Farnesyl diphosphate synthase may determine the accumulation level of (−)-rotundone in 'Syrah' grapes

• H. Takase ^[2] ; K. Sasaki ^[2] ; G. Ikoma ^[2] ; H. Kobayash ^[3] ; H. Matsuo ^[3] ; S. Suzuki ^[1] ; R.Takata ^[2]
  1. [1] University of Yamanashi

     University of Yamanashi

     Japón

     
  2. [2] Kirin Company
  3. [3] Mercian Corporation

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• Localización: Vitis: Journal of Grapevine Research, ISSN 0042-7500, Vol. 55, Nº 3, 2016, págs. 99-106
• Idioma: inglés
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• Resumen

  • (−)-Rotundone is an oxygenated sesquiterpene responsible for the peppery aroma in grapes, wines, herbs, and spices, and it was first identified in 'Syrah' wine from Australia. In this study, we demonstrated the expression profiles of genes related to (−)-rotundone biosynthesis during the maturation of 'Syrah' grapes from two different vineyards, namely, the Iwaimura and Johnohira vineyards in Japan. The α-guaiene and (−)-rotundone accumulation levels in the grape exocarp from the Johnohira vineyard, which has a cool climat¬ic condition located at a high altitude, were extremely higher than those from the Iwaimura vineyard. Among the 2-C-methyl-D-erythritol-4-phosphate (MEP) path¬way genes, the transcript levels of 1-deoxy-D-xylu¬lose-5-phosphate synthase gene (DXS) in the grape ex¬ocarp from the Johnohira vineyard were higher than those from the Iwaimura vineyard after véraison. The expression levels of the mevalonate pathway genes, Vi¬tis vinifera terpene synthase gene (VvTPS24) and cy¬tochrome P450 gene (CYP71BE5) in the final step of (−)-rotundone biosynthesis were not significantly dif¬ferent between samples from the two vineyards during grape maturation. In contrast, the farnesyl diphos¬phate synthase gene (FPPS) expression level was con¬siderably higher in the grape exocarp from the Johno¬hira vineyard than in that from the Iwaimura vineyard. Consistent with these observations, FPPS was con¬stantly expressed at higher level in 'Syrah' grape exo¬carp compared with 'Merlot' grape which is a low-ro¬tundone cultivar. These findings suggest that FPPS may play a key role in determining the accumulation level of (−)-rotundone, which can provide abundant substrates for VvTPS24 catalysis to produce α-guaiene as a pre¬cursor of (−)-rotundone. In addition, among the MEP pathway genes, DXS may have a regulatory role for a precursor supply from the plastids to (−)-rotundone bi¬osynthesis.