AOBPreview originally published online on October 8, 2009
Annals of Botany 2009 104(7):1363-1372; doi:10.1093/aob/mcp254
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Temporal regulation of cell-wall pectin methylesterase and peroxidase isoforms in cadmium-treated flax hypocotyl
1 Laboratory Glyco-Mev, SCUEOR, IFRMP 23, University of Rouen, 76821 Mont Saint Aignan Cedex, France
2 Laboratory PBS-CNRS FRE3101, IFRMP 23, University of Rouen, 76821 Mont Saint Aignan Cedex, France
* For correspondence. E-mail florence.paynel{at}univ-rouen.fr
Received: 30 July 2009 Returned for revision: 27 August 2009 Accepted: 14 September 2009 Published electronically: 8 October 2009
Background and Aims: In hypocotyls of flax (Linum usitatissimum) cadmium-induced reorientation of growth (i.e. an increase in expansion and a decrease in elongation) coincides with marked changes in the methylesterification and cross-linking of homogalacturonans within various cell-wall (CW) domains. The aim of the present study was to examine the involvement of pectin methylesterase (PME) and peroxidase (PER) in this cadmium-induced CW remodelling.
Methods: CW proteins were extracted from hypocotyls of 10- and 18-d-old flax that had been treated or not treated with 0·5 mM Cd(NO3)2. PME and PER expression within these extracts was detected by LC/MS, by isoelectric focusing and enzyme activity assays. Transcript expression by RT-PCR of known flax PME and PER genes was also measured in corresponding samples.
Key Results: In cadmium-treated seedlings, PME activity increased as compared with controls, particularly at day 10. The increased activity of PME was accompanied by increased abundance of both a basic protein isoform (B2) and a particular transcript (Lupme5). In contrast, induction of PER activity by cadmium was highest at day 18. Among the four reported PER genes, Flxper1 and 3 increased in abundance in the presence of cadmium at day 18.
Conclusions: The temporal regulation of Lupme and Flxper genes and of their respective enzyme activities fits the previously reported cadmium-induced structural changes of homogalacturonans within the CWs. After PME-catalysed de-esterification of homogalacturonans, their cross-linking would depend on the activity of PERs interacting with calcium-dimerized blocks and reinforce the cell cohesion during the cadmium-induced swelling.
Key words: Cadmium, cell wall, homogalacturonan, Linum usitatissimum, pectin methylesterase, peroxidase
CiteULike 
Connotea 
Del.icio.us What's this?
Related articles in Ann Bot:
- ContentSnapshots
Ann Bot 2009 104: i.[Extract] [Full Text] - John Bryant takes a closer look at some of this month's Original Articles
- John Bryant
Ann Bot 2009 104: v.[Extract] [Full Text]
This article has been cited by other articles:
|
|
 |
|
  O. Douchiche, A. Driouich, and C. Morvan Spatial regulation of cell-wall structure in response to heavy metal stress: cadmium-induced alteration of the methyl-esterification pattern of homogalacturonans Ann. Bot., January 18, 2010; (2010) mcp306v1. [Abstract] [Full Text] [PDF]
|
|