Effect of calcium treatment prior toBotrytis cinereainfection on the changes in pectic composition of grape berry

The influence of calcium on the process of infection byBotrytis cinereawas studied following calcium infiltration of grape berries, using Sauvignon, a cultivar ofVitis viniferaknown to be susceptible toB. cinerea.Calcium pretreatment had no significant effect on infection rate. 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.