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

Mepanipyrim, N-(4-methyl-6-prop-1-ynylpyrimidin-2-yl) aniline, strongly affected the infection process of Botrytis cinerea, a causative fungus 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. However, it prevented the secretion of these enzymes, leading to their intracellular accumulation. Secretory repression of host-cell wall degrading enzymes is assumed to cause depression of infectious activity and it is suggested to be an important mechanism in mepanipyrim disease control. Mepanipyrim also prevented the secretion of lipase, protease, and invertase of B. cinerea. The results suggest that mepanipyrim affects the intracellular transport process of secretory proteins. (C) 1994 Academic Press, Inc.