Effect of calcium treatment prior to Botrytis cinerea infection on the changes in pectic composition of grape berry

The influence of calcium on the process of infection by Botrytis cinerea was studied following calcium infiltration of grape berries, using Sauvignon, a cultivar of Vitis vinifera known to be susceptible to B. cinerea. Calcium pretreatment had no significant effect on infection rare. Analysis of pectic fractions of rotten berries showed that total amount of pectins decreased during infection. The proportion of water and chelator soluble pectins increased over the same time period. These changes in pectic fractions were less pronounced when grape berries were calcium infiltrated prior to infection. Demethylated pectins produced by the fungal pathogen are probably protected by a rapid calcium chelation. (C) 1997 Academic Press Limited.