DIFFERENTIAL DEGRADATION OF APPLE CELL-WALLS IN-VITRO BY ENZYME EXTRACTS FROM BOTRYTIS-CINEREA AND GLOMERELLA-CINGULATA

Growth and associated glycosidase enzyme production and activity of Bo trytis cinerea and Glomerella cingulata were compared in vitro using a pple cell walls as a carbon source. In liquid culture, the growth of t he two pathogens was similar. Both fungi produced alpha-L-arabinosidas e but beta-D-galactosidase activity was higher in B. cinerea. In vitro degradation of apple cell walls by enzyme extracts from liquid cultur es of G. cingulata was greater than for B. cinerea. After 24h of incub ation, the G. cingulata extract solubilized 69% of the total cell wall neutral sugar and 78% of the total uronic acid, while the B. cinerea extract solubilized only 43% of the neutral sugar and 37% of the uroni c-acid-containing wall polymers. The neutral sugar composition of the residue remaining after degradation (the products left after the activ ity of the respective fungal enzymes) differed between the two fungi. (C) 1997 Elsevier Science Ltd.