| Title: | Manipulation of flavour and aroma compound sequestration and release using a glycosyltransferase with specificity for terpene alcohols |
| Author(s): | Yauk YK; Ged C; Wang MY; Matich AJ; Tessarotto L; Cooney JM; Chervin C; Atkinson RG; |
| Address: | "The New Zealand Institute for Plant & Food Research Limited (PFR), Private Bag 92169, Auckland, 1142, New Zealand" |
| ISSN/ISBN: | 1365-313X (Electronic) 0960-7412 (Linking) |
| Abstract: | "Glycosides are an important potential source of aroma and flavour compounds for release as volatiles in flowers and fruit. The production of glycosides is catalysed by UDP-glycosyltransferases (UGTs) that mediate the transfer of an activated nucleotide sugar to acceptor aglycones. A screen of UGTs expressed in kiwifruit (Actinidia deliciosa) identified the gene AdGT4 which was highly expressed in floral tissues and whose expression increased during fruit ripening. Recombinant AdGT4 enzyme glycosylated a range of terpenes and primary alcohols found as glycosides in ripe kiwifruit. Two of the enzyme's preferred alcohol aglycones, hexanol and (Z)-hex-3-enol, contribute strongly to the 'grassy-green' aroma notes of ripe kiwifruit and other fruit including tomato and olive. Transient over-expression of AdGT4 in tobacco leaves showed that enzyme was able to glycosylate geraniol and octan-3-ol in planta whilst transient expression of an RNAi construct in Actinidia eriantha fruit reduced accumulation of a range of terpene glycosides. Stable over-expression of AdGT4 in transgenic petunia resulted in increased sequestration of hexanol and other alcohols in the flowers. Transgenic tomato fruit stably over-expressing AdGT4 showed changes in both the sequestration and release of a range of alcohols including 3-methylbutanol, hexanol and geraniol. Sequestration occurred at all stages of fruit ripening. Ripe fruit sequestering high levels of glycosides were identified as having a less intense, earthier aroma in a sensory trial. These results demonstrate the importance of UGTs in sequestering key volatile compounds in planta and suggest a future approach to enhancing aromas and flavours in flowers and during fruit ripening" |
| Keywords: | "Actinidia/*enzymology/metabolism Alcohols/*metabolism Chromatography, Liquid Glycosyltransferases/*metabolism Kinetics Mass Spectrometry Molecular Sequence Data *Odorants Plants, Genetically Modified Substrate Specificity Terpenes/*metabolism Actinidia de;" |
| Notes: | "MedlineYauk, Yar-Khing Ged, Claire Wang, Mindy Y Matich, Adam J Tessarotto, Lydie Cooney, Janine M Chervin, Christian Atkinson, Ross G eng Research Support, Non-U.S. Gov't England 2014/08/05 Plant J. 2014 Oct; 80(2):317-30. doi: 10.1111/tpj.12634. Epub 2014 Sep 8" |
