Changes In Cell Wall Polymers Research Articles

Characterization of cell wall modification through thermogravimetric analysis during ripening of Chilean strawberry (Fragaria chiloensis) fruit

Fragaria chiloensis (Chilean strawberry) fruit has been described as a fruit with excellent organoleptic properties, highlighting its flavor and aroma. However, the fruit has a high softening rate. Fruit softening during the ripening process is a consequence of the solubilization and depolymerization of cell wall components. In the present work, we performed a comparative study of the changes in the physiological properties of the cell wall-associated polysaccharide contents of Chilean strawberry fruit via thermogravimetric analysis (TGA) combined with analyses of mRNA abundance, enzymatic activity, and physiological characteristics. The results showed that the thermal stability was lower in the ripe stage sample than in the other two samples, while the first derivative of the thermogram (DTG) curve described four maximum peaks of degradation, between 175 and 375 °C. The percentage cumulative depolymerization (PCD) was higher in the ripe samples, and the PCD value of 325° C, where 51.65% of the carbohydrate polymers present in the cell wall have been depolymerized, was highlighted. Finally, the existence of a relationship between the percentage of the cell wall polymer degradation and the solid soluble concentration (SSC)/firmness ratio, provides the basis for a model for understanding the changes in cell wall polymers during fruit development.

Abscisic acid applied to sweet cherry at fruit set increases amounts of cell wall and cuticular wax components at the ripe stage

Cuticle integrity represents an important factor in fruit quality of sweet cherries. Plants hormones, especially abscisic acid (ABA), are involved in fruit cuticle integrity. The effect of pre-harvest application of abscisic acid on cherry fruit cuticles was investigated. Changes of the concentrations of several phytohormones, expression levels of genes related to cell wall-modification, and to wax- and cutin biosynthesis were measured five days after applying ABA to sweet cherry trees (Prunus avium cv. Bing) at the stage of fruit set. At the ripe stage changes in cell wall polymers and fruit cuticle composition were measured. Our results show that pre-harvest application of 0.1 mM ABA at the stage of fruit set resulted in increased levels of zeatin ribose (204-fold), zeatin (126-fold), salicylic acid (30-fold), and ABA (19-fold). Transcription levels of key genes involved in cuticle biosynthesis, the transcription factor PaWINA and the wax biosynthesis-related enzyme PaLACS1 (5.8- and 3.4-fold increase), as well as for the key enzyme PaNCED1, involved in ABA biosynthesis (6.9-fold increase), were increased. At the ripe stage, contents of covalently-bound pectins and hemicelluloses were higher with a concomitant reduction of water-soluble polymers in ABA-treated fruits. Amounts of linear long-chain aliphatic wax compounds, especially C27, C29, and C31 alkanes, were increased (1.2-, 1.3- and 2.3-fold, respectively), whereas no effect of ABA on pentycylcic triterpenoids was observed. We conclude that ABA treatment of cherry trees at the stage of fruit set positively affects sweet cherry fruit quality at ripening by enforcing the cell wall and modifying the cuticle composition.

Molecular Events Occurring During Softening of Strawberry Fruit.

Changes in fruit texture taking place during ripening, described as softening, are mainly due to alterations in structure and/or composition of the cell wall. Several non-covalent interactions between the three carbohydrate polymers of the cell wall, cellulose, pectins and hemicellulose, and many structural proteins and ions, enable a complex structure. During softening, the disassembly of the cell wall structure takes place, mediated by a complete set of cell wall degrading enzymes or proteins. Softening is a coordinated event that requires the orchestrated participation of a wide variety of proteins. Plant hormones and a set of transcription factors are the organizers of this multi-protein effort. Strawberry is a non climacteric fruit that softens intensively during the last stages of development. The Chilean strawberry fruit (Fragaria chiloensis), the maternal relative of the commercial strawberry (F. × ananassa), softens even faster than commercial strawberry. Softening of the Chilean strawberry fruit has been studied at different levels: changes in cell wall polymers, activity of cell wall degrading enzymes and transcriptional changes of their genes, providing a general view of the complex process. The search for the ‘orchestra director’ that could coordinate softening events in strawberry fruit has been focussed on hormones like ABA and auxins, and more precisely the relation ABA/AUX. These hormones regulate the expression of many cell wall degrading enzyme genes, and this massive transcriptional change that takes place involves the participation of key transcriptional factors (TF). This review provides an update of the present knowledge regarding the softening of strawberry fruit. Nevertheless, the entire softening process is still under active research especially for the great influence of texture on fruit quality and its high impact on fruit shelf life, and therefore it is expected that new and promising information will illuminate the field in the near future.

High-throughput microarray mapping of cell wall polymers in roots and tubers during the viscosity-reducing process.

Viscosity reduction has a great impact on the efficiency of ethanol production when using roots and tubers as feedstock. Plant cell wall-degrading enzymes have been successfully applied to overcome the challenges posed by high viscosity. However, the changes in cell wall polymers during the viscosity-reducing process are poorly characterized. Comprehensive microarray polymer profiling, which is a high-throughput microarray, was used for the first time to map changes in the cell wall polymers of sweet potato (Ipomoea batatas), cassava (Manihot esculenta), and Canna edulis Ker. over the entire viscosity-reducing process. The results indicated that the composition of cell wall polymers among these three roots and tubers was markedly different. The gel-like matrix and glycoprotein network in the C. edulis Ker. cell wall caused difficulty in viscosity reduction. The obvious viscosity reduction of the sweet potato and the cassava was attributed to the degradation of homogalacturonan and the released 1,4-β-d-galactan and 1,5-α-l-arabinan.

Cotton fiber: a powerful single-cell model for cell wall and cellulose research.

Cotton fibers are single-celled extensions of the seed epidermis. They can be isolated in pure form as they undergo staged differentiation including primary cell wall synthesis during elongation and nearly pure cellulose synthesis during secondary wall thickening. This combination of features supports clear interpretation of data about cell walls and cellulose synthesis in the context of high throughput modern experimental technologies. Prior contributions of cotton fiber to building fundamental knowledge about cell walls will be summarized and the dynamic changes in cell wall polymers throughout cotton fiber differentiation will be described. Recent successes in using stable cotton transformation to alter cotton fiber cell wall properties as well as cotton fiber quality will be discussed. Futurec prospects to perform experiments more rapidly through altering cotton fiberwall properties via virus-induced gene silencing will be evaluated.

The Plant Cell Wall: A Dynamic Barrier Against Pathogen Invasion

Prospective plant pathogens must overcome the physical barrier presented by the plant cell wall. In addition to being a preformed, passive barrier limiting access of pathogens to plant cells, the cell wall is actively remodeled and reinforced specifically at discrete sites of interaction with potentially pathogenic microbes. Active reinforcement of the cell wall through the deposition of cell wall appositions, referred to as papillae, is an early response to perception of numerous categories of pathogens including fungi and bacteria. Rapid deposition of papillae is generally correlated with resistance to fungal pathogens that attempt to penetrate plant cell walls for the establishment of feeding structures. Despite the ubiquity and apparent importance of this early defense response, relatively little is known about the underlying molecular mechanisms and cellular processes involved in the targeting and assembly of papillae. This review summarizes recent advances in our understanding of cell wall-associated defenses induced by pathogen perception as well as the impact of changes in cell wall polymers on interactions with pathogens and highlights significant unanswered questions driving future research in the area.

Cell wall components and pectin esterification levels as markers of proliferation and differentiation events during pollen development and pollen embryogenesis in Capsicum annuum L.

Plant cell walls and their polymers are regulated during plant development, but the specific roles of their molecular components are still unclear, as well as the functional meaning of wall changes in different cell types and processes. In this work the in situ analysis of the distribution of different cell wall components was performed during two developmental programmes, gametophytic pollen development, which is a differentiation process, and stress-induced pollen embryogenesis, which involves proliferation followed by differentiation processes. The changes in cell wall polymers were compared with a system of plant cell proliferation and differentiation, the root apical meristem. The analysis was also carried out during the first stages of zygotic embryogenesis. Specific antibodies recognizing the major cell wall polymers, xyloglucan (XG) and the rhamnogalacturonan II (RGII) pectin domain, and antibodies against high- and low-methyl-esterified pectins were used for both dot-blot and immunolocalization with light and electron microscopy. The results showed differences in the distribution pattern of these molecular complexes, as well as in the proportion of esterified and non-esterified pectins in the two pollen developmental pathways. Highly esterified pectins were characteristics of proliferation, whereas high levels of the non-esterified pectins, XG and RGII were abundant in walls of differentiating cells. Distribution patterns similar to those of pollen embryos were found in zygotic embryos. The wall changes reported are characteristic of proliferation and differentiation events as markers of these processes that take place during pollen development and embryogenesis.

A rapid way of tracking changes in cell wall polymers during biofuel production

Biotechnology and BioengineeringVolume 105, Issue 3 p. fmv-fmv Spotlight A rapid way of tracking changes in cell wall polymers during biofuel production First published: 23 December 2009 https://doi.org/10.1002/bit.22624AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume105, Issue315 February 2010Pages fmv-fmv RelatedInformation

Immunocytological Analysis of Potato Tuber Periderm and Changes in Pectin and Extensin Epitopes Associated with Periderm Maturation

Potato (Solanum tuberosum L.) periderm forms a barrier at the surface of the tuber that protects it from infection and dehydration. Immature periderm is susceptible to excoriation (skinning injury), which results in costly storage loses and market quality defects. The periderm consists of three different cell types: phellem (skin), phellogen (cork cambium), and phelloderm (parenchyma-like cells). The phellogen serves as a lateral meristem for the periderm and is characterized by thin radial walls that are labile to fracture while the periderm is immature and the phellogen is actively dividing, thus rendering the tuber susceptible to excoriation. As the periderm matures the phellogen becomes inactive, its cell walls thicken and become resistant to fracture, and thus the tuber becomes resistant to excoriation. Little is known about the changes in cell wall polymers that are associated with tuber periderm maturation and the concurrent development of resistance to excoriation. Various changes in pectins (galacturonans and rhamnogalacturonans) and extensin may be involved in this maturational process. The objectives of this research were to compare immunolabeling of homogalacturonan (HG) epitopes to labeling of rhamnogalacturonan I (RG-I) and extensin epitopes to better understand the depositional patterns of these polymers in periderm cell walls and their involvement in tuber periderm maturation. Immunolabeling with the monoclonal antibodies JIM5 and JIM7 (recognizing a broad range of esterified HG) confirmed that HG epitopes are lacking in phellogen walls of immature periderm, but increased greatly upon maturation of the periderm. Labeling of a (1,4)-β-galactan epitope found in RG-I and recognized by the monoclonal antibody LM5 was abundant in phelloderm cell walls, but sparse in most phellem cell walls. LM5 labeling was very sparse in the walls of meristematically active phellogen cells of immature periderm, but increased dramatically upon periderm maturation. Deposition of a (1,5)-α-l-arabinan epitope found in RG-I and recognized by LM6 was abundant in phelloderm and phellogen cell walls, but was sparse in phellem cell walls. LM6 labeling of phellogen walls did not change upon periderm maturation, indicating that different RG-1 epitopes are regulated independently during maturation of the periderm. Labeling with the monoclonal antibody LM1 for an extensin epitope implied that extensin is lacking in phellem cell walls, but is abundant in phelloderm cell walls. Phellogen cell walls did not label with LM1 in immature periderm, but were abundantly labeled with LM1 in mature periderm. These immunolabeling studies identify pectin and extensin depositions as likely biochemical processes involved in the thickening and related strengthening of phellogen walls upon inactivation of the phellogen layer as a lateral meristem and maturation of the periderm in potato tuber. These results provide unique and new insight into the identities of some of the biological processes that may be targeted in the development of new technologies to enhance resistance to tuber skinning injury for improved harvest, handling and storage properties.

Modification of cell-wall polymers of onion waste—Part I. Effect of pressure-cooking

The extraction of polymers from onion cell walls and the mechanical properties of onion tissues can be modified by heating. However, there is little information on the effects of thermal treatments on the chemistry of cell-wall polysaccharides of onion tissues. The present work reports pressure-cooking-induced changes in cell-wall polymers of onion waste. The outer fleshy scale leaves of onion ( Allium cepa L. cv. Delta and Hysam) were subjected to a range of pressure-cooking times (0, 10, 20, 30 and 50 min, 120°C). Cell-wall material was prepared as cold-alcohol-insoluble residues and subsequently extracted with buffered phenol. The cell-wall material was then extracted sequentially with water, NaCl, imidazole, cyclohexane- trans-1,2-diaminetetraacetate (CDTA), Na 2CO 3 and KOH to leave a residue. The samples were analysed for their carbohydrate composition, their degree of methylesterification and the molecular size of selected soluble polysaccharides. Pressure-cooking-induced softening of onion tissue involved cell-wall swelling and cell separation. This was accompanied by an increase in water-soluble pectic polysaccharides and a decrease in the pectic polymers of the imidazole, CDTA, Na 2CO 3 and KOH-soluble fractions and insoluble residue. Pressure-cooking also resulted in a slight decrease in the peak molecular weight of water-soluble polysaccharides.

Developmental and ripening-related effects on the cell wall of apricot (Prunus armeniaca) fruit

Alcohol-insoluble residues (AIRs) were prepared from apricots at six stages during development/ripening on the tree. To investigate the changes in cell wall polymers, and in particular those affecting pectic polysaccharides, the AIR preparations were sequentially extracted with water, cyclohexane-trans-1,2-diamine-N,N,N′,N′-tetraacetate (CDTA) and Na2CO3. A significant proportion of initially Na2CO3-soluble pectic polysaccharides became water- and CDTA-soluble during the ripening process. In terms of composition, a significant decrease in galactose and uronic acid content was detected in all the extractions, whereas the percentage of arabinose increased in both water and CDTA-soluble polymers but decreased in the Na2CO3-extracted polysaccharides. The ability of pectic polysaccharides to cross-link was diminished during ripening due to an overall increase in the concentration of Na+ or K+ associated with the AIRs. This was accompanied by a decrease in the amounts of Ca2+ and Mg2+. The decrease in pectic galactans and the inhibition of pectin cross-linking detected within the pectic backbone are probably linked to the softening process observed during apricot ripening. © 1998 SCI.

Developmental and ripening‐related effects on the cell wall of apricot (Prunus armeniaca) fruit

Alcohol-insoluble residues (AIRs) were prepared from apricots at six stages during development/ripening on the tree. To investigate the changes in cell wall polymers, and in particular those affecting pectic polysaccharides, the AIR preparations were sequentially extracted with water, cyclohexane-trans-1,2-diamine-N,N,N′,N′-tetraacetate (CDTA) and Na2CO3. A significant proportion of initially Na2CO3-soluble pectic polysaccharides became water- and CDTA-soluble during the ripening process. In terms of composition, a significant decrease in galactose and uronic acid content was detected in all the extractions, whereas the percentage of arabinose increased in both water and CDTA-soluble polymers but decreased in the Na2CO3-extracted polysaccharides. The ability of pectic polysaccharides to cross-link was diminished during ripening due to an overall increase in the concentration of Na+ or K+ associated with the AIRs. This was accompanied by a decrease in the amounts of Ca2+ and Mg2+. The decrease in pectic galactans and the inhibition of pectin cross-linking detected within the pectic backbone are probably linked to the softening process observed during apricot ripening. © 1998 SCI.

Compositional changes in cell wall polymers during mango fruit ripening

Softening of mango fruit has been investigated by analysis of ripening related changes in the composition of the fruit cell walls. There is an apparent overall loss of galactosyl and deoxyhexosyl residues during ripening, the latter indicating degradation of the pectin component of the wall. The loss of galactose appears to be restricted to the chelator soluble fraction of the wall pectin, whilst loss of deoxyhexose seems to be more evenly distributed amongst the pectin. The chelator soluble pectin fraction is progressively depolymerised and becomes more polydisperse during ripening. These changes are similar to those occurring in other fruit and are related to the action of wall hydrolases during ripening.

Cell Wall Changes in Spanish Pear During Ripening

Summary Unripe Spanish pears ( Pyrus communis , c.v. Blanquille) were allowed to ripen at 18°C for 1 week. Cell walls were prepared as alcohol-insoluble residues (AIRS) which were free of starch. On a fresh weight basis, ripening was accompanied by a decrease in cell wall arabinose and uronic acid, a proportion of which were metabolised, and an increase in xylose and glucose. To investigate the origin of the changes in cell wall polymers, the AIRS of unripe and ripe fruit were extracted sequentially with water, cyclohexane trans -1,2-diamine- N, N, N', N' -tetraacetate (CDTA), Na 2 CO 3 at 1°C and 20°C, 0.5, 1 and 4M KOH to leave a cellulose-rich residue. The extracts and residues were analysed for their carbohydrate composition and, where appropriate, degree of pectin-methyl esterification. The water, CDTA and Na2C03 extracted polymers were rich in pectic polysaccharides. These exhibited heterogeneity in the ratios of neutral and acidic components and contained small quantities of xylose. The KOH-extracted polymers were rich in hemicelluloses, particularly xylans, but also contained sugars common to pectic polysaccharides. The cellulose-rich residues were rich in cellulosic glucose and xylose which probably originated from the highlylignified sclereids. Ripening resulted in an increase in water- and CDTA-soluble pectic polysaccharides which exhibited a lower degree of pectin-methyl esterification. These results and the changes in carbohydrate composition are discussed in the light of corresponding decreases in the yields of pectic polysaccharides of the Na 2 CO 3 extracts and cellulose-rich residues during ripening.

HEMICELLULOSE APPARENT MOLECULAR SIZE CHANGES DURING SOFTENING OF PEACH FRUIT

Peach fruit softening appears to be associated with changes in cell wall polymers, particularly pectins and hemicelluloses. To determine changes of cell wall polymers associated with peach fruit softening, we conducted sequential extractions of pectin and hemicellulose from softening fruit. A more tightly bound hemicellulose fraction contained considerable amounts of pectin associated sugars. This fraction was separated into charged and neutral fractions, using anion exchange chromatography, and then fractionated into two apparent molecular weight classes by size exclusion chromatography. Virtually all of the charged fraction eluted in the higher apparent molecular weight fraction. The neutral sugar fraction segregated into both apparent molecular weight size classes, with a redistribution from the large to the small size class during softening. This redistribution was accompanied by changes in neutral sugar composition. A possible relationship between changes in this fraction and fruit softening will be discussed. Supported by USDA grant 92-34150-7190 and the Oklahoma Agricultural Experiment Station.