Submitted to: Food Chemistry
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/23/2009
Publication Date: 6/4/2009
Citation: Lee, J., Keller, K.E., Rennaker, C.D., Martin, R.R. 2009. Influence of Grapevine leafroll associated viruses (GLRaV-2 and -3) on the fruit composition of Oregon Vitis vinifera L. cv. Pinot noir: free amino acids, sugars, and organic acids. Food Chemistry. 117:99-105. Interpretive Summary: ‘Pinot noir’ is a major wine grape cultivar grown in Oregon. This paper reports on the impact of Grapevine leafroll associated viruses (GLRaVs) on compounds essential in fermentation like organic acids, sugars, and nitrogen-containing compounds (i.e. ammonium and free amino acids). Overall, virus status of the vines did not negatively alter organic acid, sugar, ammonium, free amino acids, and yeast assimilable nitrogen when GLRaV infected vines were compared to healthy vines with the following exception: Valine and methionine were lower in V. riparia rootstock / ‘Pinot noir’ clone 114 GLRaV infected samples compared to its healthy counterpart. Malic acid, organic acid, and glutamic acid were lower in self-rooted / ‘Pinot noir’ clone Pommard GLRaV-3 infected samples compared to its healthy pair.
Technical Abstract: Individual free amino acids, yeast assimilable amino acid (YAN) content, ammonium, organic acids, and simple sugars of berries from GLRaV-2 or GLRaV-3 infected vines were compared with paired vines free of these viruses. Samples were taken from two commercial vineyards during two growing seasons (2005 and 2006), with three different rootstock / scion combinations. GLRaV-2 infected vines did not differ significantly from their healthy counterparts in individual free amino acids, ammonium, or YAN content. GLRaV-3 infected vines were significantly lower in valine and methionine from V. riparia rootstock / ‘Pinot noir’ clone 114 (VY2a) samples, and lower in glutamic acid from self-rooted / ‘Pinot noir’ clone Pommard (VY2b) samples compared to their healthy counterparts. Samples from VY2b (self-rooted / ‘Pinot noir’ clone Pommard) infected vines had significantly lower levels of malic acid and total organic acid compared to its healthy counterpart. There were no significant differences between healthy and infected vines from all three rootstock / scion pairs in ammonium or free amino acids in samples taken during the weeks before ripening and at commercial harvest. This is the first study to report the influence of GLRaV-2 and -3 on ‘Pinot noir’ berries and nitrogen (N) compounds significant to fermentation. Individual free amino acids may be inferior to phenolic compounds as indicators of GLRaV infection status. No clear trends were observed on how GLRaV impacted N-containing compounds in ‘Pinot noir’ grapes.