title: Biosynthesis of wine aroma: transcript profiles of hydroxymethylbutenyl diphosphate reductase, geranyl diphosphate synthase, and linalool/nerolidol synthase parallel monoterpenol glycoside accumulation in Gewürztraminer grapes.
abstract: In developing grapevine (Vitis vinifera L.) berries, precursor volatile organic compounds (PVOCs) are largely stored as glycosides which may be hydrolyzed to release VOCs during fruit ripening, wine making, or aging. VOCs can be further transformed by yeast metabolism. Together, these processes contribute to complexity of wine aromas. Floral and citrus odors of many white wine varietals are attributed to monoterpenes and monoterpene alcohols, while phenolic compounds, norisoprenoids, and other volatiles also play important roles in determining aroma. We present an analysis of PVOCs stored as glycosides in developing Gewürztraminer berries during the growing season. We optimized a method for PVOC analysis suitable for small amounts of Muscat grapevine berries and showed that the amount of PVOCs dramatically increased during and after véraison. Transcript profiling of the same berry samples underscored the involvement of terpenoid pathway genes in the accumulation of PVOCs. The onset of monoterpenol PVOC accumulation in developing grapes was correlated with an increase of transcript abundances of early terpenoid pathway enzymes. Transcripts encoding the methylerythritol phosphate pathway gene 4-hydroxy-3-methylbut-2-enyl diphosphate reductase, as well as geraniol diphosphate synthase, were up-regulated preceding and during the increase in monoterpenol PVOCs. Transcripts for linalool/nerolidol synthase increased in later véraison stages.
authors: Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, BC, V6T 1Z4, Canada. dianemm@interchange.ubc.ca
authors: Diane M
authors: DM
authors: Martin
authors: Angela
authors: A
authors: Chiang
authors: Steven T
authors: ST
authors: Lund
authors: Jörg
authors: J
authors: Bohlmann
mesh_terms: D019883:Alkyl and Aryl Transferases / Q000378:metabolism; D001483:Base Sequence; D051231:Farnesyltranstransferase / Q000737:chemistry* / Q000378:metabolism; D005638:Fruit / Q000201:enzymology* / Q000254:growth & development; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D006836:Hydro-Lyases / Q000737:chemistry*; D010088:Oxidoreductases / Q000737:chemistry* / Q000378:metabolism; D010937:Plant Growth Regulators / Q000378:metabolism; D012717:Sesquiterpenes / Q000378:metabolism; D014158:Transcription, Genetic; D027843:Vitis / Q000201:enzymology* / Q000235:genetics; D055549:Volatile Organic Compounds / Q000378:metabolism*; D014920:Wine
chemical_list: D010937:Plant Growth Regulators; D012717:Sesquiterpenes; D055549:Volatile Organic Compounds; D010088:Oxidoreductases; C579114:hydroxymethylbutenyl diphosphate reductase, Vitis vinifera; D019883:Alkyl and Aryl Transferases; C108877:terpene synthase; D051231:Farnesyltranstransferase; D006836:Hydro-Lyases; C092055:S-linalool synthase; C037055:nerolidol