ISHS Acta Horticulturae 326: International Symposium on Pre- and Postharvest Physiology of Pome-fruit
ROLES OF PECTINS IN CELL WALLS |
| Authors: | P. Van Cutsem, J. Messiaen |
| Keywords: | pectin, cell wall, egg-box, elicitation, morphogenesis, ripening |
| Abstract:
Pectins of plant cell walls contain largely methylesterified homopolygalacturonic acid sequences. After deesterification by plant or pathogen pectin-methylesterases, these sequences can cross-link through calcium bridges to form "egg boxes", but they are also subject to degradation by polygalacturonases. The released fragments are elicitors of defence reactions and act on morphogenesis. The size-dependency of most responses is probably due to the fact that the activity of the fragments depends on their ability to adopt the "egg box" conformation. In a limited number of cases, steps of the signal transduction chain have been studied: cytosolic calcium increase, protein phosphorylation, DNA transcription … The involvement of pectic fragments in ripening is discussed from the point of view of wall softening. | |
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