Labeling of major plant lipids and jasmonic acid using [1-(14C)] lauric acid.

A medium chain length fatty acid, [1-(14C)] lauric acid (12:0) was administered to the detached leaves of Artemisia and was incorporated into major lipids, including phospholipids and galactolipids. [1-(14C)]12:0 was elongated and desaturated into linolenic acid (18:3). In detached leaves of both Artemisia and Arabidopsis thaliana ecotype Columbia, radioactivity from [14C]18:3 was incorporated into jasmonic acid (JA) and methyl jasmonate (MJ). Higher amounts of [14C]JA were measured in Artemisia than Arabidopsis leaves. In Artemisia, [14C]JA was actively metabolized into [14C]MJ. Extracts prepared from the leaves of Artemisia, exhibited higher in vitro JA methyltransferase activity than those from Arabidopsis.