Location and biosynthesis of monoterpenyl fatty acyl esters in rose petals

The upper epidermal cell layer and epicuticular wax surface of Lady Seton rose petals are sites of biosynthesis and accumulation, respectively, of terpenyl fatty acyl esters based mainly on the monoterpene alcohol geraniol coupled primarily to fatty acids of carbon numbers 16-20. The esters account for 14-64% of the total monoterpenes present in the petal. The biosynthesis of the monoterpene component of the fatty acyl ester occurs via the mevalonic acid pathway in Lady Seton as well as in the hybrid tea rose Fragrant Cloud. In the latter flower the biosynthesis of geraniol was biosynthetically trans as was the formation of nerol and citronellol. Both geraniol and nerol were shown to be precursors of citronellol via an NADPH dependent reductase reaction.