Biochemical basis of selective disease controlling activity of mepanipyrim

Abstract

Mepanipyrim exhibited excellent disease control activity against Botrytis cinerea, but poor activity against Cochliobolus miyabeanus; however, the mycelial growth of C. miyabeanus was inhibited more strongly than that of B. cinerea. Therefore, disease control efficacy by mepanipyrim in vivo is not correlated with mycelial growth inhibition in vitro. While mepanipyrim prevented pectinase secretion in B. cinerea at 0.1-1 mg/ml, it did not interfere with secretion in C. miyabeanus, even at 100 mg/ml, indicating that its action is an important mechanism in disease control. Mepanipyrim affected the uptake of glucose and phenylalanine in the mycelia of both pathogens at higher doses. Thus, a secondary action of mepanipyrim may bring about mycelial growth inhibition in vitro.

Metabolism of a Fungicide Mepanipyrim by Soil Fungus Cunninghamella elegans ATCC36112

“…Several analogues (e.g., cyprodinil and Pyrimethanil) are also in agricultural use. Their mode of action is (a) inhibition of specific amino acid biosynthesis and/or (b) inhibition of protein sequestration ,, . The major mode of action of mepanipyrim is proposed to be the inhibition of pathogenicity-related protein secretion .…”

“…Their mode of action is (a) inhibition of specific amino acid biosynthesis and/or (b) inhibition of protein sequestration ,, . The major mode of action of mepanipyrim is proposed to be the inhibition of pathogenicity-related protein secretion . Mepanipyrim is quite a safe compound (acute oral LD 50 > 5000 mg kg −1 , rat) suggesting the least harmful effects on human or animal health, and several toxicological studies were reported − , .…”