AUTHOR=Smit Samuel Jacobus , Vivier Melané Alethea , Young Philip Richard 

TITLE=Linking Terpene Synthases to Sesquiterpene Metabolism in Grapevine Flowers

JOURNAL=Frontiers in Plant Science

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2019.00177

DOI=10.3389/fpls.2019.00177

ISSN=1664-462X

ABSTRACT=<p>Grapevine (<italic>Vitis vinifera</italic> L.) terpene synthases (VviTPS) are responsible for the biosynthesis of terpenic volatiles. Volatile profiling of nine commercial wine cultivars showed unique cultivar-specific variation in volatile terpenes emitted from grapevine flowers. The flower chemotypes of three divergent cultivars, Muscat of Alexandria, Sauvignon Blanc and Shiraz were subsequently investigated at two flower developmental stages (EL-18 and -26). The cultivars displayed unique flower sesquiterpene compositions that changed during flower organogenesis and the profiles were dominated by either (<italic>E</italic>)-β-farnesene, (<italic>E,E</italic>)-α-farnesene or (+)-valencene. <italic>In silico</italic> remapping of microarray probes to <italic>VviTPS</italic> gene models allowed for a meta-analysis of <italic>VviTPS</italic> expression patterns in the grape gene atlas to identify genes that could regulate terpene biosynthesis in flowers. Selected sesquiterpene synthase genes were isolated and functionally characterized in three cultivars. Genotypic differences that could be linked to the function of a targeted gene model resulted in the isolation of a novel and cultivar-specific single product sesquiterpene synthase from Muscat of Alexandria flowers (VvivMATPS10), synthesizing (<italic>E</italic>)-β-farnesene as its major volatile. Furthermore, we identified structural variations (SNPs, InDels and splice variations) in the characterized <italic>VviTPS</italic> genes that potentially impact enzyme function and/or volatile sesquiterpene production in a cultivar-specific manner.</p>