The biosynthesis and regulation of biosynthesis of Concord grape fruit esters, including ‘foxy’ methylanthranilate

Abstract

SummaryThe biosynthesis of methyl anthranilate, the volatile compound responsible for the distinctive 'foxy' aroma and flavor of the Washington Concord grape (Vitis labrusca), involves an alcohol acyltransferase that catalyzes the formation of methyl anthranilate from anthraniloyl-coenzyme A (CoA) and methanol. Although methanol is a poor substrate in comparison with the co-substrate, high levels of this acyltransferase (0.5% of the total protein) combined with relatively high levels of this alcohol make this reaction possible in grapes. This 449 amino acid protein belongs to the BAHD family of acyltransferases, having 58% identity with the benzoyl CoA:benzyl alcohol benzoyl transferase from Clarkia. Both native and recombinant enzymes can use a broad range of acyl-CoAs and alcohols as substrates. The ability of Concord grape alcohol acyltransferase to accept a range of different CoA esters and alcohols suggests this to be a versatile ester-forming enzyme, similar to those of other fruits that than can produce a range of fruit esters based on the supply of appropriate substrates. Expression is coordinately regulated, with transcript, protein and enzyme activities coinciding with the accumulation of methyl anthranilate that occurs after the initiation of berry ripening. The majority of acyltransferase protein in grape tissues is localized to the outer fruit mesocarp, a result consistent with the fact that methyl anthranilate is released to the external environment throughout the ripening process. Wine grapes (Vitis vinifera) that accumulate neither anthranilate nor methyl anthranilate do not express this enzyme activity nor do they accumulate this protein.

Origins of Grape and Wine Aroma. Part 1. Chemical Components and Viticultural Impacts

“…One of the more interesting grape-derived volatile phenylpropanoids is methyl anthranilate, which is considered to be responsible for the distinctive "foxy" aroma and flavor of the Washington Concord grape (Vitis labrusca) (Wang and De Luca 2005) and may also contribute to the aroma of Pinot noir (Moio and Etievant 1995). First identified in grape juice in 1921 (Power and Chesnut 1921), methyl anthranilate has become a major compound used in the fragrance of perfumes and cosmetics and it is the chief grape flavor compound in food, used extensively in the flavoring of soft drinks and powder drinks (Wang and De Luca 2005).…”

Herbivore-Induced SABATH Methyltransferases of Maize That Methylate Anthranilic Acid Using S-Adenosyl-l-Methionine

“…Our understanding of methyl anthranilate biosynthesis in plants is very limited. The only enzyme that has been described to be involved in methyl anthranilate synthesis is the anthraniloylCoA:methanol acyltransferase in Washington Concord grape (Vitis vinifera; Wang and De Luca, 2005). In contrast, the biosynthesis of methyl salicylate has been well studied in several plant species, such as Clarkia brewerii (Ross et al, 1999), Arabidopsis (Arabidopsis thaliana; Chen et al, 2003), and rice (Oryza sativa; Xu et al, 2006;Koo et al, 2007;Zhao et al, 2010).…”

<i>n</i>-Propyl dihydrojasmonates influence ethylene signal transduction in infected apple fruit by <i>Botrytis cinerea</i>

“…In the β-oxidation pathway, the fatty acid is catabolized to alcohols and acyl co-enzyme A (acyl-CoA), then the acyl-CoA is resolved by a series of enzymes such as lipoxygenase (LOX), hydroperoxide lyase (HPL), pyruvate decarboxylase (PDC), alcohol dehydrogenase (ADH), and alcohol acyltransferase (AAT) (Defilippi et al, 2005;Wang and Luca, 2005). Ethylene was shown to play a role in the production of compounds during ripening (Johnston et al, 2009).…”