scholarly journals Pectin methylesterase, metal ions and plant cell-wall extension. The role of metal ions in plant cell-wall extension

1991 ◽  
Vol 279 (2) ◽  
pp. 351-354 ◽  
Author(s):  
A M Moustacas ◽  
J Nari ◽  
M Borel ◽  
G Noat ◽  
J Ricard
Keyword(s):  
Cell Wall ◽  
Metal Ions ◽  
Plant Cell ◽  
Electrostatic Potential ◽  
Metal Ion ◽  
Plant Cell Wall ◽  
Pectin Methylesterase ◽  
Ion Concentration ◽  
Cell Wall Extension ◽  
Wall Loosening

The study of pectin methylesterase and wall-loosening enzyme activities in situ, as well as the estimation of the electrostatic potential of the cell wall, suggest a coherent picture of the role played by metal ions and pH in cell-wall extension. Cell-wall growth brings about a decrease of local proton concentration because the electrostatic potential difference (delta psi) of the wall decreases. This in turn activates pectin methylesterase, which restores the initial delta psi value. This process is amplified by the attraction of metal ions in the polyanionic cell-wall matrix. The amplification process is basically due to the release of enzyme molecules that were initially bound to ‘blocks’ of carboxy groups. This increase of metal-ion concentration also results in the activation of wall-loosening enzymes. Moreover, the apparent ‘inhibition’ of pectin methylesterase by high salt concentrations may be considered as a device which prevents the electrostatic potential from becoming too high.

scholarly journals Pectin methylesterase, metal ions and plant cell-wall extension. Hydrolysis of pectin by plant cell-wall pectin methylesterase

1991 ◽  
Vol 279 (2) ◽  
pp. 343-350 ◽  
Author(s):  
J Nari ◽  
G Noat ◽  
J Ricard
Keyword(s):  
Cell Wall ◽  
Metal Ions ◽  
Plant Cell ◽  
Plant Cell Wall ◽  
Direct Interaction ◽  
Enzyme Reaction ◽  
Pectin Methylesterase ◽  
High Concentrations ◽  
Enzyme Molecules ◽  
Hydrolysis Of

The hydrolysis of p-nitrophenyl acetate catalysed by pectin methylesterase is competitively inhibited by pectin and does not require metal ions to occur. The results suggest that the activastion by metal ions may be explained by assuming that they interact with the substrate rather than with the enzyme. With pectin used as substrate, metal ions are required in order to allow the hydrolysis to occur in the presence of pectin methylesterase. This is explained by the existence of ‘blocks’ of carboxy groups on pectin that may trap enzyme molecules and thus prevent the enzyme reaction occurring. Metal ions may interact with these negatively charged groups, thus allowing the enzyme to interact with the ester bonds to be cleaved. At high concentrations, however, metal ions inhibit the enzyme reaction. This is again understandable on the basis of the view that some carboxy groups must be adjacent to the ester bond to be cleaved in order to allow the reaction to proceed. Indeed, if these groups are blocked by metal ions, the enzyme reaction cannot occur, and this is the reason for the apparent inhibition of the reaction by high concentrations of metal ions. Methylene Blue, which may be bound to pectin, may replace metal ions in the ‘activation’ and ‘inhibition’ of the enzyme reaction. A kinetic model based on these results has been proposed and fits the kinetic data very well. All the available results favour the view that metal ions do not affect the reaction through a direct interaction with enzyme, but rather with pectin.

scholarly journals Post-Synthetic Reduction of Pectin Methylesterification Causes Morphological Abnormalities and Alterations to Stress Response in Arabidopsis thaliana

Plants ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1558
Author(s):  
Nathan T. Reem ◽  
Lauran Chambers ◽  
Ning Zhang ◽  
Siti Farah Abdullah ◽  
Yintong Chen ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Cell Wall ◽  
Plant Cell ◽  
Cell Walls ◽  
Plant Cell Wall ◽  
Normal Growth ◽  
Pectin Methylesterase ◽  
Dwarf Phenotype ◽  
Response To Stress ◽  
Defense Response Genes

Pectin is a critical component of the plant cell wall, supporting wall biomechanics and contributing to cell wall signaling in response to stress. The plant cell carefully regulates pectin methylesterification with endogenous pectin methylesterases (PMEs) and their inhibitors (PMEIs) to promote growth and protect against pathogens. We expressed Aspergillus nidulans pectin methylesterase (AnPME) in Arabidopsis thaliana plants to determine the impacts of methylesterification status on pectin function. Plants expressing AnPME had a roughly 50% reduction in methylester content compared with control plants. AnPME plants displayed a severe dwarf phenotype, including small, bushy rosettes and shorter roots. This phenotype was caused by a reduction in cell elongation. Cell wall composition was altered in AnPME plants, with significantly more arabinose and significantly less galacturonic acid, suggesting that plants actively monitor and compensate for altered pectin content. Cell walls of AnPME plants were more readily degraded by polygalacturonase (PG) alone but were less susceptible to treatment with a mixture of PG and PME. AnPME plants were insensitive to osmotic stress, and their susceptibility to Botrytis cinerea was comparable to wild type plants despite their compromised cell walls. This is likely due to upregulated expression of defense response genes observed in AnPME plants. These results demonstrate the importance of pectin in both normal growth and development, and in response to biotic and abiotic stresses.

Metal ion effects on hydraulic conductivity of bacterial cellulose–pectin composites used as plant cell wall analogs

2010 ◽  
Vol 138 (2) ◽  
pp. 205-214 ◽  
Author(s):  
Brigid A. McKenna ◽  
Peter M. Kopittke ◽  
J. Bernhard Wehr ◽  
F. Pax C. Blamey ◽  
Neal W. Menzies
Keyword(s):  
Cell Wall ◽  
Hydraulic Conductivity ◽  
Plant Cell ◽  
Metal Ion ◽  
Plant Cell Wall ◽  
Ion Effects ◽  
Metal Ion Effects

scholarly journals Pb induces plant cell wall modifications - in particular - the increase of pectins able to bind metal ions level

2013 ◽  
Vol 1 ◽  
pp. 26008 ◽  
Author(s):  
M. KrzesВowska ◽  
I. Rabęda ◽  
M. Lewandowski ◽  
S. Samardakiewicz ◽  
A. Basińska ◽  
...  
Keyword(s):  
Cell Wall ◽  
Metal Ions ◽  
Plant Cell ◽  
Plant Cell Wall
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