INHIBITION OF ENZYME-SECRETION IN PLANT-PATHOGENS BY MEPANIPYRIM, A NOVEL FUNGICIDE

Mepanipyrim, N-(4-methyl-6-prop-1-ynylpyrimidin-2-yl) aniline, strongl y affected the infection process of Botrytis cinerea, a causative fung us of gray mold diseases. Mepanipyrim did not inhibit the activity of host-cell wall degrading enzymes (cutinase, pectinase, cellulase) of B . cinerea, which play an important role in the infection process. Howe ver, it prevented the secretion of these enzymes, leading to their int racellular accumulation. Secretory repression of host-cell wall degrad ing enzymes is assumed to cause depression of infectious activity and it is suggested to be an important mechanism in mepanipyrim disease co ntrol. Mepanipyrim also prevented the secretion of lipase, protease, a nd invertase of B. cinerea. The results suggest that mepanipyrim affec ts the intracellular transport process of secretory proteins. (C) 1994 Academic Press, Inc.