| Abstract Detail
Secondary Metabolism - Afternoon Lewinsohn, Efraim [1], Davidovich-Rikanati, Rachel [1], Azulay, Yaniv [1], Bar, Einat [1], Zamir, Dani [2], Sitrit, Yaron [3], Tadmor, Yaakov [1], Pichersky, Eran [4]. Comparative genetics and metabolic engineering of lemon-scented monoterpenes to enhance tomato aroma. A systematic analysis of the carotenoid pigments and terpenoid aroma volatiles in tomato near isogenic lines that differ only in their color was performed. This led to the conclusion that carotenogenesis genes have pleiotropic effects on aroma traits. Comparative genetics evidence strongly suggests that many aroma volatiles, including pseudoionone and the lemon-scented monoterpene geranial, are derived from the breakdown of the red pigment lycopene in tomatoes. In contrast, geranial and neral (known collectively as citral), which impart a lemony flavor, are derived directly from geraniol and ultimately from geranyldiphosphate in lemon basil, a plant that does not accumulate lycopene. We have utilized the lemon-basil geraniol-synthase gene under the control of the tomato polygalacturonase promoter to divert the metabolic flow to lycopene into geraniol in tomato fruits. The transgenic fruits contained enhanced levels of geraniol. The monoterpene aldehydes geranial and neral were also present in appreciable amounts, probably due to the activity of an endogenous alcohol dehydrogenase activity. Additional geraniol-derived volatiles such as nerol, citronellol, citronellyl acetate, geranyl acetate, neric acid and geranic acids were also detected. Overall, transforming tomato with the geraniol synthase gene and directing its expression to the ripening fruit has resulted in profound effects on the aroma and overall flavor of the transgenic tomatoes at the expense of lycopene.
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1 - Newe Yaar Research Center, ARO, Vegetable crops and genetics, Ramat Yishay, 30095, Israel
2 - The Hebrew University of Jerusalem, The Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agriculture, Food and Environmental Qua, Rehovot, 76100, Israel
3 - USDA Agricultural Research Service, Horticulture, 1575 Linden Drive, Madison, WI, 53711, USA
4 - University of Michigan, Molecular, Cellular, and Developmental Biology, 830 N. University St., Ann Arbor, MI, 48109, USA
Keywords:
aroma
lycopene
monoterpene
geranial
flavor.
Session: Poster-68
Location: Ballroom CD/Monona Terrace
Date: Tuesday, July 25th, 2006
Time: 8:00 AM
Abstract ID:224 |
