scholarly journals Cell wall polysaccharide biosynthesis and related metabolism in elicitor-stressed cells of French bean (Phaseolus vulgaris L.)

1995 ◽  
Vol 306 (3) ◽  
pp. 745-750 ◽  
Author(s):  
D Robertson ◽  
B A McCormack ◽  
G P Bolwell
Keyword(s):  
Cell Wall ◽  
Phaseolus Vulgaris ◽  
Time Course ◽  
Glucose Dehydrogenase ◽  
French Bean ◽  
Primary Cell Wall ◽  
Cell Wall Polysaccharide ◽  
Phaseolus Vulgaris L ◽  
Glucan Synthase ◽  
Elicitor Treatment

Enzyme activities involved in quantitative and qualitative flux of sugars into cell wall polysaccharides were determined following elicitor treatment of suspension cultured cells of French bean (Phaseolus vulgaris L.). Two subsets of activities were examined: the first were involved in synthesis and metabolism of UDP-glucose and the provision of the pool of UDP-sugars, and the second a selection of membrane-bound glycosyltransferases involved in the synthesis of pectins, hemicelluloses and glucans of the primary cell wall. Of the first group, only UDP-glucose dehydrogenase (EC 1.1.1.22) showed any significant induction in response to elicitor treatment, sucrose synthase (EC 2.4.1.13), UDP-glucuronate decarboxylase (EC 4.1.1.35), UDP-glucose and UDP-xylose 4-epimerases (EC 5.1.3.2 and EC 5.1.3.5 respectively) did not change in activity significantly over the time course. In contrast, enzymes of the second group showed a more complex response. Callose synthase (glucan synthase II, EC 2.4.1.12) increased in activity, as has been shown in other systems, while arabinan synthase (EC 2.4.1.-), xylan synthase (EC 2.4.1.72), xyloglucan synthase (EC 2.4.1.72) and glucan synthase I (EC 2.4.1.12) activities were rapidly depleted from membranes within 3 h following elicitor action. This rapid turnover of activity was striking, indicating that the half-life of such enzymes can be short and that elicitor action causes substantial perturbation of some membrane activities. Glucan synthase I activity appears to increase in the later stages over the time period measured, indicating some recovery of this metabolism.

scholarly journals Synthesis of dehydrogenation polymers of ferulic acid with high specificity by a purified cell-wall peroxidase from French bean (Phaseolus vulgaris L.)

1994 ◽  
Vol 299 (3) ◽  
pp. 747-753 ◽  
Author(s):  
A Zimmerlin ◽  
P Wojtaszek ◽  
G P Bolwell
Keyword(s):  
Cell Wall ◽  
Phaseolus Vulgaris ◽  
Ferulic Acid ◽  
Cultured Cells ◽  
Gel Filtration ◽  
High Specificity ◽  
French Bean ◽  
Good Evidence ◽  
Ionization Mass ◽  
Phaseolus Vulgaris L

A cationic (pI 8.3) wall-bound peroxidase has been purified to homogeneity from suspension-cultured cells of French bean (Phaseolus vulgaris L.). The enzyme was a glycoprotein and its M(r) was 46,000 as determined by SDS/Page and h.p.l.c. gel filtration. It was localized biochemically to microsomes and the cell wall, and the latter subcellular distribution was confirmed by immunogold techniques. The native enzyme showed absorption maxima at 403, 500 and 640 nm, with an RZ (A405/A280) of 3.3. The peroxidase oxidized guaïacol and natural phenolic acids. By desorption-chemical-ionization mass spectrometry the enzyme was found to oxidize the model compound, ferulic acid, into dehydrodiferulic acid. Kinetics studies indicated an apparent Km of 113.3 +/- 22.9 microM and a Vmax of 144 mumol.min-1.nmol-1 of protein at an H2O2 concentration of 100 microM. In comparison with a second French-bean peroxidase (FBP) and horseradish peroxidase, as a model, it acted with a 6-10-fold higher specificity in this capacity. It is a member of the peroxidase superfamily of bacterial, fungal and plant haem proteins by virtue of its highly conserved amino acid sequence within the proximal and distal haem-binding sites. This is good evidence that this particular FBP may function in constructing covalent cross-linkages in the wall during development and response to pathogens.

Interactions of the nonhost French bean plant (Phaseolus vulgaris) with parasitic and saprophytic fungi. III. Cytologically detectable responses

1989 ◽  
Vol 67 (3) ◽  
pp. 676-686 ◽  
Author(s):  
Myriam R. Fernandez ◽  
Michèle C. Heath
Keyword(s):  
Cell Wall ◽  
Phaseolus Vulgaris ◽  
General Feature ◽  
Fungal Spores ◽  
French Bean ◽  
Cell Necrosis ◽  
Phaseolus Vulgaris L ◽  
Fungal Cell ◽  
Parasitic Fungi ◽  
Nonhost Plant

Cytologically detectable responses of the nonhost French bean (Phaseolus vulgaris L. cv. Pinto) to saprophytic and parasitic fungi were examined when fungal spores were introduced into heated or unheated leaves via wounds or by injection. Although similar types of responses were observed in interactions with all the fungi, some of these responses were characteristic of each group (saprophytes vs. parasites) in the frequency and (or) extent with which they were elicited. Differences in responses between and within each of these groups of fungi were more related to their degree of adaptation for parasitism than to their taxonomic relationships. Certain responses that were typically elicited by the saprophytes occurred to a lesser extent in tissue responding to the parasites, suggesting that the ability to not trigger, or suppress, these responses may be a general feature of parasitic fungi. None of the fungi elicited significant levels of plant cell necrosis, and for two of the saprophytes, dead spores elicited a lower frequency of responses than live ones. The data indicate that many of the responses of a nonhost plant to living fungi may be the result of reactions to fungal activity rather than to constitutive recognition molecules such as components of the fungal cell wall.

scholarly journals UDP-glucose dehydrogenases of maize: a role in cell wall pentose biosynthesis

2005 ◽  
Vol 391 (2) ◽  
pp. 409-415 ◽  
Author(s):  
Anna Kärkönen ◽  
Alain Murigneux ◽  
Jean-Pierre Martinant ◽  
Elodie Pepey ◽  
Christophe Tatout ◽  
...  
Keyword(s):  
Cell Wall ◽  
Sequence Similarity ◽  
Glucose Dehydrogenase ◽  
Soya Bean ◽  
Amino Acid Sequences ◽  
Cell Wall Polysaccharide ◽  
Polysaccharide Biosynthesis ◽  
Polysaccharide Synthesis ◽  
Ethanol Dehydrogenase ◽  
Adh Activity

UDPGDH (UDP-D-glucose dehydrogenase) oxidizes UDP-Glc (UDP-D-glucose) to UDP-GlcA (UDP-D-glucuronate), the precursor of UDP-D-xylose and UDP-L-arabinose, major cell wall polysaccharide precursors. Maize (Zea mays L.) has at least two putative UDPGDH genes (A and B), according to sequence similarity to a soya bean UDPGDH gene. The predicted maize amino acid sequences have 95% similarity to that of soya bean. Maize mutants with a Mu-element insertion in UDPGDH-A or UDPGDH-B were isolated (udpgdh-A1 and udpgdh-B1 respectively) and studied for changes in wall polysaccharide biosynthesis. The udpgdh-A1 and udpgdh-B1 homozygotes showed no visible phenotype but exhibited 90 and 60–70% less UDPGDH activity respectively than wild-types in a radiochemical assay with 30 μM UDP-glucose. Ethanol dehydrogenase (ADH) activity varied independently of UDPGDH activity, supporting the hypothesis that ADH and UDPGDH activities are due to different enzymes in maize. When extracts from wild-types and udpgdh-A1 homozygotes were assayed with increasing concentrations of UDP-Glc, at least two isoforms of UDPGDH were detected, having Km values of approx. 380 and 950 μM for UDP-Glc. Leaf and stem non-cellulosic polysaccharides had lower Ara/Gal and Xyl/Gal ratios in udpgdh-A1 homozygotes than in wild-types, whereas udpgdh-B1 homozygotes exhibited more variability among individual plants, suggesting that UDPGDH-A activity has a more important role than UDPGDH-B in UDP-GlcA synthesis. The fact that mutation of a UDPGDH gene interferes with polysaccharide synthesis suggests a greater importance for the sugar nucleotide oxidation pathway than for the myo-inositol pathway in UDP-GlcA biosynthesis during post-germinative growth of maize.

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