Inhibition of phosphatidylcholine and chitin biosynthesis in Pyricularia oryzae, Botrytis fabae and Fusarium graminearum by edifenphos

Edifenphos concentrations of 7, 25 and 190 muM caused a 50% (ED50) decrease in colony growth of the fungi Pyricularia oryzae, Botrytis fabae and Fusarium graminearum respectively. The edifenphos concentration of 6, 95 and 350 muM caused a 50% decrease in the phosphatidylcholine (PC) context of biomass of Pyricularia oryzae, Botrytis fabae and Fusarium graminearum respectively, but membrane-bound chitin synthase preparation isolated from the three fungi were almost as responsive to edifenphos. The non-competitive inhibition of chitin synthase action directly inhibits chitin syntehsis, and indirectly inhibits it after PC biosynthesis.