Dietary fiber(DF)is one of the major classes of nutrients for humans.It is widely distributed in the edible parts of natural plants,with the cell wall being the main DF-containing structure.DF content varies significa...Dietary fiber(DF)is one of the major classes of nutrients for humans.It is widely distributed in the edible parts of natural plants,with the cell wall being the main DF-containing structure.DF content varies significantly in different plant species and organs,and the processing procedure can have a dramatic effect on the DF composition of plant-based foods.Given the considerable nutritional value of DF,a deeper understanding of DF in food plants,including its composition and biosynthesis,is fundamental to the establishment of a daily intake reference of DF and is also critical to molecular breeding programs for modifying DF content.In the past decades,plant cell wall biology has seen dramatic progress,and such knowledge is of great potential to be translated into DF-related food science research and may provide future research directions for improving the health benefits of food crops.In this review,to spark interdisciplinary discussions between food science researchers and plant cell wall biologists,we focus on a specific category of DF--cell wall carbohydrates.We first summarize the content and composition of carbohydrate DF in various plant-based foods,and then discuss the structure and biosynthesis mechanism of each carbohydrate DF category,in particular the respective biosynthetic enzymes.Health impacts of DF are highlighted,and finally,future directions of DF research are also briefly outlined.展开更多
The plant cell wall is a complex 3D network composed of polysaccharides, lignin and proteins. The knowledge of the structure and content of each cell wall polymer is a prerequisite to understand their functions during...The plant cell wall is a complex 3D network composed of polysaccharides, lignin and proteins. The knowledge of the structure and content of each cell wall polymer is a prerequisite to understand their functions during plant development and adaptation but also to optimise their industrial applications. The analysis of cell wall compounds is complicated by their multiple molecular interactions. In this review, we present numerous methods to purify, characterise and quantify proteins, polysaccharides and lignin from the wall. Two kinds of approaches are detailed: the first presents in vitro methods which involve the breakdown of the molecular linkages between polymers thanking to chemical, physical and/or enzymatic treatments. The second approach describes in situ methods that allow the cell wall polymer characterisation thanking to many analytical techniques coupled with microscopy. If microscopy is the common point of all of them, their development is associated with improvement of analytical techniques, increasing their power of resolution.展开更多
Resurrection fern has a unique ability to maintain cell wall integrity when the plant cell is desiccated. It uses proteins such as late embryogenesis proteins and heat shock proteins to maintain their cellular functio...Resurrection fern has a unique ability to maintain cell wall integrity when the plant cell is desiccated. It uses proteins such as late embryogenesis proteins and heat shock proteins to maintain their cellular functions. The purpose of this experiment is to determine the effects of environmental stressors on the physiological response of the resurrection fern (Pleopeltis polypodioides). The physiological response of resurrection fern plants was subjected to various temperatures (-50°C, 0°C, 25°C, and 50°C) for 7 days. Results indicated that there was a significant difference between hydrated and desiccated ferns based on the temperature. Additionally, electrolyte leakage measurements confirmed cell damage following exposure to temperature extremes of -50°C and 50°C.展开更多
All plant cells are surrounded by a cell wall that provides cohesion,protection,and a means of directional growth to plants.Cellulose microfibrils contribute the main biomechanical scaffold for most of these walls.The...All plant cells are surrounded by a cell wall that provides cohesion,protection,and a means of directional growth to plants.Cellulose microfibrils contribute the main biomechanical scaffold for most of these walls.The biosynthesis of cellulose,which typically is the most prominent constituent of the cell wall and therefore Earth’s most abundant biopolymer,is finely attuned to developmental and environmental cues.Our understanding of the machinery that catalyzes and regulates cellulose biosynthesis has substantially improved due to recent technological advances in,for example,structural biology and microscopy.Here,we provide a comprehensive overview of the structure,function,and regulation of the cellulose synthesis machinery and its regulatory interactors.We aim to highlight important knowledge gaps in the field,and outline emerging approaches that promise a means to close those gaps.展开更多
Fruit softening in tomato(Solanum lycopersicum)is closely associated with cell wall disassembly,which is brought about through the action of a range of cell wall structure-related enzymes and other proteins such as ex...Fruit softening in tomato(Solanum lycopersicum)is closely associated with cell wall disassembly,which is brought about through the action of a range of cell wall structure-related enzymes and other proteins such as expansins.Xyloglucan endotransglucosylase/hydrolase(XTH)(EC 2.4.1.207 and/or EC 3.2.1.151)has been proposed to be key player involved in xyloglucan metabolism.SlXTH5 showed the highest expression level among all SlXTHs during tomato ripening.In this study,the role of SlXTH5 involved in tomato softening was investigated in CRISPR-based knockout mutants of SlXTH5.Loss-of-function of SlXTH5 in transgenic tomato lines resulted in slightly firmer fruit pericarp,but significantly decreased their color index compared with azygous wild type(WT)control fruits.Increased paste viscosity was detected in CRISPR mutants,indicating that the activity of SlXTH5 is responsible for maintaining cell wall structural integrity.Immunocytochemistry studies were performed using the monoclonal antibody probe LM25 to examine the localization and distribution of xyloglucan in the pericarp cells of the CRISPR mutant fruits.The data indicated more xyloglucan was retained in the pericarp of CRISPR mutant fruit than in WT control fruit.This study revealed the link between SlXTH5 and xyloglucan metabolism and indicated the potential of manipulating SlXTH5 to regulate fruit softening.展开更多
Plant cell walls contain elaborate polysaccharide networks and regulate plant growth, development, mechanics, cell-cell communication and adhesion, and defense. Despite conferring rigidity to support plant structures,...Plant cell walls contain elaborate polysaccharide networks and regulate plant growth, development, mechanics, cell-cell communication and adhesion, and defense. Despite conferring rigidity to support plant structures, the cell wall is a dynamic extracellular matrix that is modified, reorganized, and degraded to tightly control its properties during growth and development. Far from being a terminal carbon sink, many wall polymers can be degraded and recycled by plant cells, either via direct re-incorporation by trans- glycosylation or via internalization and metabolic salvage of wall-derived sugars to produce new precur- sors for wall synthesis. However, the physiological and metabolic contributions of wall recycling to plant growth and development are largely undefined. In this review, we discuss long-standing and recent evi- dence supporting the occurrence of cell-wall recycling in plants, make predictions regarding the develop- mental processes to which wall recycling might contribute, and identify outstanding questions and emerging experimental tools that might be used to address these questions and enhance our understanding of this poorly characterized aspect of wall dynamics and metabolism.展开更多
Among the potential non-food energy crops,the sugar-rich C4 grass sweet sorghum and the biomass-rich Miscanthus are increasingly considered as two leading candidates.Here,we outline the biological traits of these ener...Among the potential non-food energy crops,the sugar-rich C4 grass sweet sorghum and the biomass-rich Miscanthus are increasingly considered as two leading candidates.Here,we outline the biological traits of these energy crops for largescale production in China.We also review recent progress on understanding of plant cell wall composition and wall polymer features of both plant species from large populations that affect both biomass enzymatic digestibility and ethanol conversion rates under various pretreatment conditions.We finally propose genetic approaches to enhance biomass production,enzymatic digestibility and sugar-ethanol conversion efficiency of the energy crops.展开更多
Root hairs and pollen tubes are formed through tip growth, a process requiring synthesis of new cell wall material and the precise targeting and integration of these components to a selected apical plasma membrane dom...Root hairs and pollen tubes are formed through tip growth, a process requiring synthesis of new cell wall material and the precise targeting and integration of these components to a selected apical plasma membrane domain in the growing tips of these cells. Presence of a tip-focused calcium gradient, control of actin cytoskeleton dynamics, and formation and targeting of secretory vesicles are essential to tip growth. Similar to cells undergoing diffuse growth, cellulose, hemi-celluloses, and pectins are also deposited in the growing apices of tip-growing cells. However, differences in the manner in which these cell wall components are targeted and inserted in the expanding portion of tip-growing cells is reflected by the identification of elements of the plant cell wall synthesis machinery which have been shown to play unique roles in tip-growing cells. In this review, we summarize our current understanding of the tip growth process, with a particular focus on the subcellular targeting of newly synthesized cell wall components, and their roles in this form of plant cell expansion.展开更多
Virus-induced gene silencing (VIGS) is a powerful genetic tool for rapid assessment of plant gene functions in the post-genomic era. Here, we successfully implemented a Tobacco Rattle Virus (TRV)-based VlGS system...Virus-induced gene silencing (VIGS) is a powerful genetic tool for rapid assessment of plant gene functions in the post-genomic era. Here, we successfully implemented a Tobacco Rattle Virus (TRV)-based VlGS system to study functions of genes involved in either primary or secondary cell wall formation in Nicotiana benthamiana plants. A 3-week post- VIGS time frame is sufficient to observe phenotypic alterations in the anatomical structure of stems and chemical composition of the primary and secondary cell walls. We used cell wall glycan-directed monoclonal antibodies to demonstrate that alteration of cell wall polymer synthesis during the secondary growth phase of VIGS plants has profound effects on the extractability of components from woody stem cell walls. Therefore, TRV-based VlGS together with cell wall component profiling methods provide a high-throughput gene discovery platform for studying plant cell wall formation from a bioenergy perspective.展开更多
Transglycanases(endotransglycosylases) cleave a polysaccharide(donor-substrate) in mid-chain, and then transfer a portion onto another poly-or oligosaccharide(acceptor-substrate). Such enzymes contribute to plan...Transglycanases(endotransglycosylases) cleave a polysaccharide(donor-substrate) in mid-chain, and then transfer a portion onto another poly-or oligosaccharide(acceptor-substrate). Such enzymes contribute to plant cellwall assembly and/or re-structuring. We sought a general method for revealing novel homo- and hetero-transglycanases, applicable to diverse polysaccharides and oligosaccharides, separating transglycanase-generated3 Hpolysaccharides from unreacted3H-oligosaccharides—the former immobilized(on filter-paper, silica-gel or glassfiber),the latter eluted. On filter-paper, certain polysaccharides [e.g.(1!3, 1!4)-b-D-glucans] remained satisfactorily adsorbed when water-washed; others(e.g. pectins) were partially lost. Many oligosaccharides(e.g. arabinan-, galactan-, xyloglucan-based) were successfully eluted in appropriate solvents, but others(e.g. [3H]xylohexaitol, [3H]mannohexaitol[3H]cellohexaitol) remained immobile. On silica-gel, all3 Holigosaccharides left an immobile ‘ghost’ spot(contaminating any3H-polysaccharides), which was diminished but not prevented by additives e.g. sucrose or Triton X-100. The best stratum was glassfiber(GF), onto which the reactionmixture was dried then washed in 75% ethanol. Washing led to minimal loss or lateral migration of3H-polysaccharides if conducted by slow percolation of acidified ethanol. The effectiveness of GF-blotting was well demonstrated for Chara vulgaris transb-mannanase. In conclusion, our novel GF-blotting technique ef ficiently frees transglycanase-generated3H-polysaccharides from unreacted3H-oligosaccharides,enabling high-throughput screening of multiple postulated transglycanase activities utilising chemically diverse donorand acceptor-substrates.展开更多
The triennial International Conference on Plant Cell Wall Biology has been held 5 times since it was initiated in the United States. PCWB2017 for the first time is organized in China. The conference was attended with ...The triennial International Conference on Plant Cell Wall Biology has been held 5 times since it was initiated in the United States. PCWB2017 for the first time is organized in China. The conference was attended with more than 220 participants and featured with oral and poster presentations, reflecting the contemporarv status of plant cell wall studies.展开更多
Xyloglucans in the non-lignified primary cell walls of different species of monocotyledons have diverse struc- tures, with widely varying proportions of oligosaccharide units that contain fucosylated side chains (F s...Xyloglucans in the non-lignified primary cell walls of different species of monocotyledons have diverse struc- tures, with widely varying proportions of oligosaccharide units that contain fucosylated side chains (F side chains). To determine whether fucosylated xyloglucans occur in all non-lignified walls in a range of monocotyledon species, we used immunofluorescence microscopy with the monoclonal antibody CCRC-M1. The epitope of this antibody, α-L-FUCp-(1 →2)- β-D-Galp, occurs in F side chains. In most non-commelinid monocotyledons, the epitope was found in all non-lignified walls. A similar distribution was found in the palm Phoenix canariensis, which is a member of the basal commelinid order Arecales. However, in the other commelinid orders Zingiberales, Commelinales, and Poales, the occurrence of the epitope was restricted, sometimes occurring in only the phloem walls, but often also in walls of other cell types including stomatal guard and subsidiary cells and raphide idioblasts. No epitope was found in the walls of the commelinids Tradescantia virginiana (Commelinaceae, Commelinales) and Zea mays (Poaceae, Poales), but it occurred in the phloem walls of two other Poaceae species, Lolium multiflorum and L. perenne. The distribution of the epitope is discussed in relation to xyloglucan structures in the different taxa. However, the functional significance of the restricted distributions is unknown.展开更多
Research on the many aspects of the plant cell wall has experienced reiuvenation during the past few years. This is perhaps mainly due to the commercial interest in the chemical components of the cell wall that have p...Research on the many aspects of the plant cell wall has experienced reiuvenation during the past few years. This is perhaps mainly due to the commercial interest in the chemical components of the cell wall that have potential for industrial use" Cellulose for fibers and together with hemicelluloses for bioethanol, lignin for plastics or biofuel, pectins as gel agents, let alone woody cell wall material for construction or pulp production and for intelligent materials for electronics - the new uses are mindboggling!展开更多
The wood polysaccharide composition, a new analytical method, based on ionic liquid dissolution of low amount of biomass coupled with an ELISA essay of polysaccharides. In the present work, we synthesized and tested s...The wood polysaccharide composition, a new analytical method, based on ionic liquid dissolution of low amount of biomass coupled with an ELISA essay of polysaccharides. In the present work, we synthesized and tested several imidazolium and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) based ILs for their ability to solubilize Douglas-fir wood while preserving the wall polymer integrity. The couple times-temperatures have been essayed for wood dissolution. Then their efficiency for wood biomass dissolution was compared to the impact of IL on storing and/or destroy polysaccharides. Thanks to the ELISA technique with a set of mAbs against epitopes of the main hemicellulose, pectin, and protein families of cell wall components. Wood destructuration at 80˚C with the 1-ethyl-3-methylimidazolium bromide represents a good compromise of wood dissolution efficiency and low polysaccharide destruction.展开更多
The cell wall provides external support of the plant cells, while the cytoskeletons including the microtubules and the actin filaments constitute an internal framework. The cytoskeletons contribute to the cell wall bi...The cell wall provides external support of the plant cells, while the cytoskeletons including the microtubules and the actin filaments constitute an internal framework. The cytoskeletons contribute to the cell wall biosynthesis by spatially and temporarily regulating the transportation and deposition of cell wall components. This tight control is achieved by the dynamic behavior of the cytoskeletons, but also through the tethering of these structures to the plasma membrane. This tethering may also extend beyond the plasma membrane and impact on the cell wall, possibly in the form of a feedback loop. In this review, we discuss the linking components between the cytoskeletons and the plasma membrane, and/or the cell wall. We also discuss the prospective roles of these components in cell wall biosyn- thesis and modifications, and aim to provide a platform for further studies in this field.展开更多
Glucose (Glu) is involved in not only plant physiological and developmental events but also plant responses to abiotic stresses. Here, we found that the exogenous Glu improved root and shoot growth, reduced shoot cadm...Glucose (Glu) is involved in not only plant physiological and developmental events but also plant responses to abiotic stresses. Here, we found that the exogenous Glu improved root and shoot growth, reduced shoot cadmium (Cd) concentration, and rescued Cd-induced chlorosis in Arabidopsis thaliana (Columbia ecotype, Col-0) under Cd stressed conditions. Glucose increased Cd retained in the roots, thus reducing its translocation from root to shoot significantly. The most Cd retained in the roots was found in the hemicellulose 1. Glucose combined with Cd (Glu t Cd) treatment did not affect the content of pectin and its binding capacity of Cd while it increased the content of hemicelluloses 1 and the amount of Cd retained in it significantly. Furthermore, Leadmium Green staining indicated that more Cd was compartmented into vacuoles in Glu t Cd treatment compared with Cd treatment alone, which was in accordance with the significant upregulation of the expression of tonoplast-localized metal transporter genes, suggesting that com-partmentation of Cd into vacuoles also contributes to the Glu-alleviated Cd toxicity. Taken together, we demonstrated that Glu-alleviated Cd toxicity is mediated through increas-ing Cd fixation in the root cell wall and sequestration into the vacuoles.展开更多
The CELLULOSE SYNTHASE-LIKE C (CSLC) family is an ancient lineage within the CELLULOSE SYNTHASE/CELLULOSE SYNTHASE-LIKE (CESA/CSL) polysaccharide synthase superfamily that is thought to have arisen before the dive...The CELLULOSE SYNTHASE-LIKE C (CSLC) family is an ancient lineage within the CELLULOSE SYNTHASE/CELLULOSE SYNTHASE-LIKE (CESA/CSL) polysaccharide synthase superfamily that is thought to have arisen before the divergence of mosses and vascular plants. As studies in the flowering plant Arabidopsis have suggested synthesis of the (1,4)-β-glucan backbone of xyloglucan (XyG), a wall polysaccharide that tethers adjacent cellulose microfibrils to each other, as a probable function for the CSLCs, CSLC function was investigated in barley (Hordeum vulgate L.), a species with low amounts of XyG in its walls. Four barley CSLCgenes were identified (designated HvCSLC1-4). Phylogenetic analysis reveals three well supported clades of CSLCs in flowering plants, with barley having representatives in two of these clades. The four barley CSLCs were expressed in various tissues, with in situ PCR detecting transcripts in all cell types of the coleoptile and root, including cells with primary and secondary cell walls. Co-expression analysis showed that HvCSLC3 was coordinately expressed with putative XyG xylosyltransferase genes. Both immuno-EM and membrane fractionation showed that HvCSLC2 was located in the plasma membrane of barley suspension-cultured cells and was not in internal membranes such as endoplasmic reticulum or Golgi apparatus. Based on our current knowledge of the sub-cellular locations of polysaccharide synthesis, we conclude that the CSLC family probably contains more than one type of polysaccharide synthase.展开更多
Maintenance of cell wall integrity is of great importance not only for plant growth and development,but also for the adaptation of plants to adverse environments.However,how the cell wall integrity is modulated under ...Maintenance of cell wall integrity is of great importance not only for plant growth and development,but also for the adaptation of plants to adverse environments.However,how the cell wall integrity is modulated under salt stress is still poorly understood.Here,we report that a nuclear-localized Agenet domain-containing protein SWO1(SWOLLEN 1)is required for the maintenance of cell wall integrity in Arabidopsis under salt stress.Mutation in SWO1 gene results in swollen root tips,disordered root cell morphology,and root elongation inhibition under salt stress.The swo1 mutant accumulates less cellulose and pectin but more lignin under high salinity.RNA-seq and ChIP-seq assays reveal that SWO1 binds to the promoter of several cell wall-related genes and regulates their expression under saline conditions.Further study indicates that SWO1 interacts with importinɑIMPA1 and IMPA2,which are required for the import of nuclear-localized proteins.The impa1 impa2 double mutant also exhibits root growth inhibition under salt stress and mutations of these two genes aggravate the salt-hypersensitive phenotype of the swo1 mutant.Taken together,our data suggest that SWO1 functions together with importinɑto regulate the expression of cell wall-related genes,which enables plants to maintain cell wall integrity under high salinity.展开更多
Maintenance of root elongation is beneficial for the growth and survival of plants under salt stress,but currently the cellular components involved in the regulation of root growth under high salinity are not fully un...Maintenance of root elongation is beneficial for the growth and survival of plants under salt stress,but currently the cellular components involved in the regulation of root growth under high salinity are not fully understood.In this study,we identified an Arabidopsis mutant,rres1,which exhibited reduced root elongation under treatment of a variety of salts,including NaCl,NaNO3,KCl,and KNO3.RRES1 encodes a novel mitochondrial protein and its molecular function is still unknown.Under salt stress,the root meristem length was shorter in the rres1 mutant compared to the wild type,which was correlated with a reduced auxin accumulation in the mutant.Reactive oxygen species(ROS),as important signals that regulate root elongation,were accumulated to higher levels in the rres1 mutant than the wild type after salt treatment.Measurement of monosaccharides in the cell wall showed that arabinose and xylose contents were decreased in the rres1 mutant under salt stress,and application of boric acid,which is required for the crosslinking of pectic polysaccharide rhamnogalacturonan-II(RG-II),largely rescued the root growth arrest of the rres1 mutant,suggesting that RRES1 participates in the maintenance of cell wall integrity under salt stress.GUS staining assay indicated that the RRES1 gene was expressed in leaves and weakly in root tip under normal conditions,but its expression was dramatically increased in leaves and roots after salt treatment.Together,our study reveals a novel mitochondrial protein that regulates root elongation under salt stress via the modulation of cell wall integrity,auxin accumulation,and ROS homeostasis.展开更多
Except in the Poaceae, little is known about the structures of the xyloglucans in the primary walls of monocotyledons. Xyloglucan structures in a range of monocotyledon species were examined. Wall preparations were is...Except in the Poaceae, little is known about the structures of the xyloglucans in the primary walls of monocotyledons. Xyloglucan structures in a range of monocotyledon species were examined. Wall preparations were isolated, extracted with 6 M sodium hydroxide, and the extracts treated with a xyloglucan-specific endo-(1→4)-β-glucanase preparation. The oligosaccharides released were analyzed by high-performance anion-exchange chromatography and by matrix-assisted laser-desorption ionization time-of-flight mass spectrometry. Oligosaccharide profiles of the non-commelinid monocotyledons were similar to those of most eudicotyledons, indicating the xyloglucans were fucogalactoxyloglucans, with a XXXG a core motif and the fucosylated units XXFG and XLFG. An exception was Lemna minor (Araceae), which yielded no fucosylated oligosaccharides and had both XXXG and XXGn core motifs. Except for the Arecales (palms) and the Dasypogonaceae, which had fucogalactoxyloglucans, the xyloglucans of the commelinid monocotyledons were structurally different. The Zingiberales and Commelinales had xyloglucans with both XXGn and XXXG core motifs; small proportions of XXFG units, but no XLFG units, were present. In the Poales, the Poaceae had xyloglucans with a XXGn core motif and no fucosylated units. In the other Poales families, some had both XXXG and XXGn core motifs, others had only XXXG; XXFG units were present, but XLFG units were not.展开更多
基金the National Natural Science Foundation of China(Nos.31971619 and 31901327)the Overseas Expertise Introduction Project for Discipline Innovation(111 Project D18008)the research foundation of Zhejiang A&F University(2018FR022),China.
文摘Dietary fiber(DF)is one of the major classes of nutrients for humans.It is widely distributed in the edible parts of natural plants,with the cell wall being the main DF-containing structure.DF content varies significantly in different plant species and organs,and the processing procedure can have a dramatic effect on the DF composition of plant-based foods.Given the considerable nutritional value of DF,a deeper understanding of DF in food plants,including its composition and biosynthesis,is fundamental to the establishment of a daily intake reference of DF and is also critical to molecular breeding programs for modifying DF content.In the past decades,plant cell wall biology has seen dramatic progress,and such knowledge is of great potential to be translated into DF-related food science research and may provide future research directions for improving the health benefits of food crops.In this review,to spark interdisciplinary discussions between food science researchers and plant cell wall biologists,we focus on a specific category of DF--cell wall carbohydrates.We first summarize the content and composition of carbohydrate DF in various plant-based foods,and then discuss the structure and biosynthesis mechanism of each carbohydrate DF category,in particular the respective biosynthetic enzymes.Health impacts of DF are highlighted,and finally,future directions of DF research are also briefly outlined.
文摘The plant cell wall is a complex 3D network composed of polysaccharides, lignin and proteins. The knowledge of the structure and content of each cell wall polymer is a prerequisite to understand their functions during plant development and adaptation but also to optimise their industrial applications. The analysis of cell wall compounds is complicated by their multiple molecular interactions. In this review, we present numerous methods to purify, characterise and quantify proteins, polysaccharides and lignin from the wall. Two kinds of approaches are detailed: the first presents in vitro methods which involve the breakdown of the molecular linkages between polymers thanking to chemical, physical and/or enzymatic treatments. The second approach describes in situ methods that allow the cell wall polymer characterisation thanking to many analytical techniques coupled with microscopy. If microscopy is the common point of all of them, their development is associated with improvement of analytical techniques, increasing their power of resolution.
文摘Resurrection fern has a unique ability to maintain cell wall integrity when the plant cell is desiccated. It uses proteins such as late embryogenesis proteins and heat shock proteins to maintain their cellular functions. The purpose of this experiment is to determine the effects of environmental stressors on the physiological response of the resurrection fern (Pleopeltis polypodioides). The physiological response of resurrection fern plants was subjected to various temperatures (-50°C, 0°C, 25°C, and 50°C) for 7 days. Results indicated that there was a significant difference between hydrated and desiccated ferns based on the temperature. Additionally, electrolyte leakage measurements confirmed cell damage following exposure to temperature extremes of -50°C and 50°C.
基金L.B.:EMBO postdoctoral fellowship ALTF 37-2022.S.P.acknowledges the financial aid of Villum Investigator(project ID:25915)DNRF Chair(DNRF155)+6 种基金Novo Nordisk L aureate(NNF190C0056076)Novo Nor-disk Emerging Investigator(NNF200C0060564)Novo Nordisk Data Sci-ence(NNF0068884)Lundbeck Foundation(experiment grant,R346-2020-1546)grantsK.E.H.F.:Novo Nordisk Foundation Industrial Biotechnology and Environmental Biotechnology Postdoctoral grant(NNF210C0071799)Villum Foundation Experiment grant (MIL50427)L.C.N.:EMBO postdoctoral fellowship ALTF 629-2021.
文摘All plant cells are surrounded by a cell wall that provides cohesion,protection,and a means of directional growth to plants.Cellulose microfibrils contribute the main biomechanical scaffold for most of these walls.The biosynthesis of cellulose,which typically is the most prominent constituent of the cell wall and therefore Earth’s most abundant biopolymer,is finely attuned to developmental and environmental cues.Our understanding of the machinery that catalyzes and regulates cellulose biosynthesis has substantially improved due to recent technological advances in,for example,structural biology and microscopy.Here,we provide a comprehensive overview of the structure,function,and regulation of the cellulose synthesis machinery and its regulatory interactors.We aim to highlight important knowledge gaps in the field,and outline emerging approaches that promise a means to close those gaps.
基金supported by the Biotechnology and Biological Sciences Research Council(Grant No.BB/M025918/1)National Natural Science Foundation of China(Grant No.32101656)+1 种基金Project of Guangxi Natural Science Foundation(Grant No.2020GXNSFDA297016)China Postdoctoral Science Foundation(Grant No.2021M691322).
文摘Fruit softening in tomato(Solanum lycopersicum)is closely associated with cell wall disassembly,which is brought about through the action of a range of cell wall structure-related enzymes and other proteins such as expansins.Xyloglucan endotransglucosylase/hydrolase(XTH)(EC 2.4.1.207 and/or EC 3.2.1.151)has been proposed to be key player involved in xyloglucan metabolism.SlXTH5 showed the highest expression level among all SlXTHs during tomato ripening.In this study,the role of SlXTH5 involved in tomato softening was investigated in CRISPR-based knockout mutants of SlXTH5.Loss-of-function of SlXTH5 in transgenic tomato lines resulted in slightly firmer fruit pericarp,but significantly decreased their color index compared with azygous wild type(WT)control fruits.Increased paste viscosity was detected in CRISPR mutants,indicating that the activity of SlXTH5 is responsible for maintaining cell wall structural integrity.Immunocytochemistry studies were performed using the monoclonal antibody probe LM25 to examine the localization and distribution of xyloglucan in the pericarp cells of the CRISPR mutant fruits.The data indicated more xyloglucan was retained in the pericarp of CRISPR mutant fruit than in WT control fruit.This study revealed the link between SlXTH5 and xyloglucan metabolism and indicated the potential of manipulating SlXTH5 to regulate fruit softening.
文摘Plant cell walls contain elaborate polysaccharide networks and regulate plant growth, development, mechanics, cell-cell communication and adhesion, and defense. Despite conferring rigidity to support plant structures, the cell wall is a dynamic extracellular matrix that is modified, reorganized, and degraded to tightly control its properties during growth and development. Far from being a terminal carbon sink, many wall polymers can be degraded and recycled by plant cells, either via direct re-incorporation by trans- glycosylation or via internalization and metabolic salvage of wall-derived sugars to produce new precur- sors for wall synthesis. However, the physiological and metabolic contributions of wall recycling to plant growth and development are largely undefined. In this review, we discuss long-standing and recent evi- dence supporting the occurrence of cell-wall recycling in plants, make predictions regarding the develop- mental processes to which wall recycling might contribute, and identify outstanding questions and emerging experimental tools that might be used to address these questions and enhance our understanding of this poorly characterized aspect of wall dynamics and metabolism.
基金supported by grants from the Fundamental Research Funds for the Central Universities Project , China (2013QC042)the Fundamental Research Funds for the 111 Project of Ministry of Education of China (B08032)the Starting Foundation for Changjiang Scholars Program of Ministry of Education of China (52204-14004)
文摘Among the potential non-food energy crops,the sugar-rich C4 grass sweet sorghum and the biomass-rich Miscanthus are increasingly considered as two leading candidates.Here,we outline the biological traits of these energy crops for largescale production in China.We also review recent progress on understanding of plant cell wall composition and wall polymer features of both plant species from large populations that affect both biomass enzymatic digestibility and ethanol conversion rates under various pretreatment conditions.We finally propose genetic approaches to enhance biomass production,enzymatic digestibility and sugar-ethanol conversion efficiency of the energy crops.
基金funded by the Division of Chemical Sciences, Geosciences, and Biosciences, Offce of Basic Energy Sciences of the U.S. Department of Energy through Grant DE‐FG02‐07ER15887funds from the National Science Foundation grant 0937323 provided salary support for F.G
文摘Root hairs and pollen tubes are formed through tip growth, a process requiring synthesis of new cell wall material and the precise targeting and integration of these components to a selected apical plasma membrane domain in the growing tips of these cells. Presence of a tip-focused calcium gradient, control of actin cytoskeleton dynamics, and formation and targeting of secretory vesicles are essential to tip growth. Similar to cells undergoing diffuse growth, cellulose, hemi-celluloses, and pectins are also deposited in the growing apices of tip-growing cells. However, differences in the manner in which these cell wall components are targeted and inserted in the expanding portion of tip-growing cells is reflected by the identification of elements of the plant cell wall synthesis machinery which have been shown to play unique roles in tip-growing cells. In this review, we summarize our current understanding of the tip growth process, with a particular focus on the subcellular targeting of newly synthesized cell wall components, and their roles in this form of plant cell expansion.
文摘Virus-induced gene silencing (VIGS) is a powerful genetic tool for rapid assessment of plant gene functions in the post-genomic era. Here, we successfully implemented a Tobacco Rattle Virus (TRV)-based VlGS system to study functions of genes involved in either primary or secondary cell wall formation in Nicotiana benthamiana plants. A 3-week post- VIGS time frame is sufficient to observe phenotypic alterations in the anatomical structure of stems and chemical composition of the primary and secondary cell walls. We used cell wall glycan-directed monoclonal antibodies to demonstrate that alteration of cell wall polymer synthesis during the secondary growth phase of VIGS plants has profound effects on the extractability of components from woody stem cell walls. Therefore, TRV-based VlGS together with cell wall component profiling methods provide a high-throughput gene discovery platform for studying plant cell wall formation from a bioenergy perspective.
基金the Leverhulme Foundation (sponsor reference F00158/CI)
文摘Transglycanases(endotransglycosylases) cleave a polysaccharide(donor-substrate) in mid-chain, and then transfer a portion onto another poly-or oligosaccharide(acceptor-substrate). Such enzymes contribute to plant cellwall assembly and/or re-structuring. We sought a general method for revealing novel homo- and hetero-transglycanases, applicable to diverse polysaccharides and oligosaccharides, separating transglycanase-generated3 Hpolysaccharides from unreacted3H-oligosaccharides—the former immobilized(on filter-paper, silica-gel or glassfiber),the latter eluted. On filter-paper, certain polysaccharides [e.g.(1!3, 1!4)-b-D-glucans] remained satisfactorily adsorbed when water-washed; others(e.g. pectins) were partially lost. Many oligosaccharides(e.g. arabinan-, galactan-, xyloglucan-based) were successfully eluted in appropriate solvents, but others(e.g. [3H]xylohexaitol, [3H]mannohexaitol[3H]cellohexaitol) remained immobile. On silica-gel, all3 Holigosaccharides left an immobile ‘ghost’ spot(contaminating any3H-polysaccharides), which was diminished but not prevented by additives e.g. sucrose or Triton X-100. The best stratum was glassfiber(GF), onto which the reactionmixture was dried then washed in 75% ethanol. Washing led to minimal loss or lateral migration of3H-polysaccharides if conducted by slow percolation of acidified ethanol. The effectiveness of GF-blotting was well demonstrated for Chara vulgaris transb-mannanase. In conclusion, our novel GF-blotting technique ef ficiently frees transglycanase-generated3H-polysaccharides from unreacted3H-oligosaccharides,enabling high-throughput screening of multiple postulated transglycanase activities utilising chemically diverse donorand acceptor-substrates.
文摘The triennial International Conference on Plant Cell Wall Biology has been held 5 times since it was initiated in the United States. PCWB2017 for the first time is organized in China. The conference was attended with more than 220 participants and featured with oral and poster presentations, reflecting the contemporarv status of plant cell wall studies.
文摘Xyloglucans in the non-lignified primary cell walls of different species of monocotyledons have diverse struc- tures, with widely varying proportions of oligosaccharide units that contain fucosylated side chains (F side chains). To determine whether fucosylated xyloglucans occur in all non-lignified walls in a range of monocotyledon species, we used immunofluorescence microscopy with the monoclonal antibody CCRC-M1. The epitope of this antibody, α-L-FUCp-(1 →2)- β-D-Galp, occurs in F side chains. In most non-commelinid monocotyledons, the epitope was found in all non-lignified walls. A similar distribution was found in the palm Phoenix canariensis, which is a member of the basal commelinid order Arecales. However, in the other commelinid orders Zingiberales, Commelinales, and Poales, the occurrence of the epitope was restricted, sometimes occurring in only the phloem walls, but often also in walls of other cell types including stomatal guard and subsidiary cells and raphide idioblasts. No epitope was found in the walls of the commelinids Tradescantia virginiana (Commelinaceae, Commelinales) and Zea mays (Poaceae, Poales), but it occurred in the phloem walls of two other Poaceae species, Lolium multiflorum and L. perenne. The distribution of the epitope is discussed in relation to xyloglucan structures in the different taxa. However, the functional significance of the restricted distributions is unknown.
文摘Research on the many aspects of the plant cell wall has experienced reiuvenation during the past few years. This is perhaps mainly due to the commercial interest in the chemical components of the cell wall that have potential for industrial use" Cellulose for fibers and together with hemicelluloses for bioethanol, lignin for plastics or biofuel, pectins as gel agents, let alone woody cell wall material for construction or pulp production and for intelligent materials for electronics - the new uses are mindboggling!
文摘The wood polysaccharide composition, a new analytical method, based on ionic liquid dissolution of low amount of biomass coupled with an ELISA essay of polysaccharides. In the present work, we synthesized and tested several imidazolium and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) based ILs for their ability to solubilize Douglas-fir wood while preserving the wall polymer integrity. The couple times-temperatures have been essayed for wood dissolution. Then their efficiency for wood biomass dissolution was compared to the impact of IL on storing and/or destroy polysaccharides. Thanks to the ELISA technique with a set of mAbs against epitopes of the main hemicellulose, pectin, and protein families of cell wall components. Wood destructuration at 80˚C with the 1-ethyl-3-methylimidazolium bromide represents a good compromise of wood dissolution efficiency and low polysaccharide destruction.
基金financially supported by the Max-Planck Gesellschaft,and Zengyu Liu by the Chinese Scholarship Council
文摘The cell wall provides external support of the plant cells, while the cytoskeletons including the microtubules and the actin filaments constitute an internal framework. The cytoskeletons contribute to the cell wall biosynthesis by spatially and temporarily regulating the transportation and deposition of cell wall components. This tight control is achieved by the dynamic behavior of the cytoskeletons, but also through the tethering of these structures to the plasma membrane. This tethering may also extend beyond the plasma membrane and impact on the cell wall, possibly in the form of a feedback loop. In this review, we discuss the linking components between the cytoskeletons and the plasma membrane, and/or the cell wall. We also discuss the prospective roles of these components in cell wall biosyn- thesis and modifications, and aim to provide a platform for further studies in this field.
基金supported by Changjiang Innovation Research Team (IRT1185)Fundamental Research Funds for the Central Universities
文摘Glucose (Glu) is involved in not only plant physiological and developmental events but also plant responses to abiotic stresses. Here, we found that the exogenous Glu improved root and shoot growth, reduced shoot cadmium (Cd) concentration, and rescued Cd-induced chlorosis in Arabidopsis thaliana (Columbia ecotype, Col-0) under Cd stressed conditions. Glucose increased Cd retained in the roots, thus reducing its translocation from root to shoot significantly. The most Cd retained in the roots was found in the hemicellulose 1. Glucose combined with Cd (Glu t Cd) treatment did not affect the content of pectin and its binding capacity of Cd while it increased the content of hemicelluloses 1 and the amount of Cd retained in it significantly. Furthermore, Leadmium Green staining indicated that more Cd was compartmented into vacuoles in Glu t Cd treatment compared with Cd treatment alone, which was in accordance with the significant upregulation of the expression of tonoplast-localized metal transporter genes, suggesting that com-partmentation of Cd into vacuoles also contributes to the Glu-alleviated Cd toxicity. Taken together, we demonstrated that Glu-alleviated Cd toxicity is mediated through increas-ing Cd fixation in the root cell wall and sequestration into the vacuoles.
文摘The CELLULOSE SYNTHASE-LIKE C (CSLC) family is an ancient lineage within the CELLULOSE SYNTHASE/CELLULOSE SYNTHASE-LIKE (CESA/CSL) polysaccharide synthase superfamily that is thought to have arisen before the divergence of mosses and vascular plants. As studies in the flowering plant Arabidopsis have suggested synthesis of the (1,4)-β-glucan backbone of xyloglucan (XyG), a wall polysaccharide that tethers adjacent cellulose microfibrils to each other, as a probable function for the CSLCs, CSLC function was investigated in barley (Hordeum vulgate L.), a species with low amounts of XyG in its walls. Four barley CSLCgenes were identified (designated HvCSLC1-4). Phylogenetic analysis reveals three well supported clades of CSLCs in flowering plants, with barley having representatives in two of these clades. The four barley CSLCs were expressed in various tissues, with in situ PCR detecting transcripts in all cell types of the coleoptile and root, including cells with primary and secondary cell walls. Co-expression analysis showed that HvCSLC3 was coordinately expressed with putative XyG xylosyltransferase genes. Both immuno-EM and membrane fractionation showed that HvCSLC2 was located in the plasma membrane of barley suspension-cultured cells and was not in internal membranes such as endoplasmic reticulum or Golgi apparatus. Based on our current knowledge of the sub-cellular locations of polysaccharide synthesis, we conclude that the CSLC family probably contains more than one type of polysaccharide synthase.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences,Grant XDB27040101(to J-K.Z.)Shanghai Pujiang Program,Grant 20PJ1414800(to C.Z.),and National Natural Science Foundation of China,Grant No.32070295(to C.Z.).
文摘Maintenance of cell wall integrity is of great importance not only for plant growth and development,but also for the adaptation of plants to adverse environments.However,how the cell wall integrity is modulated under salt stress is still poorly understood.Here,we report that a nuclear-localized Agenet domain-containing protein SWO1(SWOLLEN 1)is required for the maintenance of cell wall integrity in Arabidopsis under salt stress.Mutation in SWO1 gene results in swollen root tips,disordered root cell morphology,and root elongation inhibition under salt stress.The swo1 mutant accumulates less cellulose and pectin but more lignin under high salinity.RNA-seq and ChIP-seq assays reveal that SWO1 binds to the promoter of several cell wall-related genes and regulates their expression under saline conditions.Further study indicates that SWO1 interacts with importinɑIMPA1 and IMPA2,which are required for the import of nuclear-localized proteins.The impa1 impa2 double mutant also exhibits root growth inhibition under salt stress and mutations of these two genes aggravate the salt-hypersensitive phenotype of the swo1 mutant.Taken together,our data suggest that SWO1 functions together with importinɑto regulate the expression of cell wall-related genes,which enables plants to maintain cell wall integrity under high salinity.
基金supported by Shanghai Pujiang Program,Grant 20PJ1414800(to C.Z.)National Natural Science Foundation of China,Grant 32070295(to C.Z.)+1 种基金Strategic Priority Research Program of the Chinese Academy of Sciences,Grant XDB27040101(to J-K.Z.)Shanghai Agriculture Applied Technology Development Program,Grant G2020-01-01(to C.Z.).
文摘Maintenance of root elongation is beneficial for the growth and survival of plants under salt stress,but currently the cellular components involved in the regulation of root growth under high salinity are not fully understood.In this study,we identified an Arabidopsis mutant,rres1,which exhibited reduced root elongation under treatment of a variety of salts,including NaCl,NaNO3,KCl,and KNO3.RRES1 encodes a novel mitochondrial protein and its molecular function is still unknown.Under salt stress,the root meristem length was shorter in the rres1 mutant compared to the wild type,which was correlated with a reduced auxin accumulation in the mutant.Reactive oxygen species(ROS),as important signals that regulate root elongation,were accumulated to higher levels in the rres1 mutant than the wild type after salt treatment.Measurement of monosaccharides in the cell wall showed that arabinose and xylose contents were decreased in the rres1 mutant under salt stress,and application of boric acid,which is required for the crosslinking of pectic polysaccharide rhamnogalacturonan-II(RG-II),largely rescued the root growth arrest of the rres1 mutant,suggesting that RRES1 participates in the maintenance of cell wall integrity under salt stress.GUS staining assay indicated that the RRES1 gene was expressed in leaves and weakly in root tip under normal conditions,but its expression was dramatically increased in leaves and roots after salt treatment.Together,our study reveals a novel mitochondrial protein that regulates root elongation under salt stress via the modulation of cell wall integrity,auxin accumulation,and ROS homeostasis.
文摘Except in the Poaceae, little is known about the structures of the xyloglucans in the primary walls of monocotyledons. Xyloglucan structures in a range of monocotyledon species were examined. Wall preparations were isolated, extracted with 6 M sodium hydroxide, and the extracts treated with a xyloglucan-specific endo-(1→4)-β-glucanase preparation. The oligosaccharides released were analyzed by high-performance anion-exchange chromatography and by matrix-assisted laser-desorption ionization time-of-flight mass spectrometry. Oligosaccharide profiles of the non-commelinid monocotyledons were similar to those of most eudicotyledons, indicating the xyloglucans were fucogalactoxyloglucans, with a XXXG a core motif and the fucosylated units XXFG and XLFG. An exception was Lemna minor (Araceae), which yielded no fucosylated oligosaccharides and had both XXXG and XXGn core motifs. Except for the Arecales (palms) and the Dasypogonaceae, which had fucogalactoxyloglucans, the xyloglucans of the commelinid monocotyledons were structurally different. The Zingiberales and Commelinales had xyloglucans with both XXGn and XXXG core motifs; small proportions of XXFG units, but no XLFG units, were present. In the Poales, the Poaceae had xyloglucans with a XXGn core motif and no fucosylated units. In the other Poales families, some had both XXXG and XXGn core motifs, others had only XXXG; XXFG units were present, but XLFG units were not.