Biosynthesis of 2-methyl-3-buten-2-ol emitted from needles of Pinus ponderosa via the non-mevalonate DOXP/MEP pathway of isoprenoid formation

The volatile hemiterpene 2-methyl-3-buten-2-ol (MBO) is emitted from the ne edles of several pine species from the Western United States and contribute s to ozone formation in the atmosphere. It is synthesised enzymatically fro m dimethylallyl diphosphate (DMAPP). We show here that needles of Pinus pon derosa Laws. incorporated [1-H-2(1)]-1-deoxy-D-xylulose (d-DOX) into the em itted MBO, but not D,L-[2-C-13]mevalonic acid lactone. Furthermore, MBO emi ssion was inhibited by fosmidomycin, a specific inhibitor of the second enz yme of the mevalonate-independent pathway of isopentenyl diphosphate and DM APP formation, i.e. the 1-deoxy-D-xylulose 5-phosphate/2-C-methyl-D-erythri tol 4-phosphate (DOXP/MEP) pathway. We thus prove that MBO emitted from nee dles of P. ponderosa is primarily formed via the DOYP/MEP pathway.