Biosynthesis of mono- and sesquiterpenes in strawberry fruits and foliage: 2H labeling studies.
The biosynthesis of the monoterpene (S)-linalool and the sesquiterpene trans-(S)-nerolidol in fruits of Fragaria x ananassa Duch. cv. Eros and Florence and of the monoterpene (-)-alpha-pinene in Fragaria vesca was investigated by in vivo feeding experiments with [5,5-2H2]mevalonic acid lactone (d2-MVL) and [5,5-2H2]-1-deoxy-d-xylulose (d2-DOX). The feeding experiments indicate that (S)-linalool and trans-(S)-nerolidol in Fragaria x ananassa Duch. and (-)-alpha-pinene in F. vesca are exclusively synthesized via the cytosolic mevalonic acid pathway without any contribution from the plastidial 1-deoxy-D-xylulose/2-C-methyl-D-erythritol 4-phosphate (DOXP/MEP) route. Inhibition experiments revealed that even the presence of mevastatin, an export of plastid-derived isopentyl diphosphate/dimethylallyl diphosphate, cannot be induced. However, the enantioselective analysis shows that in Fragaria x ananassa Duch. cv. Eros and Florence both linalool enantiomers are present and that only (S)-linalool is labeled after administration of d2-MVL. Therefore, the origin of (R)-linalool in these fruits remains unknown. Contrarily, in Fragaria x ananassa Duch. foliage (R)-linalool is the dominant enantiomer. Feeding experiments revealed an incorporation of d2-MVL and d2-DOX at equal rates exclusively into (S)-linalool. Only in F. vesca foliage, where (R)-linalool is present at high enantiomeric purity (ee > 90%), is a de novo biosynthesis of the (R)-enantiomer via the DOXP/MEP pathway detectable. These results demonstrate a complex intraplant variation of (R)- and (S)-linalool biosynthesis via the cytosolic and plastidial route.
Institut für Lebensmittelchemie, Johann Wolfgang Goethe-Universität, Marie-Curie-Strasse 9, D-60439 Frankfurt/Main, Germany.
Daniela
D
Hampel
Armin
A
Mosandl
Matthias
M
Wüst
D000080462:Acyclic Monoterpenes; D003903:Deuterium; D031985:Fragaria / Q000378:metabolism*; D005638:Fruit / Q000378:metabolism*; D008401:Gas Chromatography-Mass Spectrometry; D008798:Mevalonic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D039821:Monoterpenes / Q000378:metabolism*; D018515:Plant Leaves / Q000378:metabolism*; D012717:Sesquiterpenes / Q000378:metabolism*; D013237:Stereoisomerism; D014996:Xylulose / Q000031:analogs & derivatives / Q000378:metabolism
D000080462:Acyclic Monoterpenes; D039821:Monoterpenes; D012717:Sesquiterpenes; D014996:Xylulose; C029724:1-deoxy-2-pentulose; C015367:mevalonolactone; D003903:Deuterium; C018584:linalool; C037055:nerolidol; D008798:Mevalonic Acid