Lipid composition of Botrytis cinerea and inhibition of its radiolabelling by the fungicide iprodione

• Botrytis cinerea is an important plant pathogen that causes grey mould in over 200 hosts. It is often controlled by dicarboximides, which have various proposed mechanisms of action, including effects on lipids. Here we have examined the effect of one dicarboximide, iprodione, on lipid metabolism. • B. cinerea, cultured in malt extract media, was challenged with iprodione and its lipids extracted, separated by TLC, and analysed by GLC. Lipid metabolism was followed using [1-¹⁴ C]acetate. • Triacylglycerol was the major nonpolar and phosphatidylcholine the main polar lipid in B. cinerea. Linoleate, followed by α-linolenate, were the major fatty acids and most lipid classes had compositions broadly similar to the total fatty acid pattern. Iprodione, at concentrations causing a cessation of growth (5 µM) caused a decrease in polar lipid but not total nonpolar lipid labelling. Within the nonpolar lipids, DAG was better labelled. • The data show that iprodione had a selective effect on lipid metabolism. The altered pattern of labelling suggested that choline (ethanolamine) phosphotransferase would be worth investigating as a primary site of action.

Botrytis cinerea; cholinephosphotransferase; dicarboximide fungicide; iprodione; lipids.