Eacute;tude ultrastructurale de l'interrelation hocirc;tendash;parasite entre le raisin et le champignonBotrytis cinerea: exemple de la pourriture noble en Sauternais

摘要

The hostndash;parasite relationship between Sauternes grapes andBotrytis cinereawas studied, on plants grown in the vineyards, with transmission and scanning electron microscopes. This study has revealed that the fungal attack is located on microfissures preexisting on the grapes. This attack does not appear before maturity, when the grapes' resistance to infection has decreased. The fungus grows then within the walls of skin cells while destroying pectic structures such as middle lamellae. After 4ndash;8 days, hyphae emerge out of the fruit surface and further develop into conidiophores. During these hostndash;parasite interactions, the biochemical activities ofB. cinerea, such as metabolizations and syntheses, deeply modify the wall of superficial grape cells. Finally, grapes lose their water and concentrate various substances. Such a development leads to the particular aromatic features of Sauternes wines.