogenesis in woody species, for which information is still scarce, opening up new possibilities to improve in vitro embryo production in tree breeding.

Dataset Information

Phellem Cell-Wall Components Are Discriminants of Cork Quality in Quercus suber.

Publications

Phellem Cell-Wall Components Are Discriminants of Cork Quality in <i>Quercus suber</i>.

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