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1.
Golgi enzymes that synthesize plant cell wall polysaccharides: finding and evaluating candidates in the genomic era 总被引:8,自引:0,他引:8
Although the synthesis of cell wall polysaccharides is a critical process during plant cell growth and differentiation, many of the wall biosynthetic genes have not yet been identified. This review focuses on the synthesis of non-cellulosic matrix polysaccharides formed in the Golgi apparatus. Our consideration is limited to two types of plant cell wall biosynthetic enzymes: glycan synthases and glycosyltransferases. Classical means of identifying these enzymes and the genes that encode them rely on biochemical purification of enzyme activity to obtain amino acid sequence data that is then used to identify the corresponding gene. This type of approach is difficult, especially when acceptor substrates for activity assays are unavailable, as is the case for many enzymes. However, bioinformatics and functional genomics provide powerful alternative means of identifying and evaluating candidate genes. Database searches using various strategies and expression profiling can identify candidate genes. The involvement of these genes in wall biosynthesis can be evaluated using genetic, reverse genetic, biochemical, and heterologous expression methods. Recent advances using these methods are considered in this review. 相似文献
2.
Feruloyl-CoA:arabinoxylan-trisaccharide O-hydroxycinnamoyl transferase, which catalyzes the transfer of ferulic acid from Fer-CoA to arabinoxylan-trisaccharide in
the formation of feruloyl arabinoxylan-trisaccharide (Fer-AXX), has been found in an ionically bound fraction and a cytosol
fraction of suspension-cultured rice (Oriza sativa L. cv. Nipponbare) cells. Analysis of reaction products by high-performance liquid chromatography showed the formation of
product A, which is one of the transfer products having the same retention time as authentic Fer-AXX. Product A was purified
by reverse-phase chromatographies to characterize its structure. The isolated product A showed the same ultraviolet spectrum
and molecular weight on fast atom bombardment mass spectrometric analysis as those of authentic Fer-AXX. Alakaline saponification
of product A released ferulic acid and oligosaccharide. The released oligosaccharide consisted of arabinose and xylose in
a molar ratio of 1:2. These results support the identity of product A as feruloylated arabinoxylan-trisaccharide and show
the existence of a feruloyltransferase catalyzing the feruloylation of a hemicellulosic fragment.
Received: 14 July 2000 / Accepted: 22 August 2000 相似文献
3.
Kazuyuki Wakabayashi Takayuki Hoson Seiichiro Kamisaka 《Journal of plant research》1997,110(3):311-316
Effects of polyethylene glycol (PEG)-induced osmotic stress on the mechanical properties of cell walls and the levels of their
components were investigated along intact wheat (Triticum aestivum L.) coleoptiles. Stress-relaxation analysis showed that the cell walls of stressed coleoptiles were loosened as compared
with those of unstressed ones not only in the apical but in the basal regions. The amounts of wall-bound ferulic acid (FA)
and diferulic acid (DFA) of stressed coleoptiles were substantially lower than those of unstressed ones in all regions. The
cellulose and hemicellulose contents increased toward the coleoptile base. Osmotic stress reduced the cellulose content in
the basal region but it slightly affected the hemicellulose content. The molecular weight of hemicellulose in the apical region
of stressed coleoptiles was higher than that of unstressed ones, while that in the basal region was almost the same in both
coleoptiles. FA, DFA and cellulose contents correlated with the cell wall mechanical property. The amount and molecular weight
of hemicellulose, however, did not correlate. These results suggest that the reduced levels of FA and DFA in all regions and
cellulose in the basal region of wheat coleoptiles are involved in maintaining the cell wall extensibility under osmotic stress. 相似文献
4.
Cell walls from suspension cultures of parsley (Petroselinum crispum L.) induced with a fungal elicitor contained hydroxycinnamoyl ester groups presumably not bound to pectic polysaccharides.
Extracts from these cells were separated into a range of low-molecular-weight compounds containing esterified ferulic and
p-coumaric acid as well as glucose and some arabinose. Similar compounds also accumulated extracellularly in elicited cultures
but only in the presence of the peroxidase inhibitor ascorbate, suggesting that they may represent the exported precursors
for cell wall hydroxycinnamic acids. From cultures elicited in the presence of ascorbate, alkali released from the cell walls
more ferulic, p-coumaric and p-hydroxybenzoic acid, as well as p-hydroxybenzaldehyde and vanillin, indicating that the corresponding wall phenolics can all become further cross-linked.
Received: 6 September 1996 / Revision received: 10 March 1997 / Accepted: 10 April 1997 相似文献
5.
Alkaline hydrolysis liberated ferulic and diferulic acid from polysaccharides of the Avena coleoptile ( Avena sativa L. cv. Victory I) cell walls. The amount of the two phenolic acids bound to cell walls increased substantially at day 4–5 after sowing, when the growth rate of the coleoptile started to decrease. The level of these acids was almost constant from the tip to base in 3-day-old coleoptiles, but increased toward the basal zone in 4- and 5-day-old ones. The ratio of diferulic acid to ferulic acid was almost constant irrespective of coleoptile age and zone. An increase in the amount of ferulic and diferulic acids bound to cell wall polysaccharides correlated with a decrease in extensibility and with an increase in minimum stress-relaxation time and relaxation rate of the cell wall. The level of lignin in the cellulose fraction increased as coleoptiles aged, but this increase did not correlate with changes in mechanical properties of the cell walls. These results suggest that ferulic acid, ester-linked to cell wall polysaccharides, is oxidized to give diferulic acid, which makes the cell wall mechanically rigid by cross-linking matrix polysaccharides and results in limited cell extension growth. In addition, it is probable that the step of feruloylation of cell wall polysaccharides is rate-limiting in the formation of in-termolecular bridges by diferulic acid in Avena coleoptile cell walls. 相似文献
6.
Biosynthesis of the cell wall in carrot cells (Daucus carota L.) cultured in a synthetic liquid medium was studied by measuring the incorporation of radioactive glucose and myo-inositol (MI). When the cells were fed with [14C]glucose in the presence of 0.01% MI, the label soon appeared in the neutral sugars in the cell wall but little radioactivity was found in the uronic-acid residues even after a prolonged incubation. On the other hand, radioactivity derived from [3H]MI was found to be distributed among uronic acids and pentoses but not in the hexose residues in the wall. The data indicate that MI is an important intermediate for the synthesis of acidic sugars in the wall of cultured carrot cells.Abbreviation MI
myo-inositol 相似文献
7.
Intracellular feruloylation of pectic polysaccharides 总被引:2,自引:2,他引:0
Stephen C. Fry 《Planta》1987,171(2):205-211
The pectic polysaccharides of spinach cell walls carry feruloyl groups on arabinose and galactose residues. The following experiments were designed to discover whether the arabinose residues are feruloylated intra-or extracellularly. Cultured spinach cells started to incorporate exogenous [3H]arabinose into polymers at a linear rate after a lag period of approx. 3–4 min, although radioactive polysaccharides and extensin did not start to appear outside the plasmalemma until after an approx. 25-min lag. In the same cells, polysaccharide-bound feruloyl-[3H]arabinose units starded to accumulate radioactivity at a linear rate after a lag period of approx. 4–5 min. Therefore, arabinose residues of polysaccharides began to be feruloylated while still intracellular. The rate of formation of polysaccharide-bound feruloyl-[3H]arabinose units did not appreciably increase after 25 min, showing that any additional extracellular feruloylation of the polysaccharide was relatively slow. This conclusion was supported by two different types of pulse-chase experiments, one of which was designed to detect feruloylation of polysaccharides up to 6 d after synthesis.Abbreviations Ara2
3-O–-L-arabinopyranosyl-L-arabinose
- BAW
butan-1-ol/acetic acid/water (12:3:5, by vol.)
- BEW
butan-1-ol/ethanol/water (20:5:11, by vol.)
- EPW
ethyl acetate/pyridine/water (8:2:1, by vol.)
- Fer-Ara2
3-O–(3-O–feruloyl--L-arabinopyranosyl)-L-arabinose
- Fer-Gal2
4-O–(6-O–feruloyl--D-galactopyranosyl)-D-galactose 相似文献
8.
Changes in the limiting porosity of cell walls, i.e. the size limit for permeation of neutral molecules through the wall,
were studied in several higher-plant cell-suspension cultures. For this purpose, samples of biomass fixed at different cultivation
times were investigated using a method based on size-exclusion chromatography of polydisperse dextrans before and after equilibration
with the extracted cell clusters. In suspension cultures of Chenopodium album L., Dioscorea deltoidea Wall. and Medicago sativa L., the mean size limit (MSL; critical Stokes' radius for exclusion of neutral polymers from half of the intracellular space)
was found to vary between 2.4 and 3.8 nm. It decreased significantly during transition from the growth phase to the stationary
phase. In the case of the C. album culture this change was found to be irrespective of whether sucrose in the medium was completely depleted at the end of the
growth phase or not. The MSL was kept constant for long periods of the stationary phase if cell viability was maintained by
repeated sucrose supplement. In a suspension strain of Triticum aestivum L., the MSL of cell wall permeation was comparatively small (1.75 nm) and remained constant during all cultivation phases.
Relations between limiting porosity and cell wall growth, loss of pectic compounds to the medium, cross-linking activities
and cell wall stiffening are discussed.
Received: 19 December 1996 / Accepted: 23 April 1997 相似文献
9.
Primary cell wall metabolism: tracking the careers of wall polymers in living plant cells 总被引:27,自引:1,他引:27
Stephen C. Fry 《The New phytologist》2004,161(3):641-675
10.
11.
12.
Polysaccharide analysis using carbohydrate gel electrophoresis: a method to study plant cell wall polysaccharides and polysaccharide hydrolases. 总被引:5,自引:0,他引:5
Florence Goubet Peter Jackson Michael J Deery Paul Dupree 《Analytical biochemistry》2002,300(1):53-68
A method to characterize plant cell wall polysaccharides is presented. The complexity of the polymer structures and the large number of different charged and uncharged monosaccharides that make up plant polysaccharides have previously made analysis technically demanding and laborious. Polysaccharide analysis using carbohydrate gel electrophoresis (PACE) relies on derivatization of reducing ends of sugars and oligosaccharides with a fluorophore, followed by electrophoresis under optimized conditions in polyacrylamide gels. We show that PACE is a sensitive and simple tool for studying the monosaccharide composition of polysaccharides and of cell wall preparations. In combination with specific hydrolases, it can be used to analyze the structure of polysaccharides. Moreover, the specificity and kinetics of the plant polysaccharide hydrolases themselves can be quickly and effectively studied. PACE can detect as little as 500 fmol of monosaccharides and 100 fmol of oligosaccharides, and it is fast and quantitative. 相似文献
13.
采用水培法比较4种禾本科植物水稻(Oryza sativa L.)、玉米(Zea mays L.)、高粱(Sorghum bicolor(L.)Moench)和小麦(Triticum aestivum L.)8个基因型的抗铝(Al)能力,并对他们在Al积累后细胞壁的多糖组分进行分析。结果显示,在5~200 μmol/L Al处理下,水稻抗Al能力较强,而小麦抗Al能力较弱。在50 μmol/L Al处理下,小麦根尖的果胶和半纤维素1含量的增幅明显高于水稻。水稻基因型‘日本晴’与‘浙辐802’的细胞壁Al含量分别占根尖总Al含量的78.7%和91.6%;小麦基因型‘扬麦18’与‘扬麦16’Al含量分别占根尖总Al含量的64.9%和72.1%。Al吸附-解吸实验结果显示,小麦根尖细胞壁上Al的吸附量高于水稻。研究结果表明,细胞壁是Al积累的主要部位,对Al敏感的水稻和小麦基因型细胞壁中的Al主要分布在果胶中;而对Al耐性较强的水稻和小麦基因型细胞壁中的Al主要分布在半纤维素1中。 相似文献
14.
The plant cell wall is composed of multiple biopolymers, representing one of the most complex structural networks in nature. Hundreds of genes are involved in building such a natural masterpiece. However, the plant cell wall is the least understood cellular structure in plants. Due to great progress in plant functional genomics,manyachievementshavebeenmadein uncovering cell wall biosynthesis, assembly, and architecture, as well as cell wall regulation and signaling. Such information has significantly advanced our understanding of the roles of the cell wall in many biological and physiological processes and has enhanced our utilization of cell wall materials. The use of cutting-edge technologies such as single-molecule imaging,nuclear magnetic resonance spectroscopy, and atomic force microscopy has provided much insight into the plant cell wall as an intricate nanoscale network, opening up unprecedented possibilities for cell wall research. In this review,we summarize the major advances made in understanding the cell wall in this era of functional genomics, including the latest findings on the biosynthesis, construction, and functions of the cell wall. 相似文献
15.
Boron and calcium, essential inorganic constituents of pectic polysaccharides in higher plant cell walls 总被引:11,自引:0,他引:11
Among 16 essential elements of higher plants, Ca2+ and B have been termed as apoplastic elements. This is mainly because of their localization in cell walls, however, it has
turned to be highly likely that these two elements significantly contribute to maintain the integrity of cell walls through
binding to pectic polysaccharides.
Boron in cell walls exclusively forms a complex with rhamnogalacturonan II (RG-II), and the B-RG-II complex is ubiquitous
in higher plants. Analysis of the structure of the B-RG-II complex revealed that the complex contains two molecules boric
acid, two molecules Ca2+ and two chains of monomeric RG-II. This result indicates that pectic chains are cross-linked covalently with boric acid at
their RG-II regions. The complex was reconstitutedin vitro only by mixing monomeric RG-II and boric acid, however, the complex decomposed spontaneously unless Ca2+ was supplemented. Furthermore, the native complex decomposed when it was incubated withtrans-1,2-diaminocyclohexane-N, N, N′, N′-tetraacetic acid (CDTA) which chelates Ca2+.
When radish root cell walls were washed with a buffered 1.5% (w/v) sodium dodesyl sulfate (SDS) solution (pH 6.5), 96%, 13%
and 6% of Ca2+, B and pectic polysaccharides of the cell walls, respectively, were released and the cell wall swelled twice. Subsequent
extraction with 50 mM CDTA (pH 6.5) of the SDS-washed cell walls further released 4%, 80% and 61% of Ca2+, B and pectic polysaccharides, respectively. Pectinase hydrolysis of the SDS-treated cell walls yielded a B-RG-II complex
and almost all the remaining Ca2+ was recovered in the complex. This result suggests that cell-wall bound Ca2+ is divided into at least two fractions, one anchors the CDTA-soluble pectic polysaccharides into cell walls together with
B, and the other may control the properties of the pectic gel.
These studies demonstrate that B functions to retain CDTA-soluble pectic polysaccharides in cell walls through its binding
to the RG-II regions in collaboration with Ca2+. 相似文献
16.
A microsomal preparation from suspension-cultured potato stem cells (Solanum tuberosum L. cv. AZY) was incubated with [14C]acetyl-CoA resulting in a precipitable radiolabeled product. Analysis of the product revealed that it consisted mostly of
acetylated proteins and cell wall polysaccharides, including xyloglucan, homogalacturonan and rhamnogalacturonan I. Thus,
acetyl-CoA is a donor-substrate for the O-acetylation of wall polysaccharides. A rhamnogalacturonan acetylesterase was used to develop an assay to measure and characterize
rhamnogalacturonan O-acetyl transferase activity in the microsomal preparation. Using this assay, it was shown that the transferase activity was
highest during the linear growth phase of the cells, had a pH-optimum at pH 7.0, a temperature optimum at 30 °C, an apparent
K
m of 35 μM and an apparent V
max of 0.9 pkat per mg protein. Further analysis of the radiolabeled acetylated product revealed that it had a molecular mass
>500 kDa.
Received: 3 July 1999; Accepted: 27 September 1999 相似文献
17.
Kerry Hosmer Caffall 《Carbohydrate research》2009,344(14):1879-1900
Plant cell walls consist of carbohydrate, protein, and aromatic compounds and are essential to the proper growth and development of plants. The carbohydrate components make up ∼90% of the primary wall, and are critical to wall function. There is a diversity of polysaccharides that make up the wall and that are classified as one of three types: cellulose, hemicellulose, or pectin. The pectins, which are most abundant in the plant primary cell walls and the middle lamellae, are a class of molecules defined by the presence of galacturonic acid. The pectic polysaccharides include the galacturonans (homogalacturonan, substituted galacturonans, and RG-II) and rhamnogalacturonan-I. Galacturonans have a backbone that consists of α-1,4-linked galacturonic acid. The identification of glycosyltransferases involved in pectin synthesis is essential to the study of cell wall function in plant growth and development and for maximizing the value and use of plant polysaccharides in industry and human health. A detailed synopsis of the existing literature on pectin structure, function, and biosynthesis is presented. 相似文献
18.
Cione E Tucci P Senatore V Perri M Trombino S Iemma F Picci N Genchi G 《Journal of bioenergetics and biomembranes》2008,40(1):19-26
Ferulic acid plays a chemopreventive role in cancer by inducing tumor cells apoptosis. As mitochondria play a key role in
the induction of apoptosis in many cells types, here we investigate the mitochondrial permeability transition (MPT) and the
release of cytochrome c induced by ferulic acid and its esters in rat testes mitochondria, in TM-3 and MLTC-1 cells. While ferulic acid, but not
its esters, induced MPT and cytochrome c release in rat testes isolated mitochondria, in TM-3 cells we found that both ferulic acid and its esters induced cytochrome
c release from mitochondria in a dose-dependent manner, suggesting a potential target of these compounds in the induction of
cell apoptosis. The apoptosis induced by ferulic acid is therefore associated with the mitochondrial pathway involving cytochrome
c release and caspase-3 activation.
Cione and Tucci have equally contributed to this article. 相似文献
19.
A sustainable bioeconomy that includes increased agricultural productivity and new technologies to convert renewable biomass to value-added products may help meet the demands of a growing world population for food, energy and materials. The potential use of plant biomass is determined by the properties of the cell walls, consisting of polysaccharides, proteins, and the polyphenolic polymer lignin. Comprehensive knowledge of cell wall glycan structure and biosynthesis is therefore essential for optimal utilization. However, several areas of plant cell wall research are hampered by a lack of available pure oligosaccharide samples that represent structural features of cell wall glycans. Here, we provide an update on recent chemical syntheses of plant cell wall oligosaccharides and their application in characterizing plant cell wall-directed antibodies and carbohydrate-active enzymes including glycosyltransferases and glycosyl hydrolases, with a particular focus on glycan array technology. 相似文献
20.
Summary Membranes from etiolated maize seedlings were isolated using sucrose gradients for in vitro studies of polysaccharide synthesis. Following downward centrifugation, flotation centrifugation improved the purity of membrane fractions, in particular the Golgi apparatus. Based on naphthylphthalamic acid binding to plasma membrane and inosine-5-diphosphatase activity in Golgi apparatus, flotation centrifugation removed about 70% of the plasma membrane which cosedimented with the Golgi apparatus in downward centrifugation. The addition of chelators during flotation centrifugation allowed separation of the Golgi apparatus from endoplasmic reticulum, as indicated by NADH cytochromec reductase activity. Glucan and xylan synthase activities were measured as the radioactivity incorporated from either UDP-14C-glucose or UDP-14C-xylose into 80% ethanol insoluble materials. Glucan synthase activity at a substrate concentration of 1 mM UDP-glucose without CaCl2 was greatest in fractions enriched in Golgi apparatus, but in the presence of 3 mM CaCl2 the activity was greatest in fractions enriched in plasma membrane. Glucan synthase activity at a substrate concentration of 10M UDP-glucose in the presence of 3 mM MnCl2 was greatest in fractions enriched in plasma membrane, but was also high in fractions enriched in Golgi apparatus. Xylan synthase activity, at a substrate concentration of 1 M UDP-xylose in the presence of 3 mM MnCl2, was greatest in fractions enriched in Golgi apparatus. To further characterize these synthase reactions, the glycosyl linkages of the products formed were analyzed with a gas chromatograph coupled to a radiogas proportional counter. With the substrate, UDP-14C-glucose, and fractions enriched in Golgi apparatus, both (13)- and (14)-radioactive glucosyl linkages were formed, whereas the main linkage formed by fractions enriched in plasma membrane was (13)-glucosyl. With the substrate, UDP-14C-xylose, mostly (14)-xylosyl and some terminal-xylosyl linkages were formed by fractions enriched in Golgi apparatus. Only xylan synthase activity copurified with Golgi apparatus and, because plasma membrane lacked this activity, xylan synthase may be used as a reasonable indicator of Golgi apparatus.Abbreviations ATP
adenosine-5-triphosphate
- CR
crude fraction from downward centrifugation
- FL
purified fraction from flotation centrifugation
- GC
gas chromatography
- GC-RPC
gas chromatography-radiogas proportional counting
- IDP
inosine-5-disphosphate
- NPA
naphthylphthalamic acid
- UDP
uridine-5-diphosphate
- TEM
transmission electron microscopy 相似文献