Are pectins involved in cold acclimation and de-acclimation of winter oil-seed rape plants?
OBJECTIVE
The hypothesis was tested that pectin content and methylation degree participate in regulation of cell wall mechanical properties and in this way may affect tissue growth and freezing resistance over the course of plant cold acclimation and de-acclimation.


METHODS
Experiments were carried on the leaves of two double-haploid lines of winter oil-seed rape (Brassica napus subsp. oleifera), differing in winter survival and resistance to blackleg fungus (Leptosphaeria maculans).


RESULTS
Plant acclimation in the cold (2 degrees C) brought about retardation of leaf expansion, concomitant with development of freezing resistance. These effects were associated with the increases in leaf tensile stiffness, cell wall and pectin contents, pectin methylesterase (EC 3.1.1.11) activity and the low-methylated pectin content, independently of the genotype studied. However, the cold-induced modifications in the cell wall properties were more pronounced in the leaves of the more pathogen-resistant genotype. De-acclimation promoted leaf expansion and reversed most of the cold-induced effects, with the exception of pectin methylesterase activity.


CONCLUSIONS
The results show that the temperature-dependent modifications in pectin content and their methyl esterification degree correlate with changes in tensile strength of a leaf tissue, and in this way affect leaf expansion ability and its resistance to freezing and to fungus pathogens.
Solecka
Danuta
D
Department of Plant Molecular Biology, Institute of Experimental Plant Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland.
Zebrowski
Jacek
J
Kacperska
Alina
A
D000064:Acclimatization / Q000502:physiology*; D001203:Ascomycota / Q000502:physiology; D001696:Biomechanical Phenomena; D029688:Brassica napus / Q000378:metabolism* / Q000382:microbiology / Q000502:physiology; D002265:Carboxylic Ester Hydrolases / Q000378:metabolism; D049108:Cell Enlargement; D002473:Cell Wall / Q000502:physiology*; D004951:Esterification; D005615:Freezing; D005838:Genotype; D010368:Pectins / Q000378:metabolism*; D010935:Plant Diseases; D018515:Plant Leaves / Q000254:growth & development / Q000378:metabolism* / Q000502:physiology
D010368:Pectins; D002265:Carboxylic Ester Hydrolases; C022323:pectinesterase