Aminoacids and Flavonoids Profiling in Tempranillo Berries Can Be Modulated by the Arbuscular Mycorrhizal Fungi

Abstract

(1) Background: Vitis vinifera L. cv. Tempranillo is cultivated over the world for its wine of high quality. The association of Tempranillo with arbuscular mycorrhizal fungi (AMF) induced the accumulation of phenolics and carotenoids in leaves, affected the metabolism of abscisic acid (ABA) during berry ripening, and modulated some characteristics and quality aspects of grapes. The objective of this study was to elucidate if AMF influenced the profiles and the content of primary and secondary metabolites determinants for berry quality in Tempranillo. (2) Methods: Fruit-bearing cuttings inoculated with AMF or uninoculated were cultivated under controlled conditions. (3) Results: Mycorrhizal symbiosis modified the profile of metabolites in Tempranillo berries, especially those of the primary compounds. The levels of glucose and amino acids clearly increased in berries of mycorrhized Tempranillo grapevines, including those of the aromatic precursor amino acids. However, mycorrhizal inoculation barely influenced the total amount and the profiles of anthocyanins and flavonols in berries. (4) Conclusions: Mycorrhizal inoculation of Tempranillo grapevines may be an alternative to the exogenous application of nitrogen compounds in order to enhance the contents of amino acids in grapes, which may affect the aromatic characteristics of wines.

Keywords: Aromatic precursors; Vitis vinifera; berry skin metabolites; mycorrhizal symbiosis; phenolic compounds; soluble sugars.

Figure 1

Concentration of aromatic precursors in berry skins of Tempranillo non-inoculated (a) or inoculated (b) with arbuscular mycorrhizal fungi. Values represent means (n=3). One-way ANOVA was performed to evaluate the effect of mycorrhizal inoculation. Means followed by different letter indicate that values are significantly different (P > 0.05). DW, dry weight.

Figure 2

HPLC chromatograms of amino acid profile from berry skins of Tempranillo non-inoculated (a) or inoculated (b) with arbuscular mycorrhizal fungi. Asp: Aspartic acid; Glu: Glutamic acid; Asn: Asparagine; Ser: Serine; Gly: Glycine; Gln: Glutamine; His: Histidine; Arg: Arginine; Thr: Threonine; Ala: Alanine; GABA: γ-aminobutyric acid; Pro: Proline; Tyr: Tyrosine; Cys: Cysteine; Val: Valine; Met: Methionine; Ileu: Isoleucine; Lys: Lysine; Leu: Leucine; Phe: Phenylalanine. Excitation and emission wavelengths were 250 nm and 395 nm, respectively.

Figure 3

HPLC chromatograms showing the anthocyanin profile from berry skins of Tempranillo non-inoculated (a) or inoculated (b) with arbuscular mycorrhizal fungi. Dp-3-glc: Delphinidin-3-glucoside; Cy-3-glc: Cyanidin-3-glucoside; Pt-3-glc: Petunidin3-glucoside; Pn-3-glc: Peonidin-3-glucoside; Mv-3-glc: Malvidin-3-glucoside; Dp-3-glc-ac: Delphinidin-3-acetyl-glucoside; Cy-3-glc-ac: Cyanidin-3-acetyl-glucosides; Pt-3-glc-ac: Petunidin-3-acetyl-glucosides; Pn-3-glc-ac: Peonidin-3-acetyl-glucosides; Dp-3-glc-cou: Delphinidin-3 p-coumaroyl-glucoside; Mv-3-glc-ac: Malvidin-3-acetyl-glucosides; Cy-3-glc-cou: Cyanidin-3 p-coumaroyl-glucoside; cis Pn-3-glc-cou: cis-Peonidin-3 p-coumaroyl-glucoside; Pt-3-glc-cou: Petunidin-3 p-coumaroyl-glucoside; cis-Mv-3-glc-cou: cis-Malvidin-3 p-coumaroyl-glucoside; Pn-3-glc-cou: Peonidin-3 p-coumaroyl-glucoside; Mv-3-glc-cou: Malvidin-3 p-coumaroyl-glucoside. A detection wavelength of 520 nm was used.

Figure 4

HPLC chromatograms showing the flavonol profile from berry skins of Tempranillo non-inoculated (a) or inoculated (b) with arbuscular mycorrhizal fungi. Myricetin-3-glc: Myricetin-3-O-glucoside; Querc-3-glc: Quercetin-3-O-glucoside; Laricitrin-3-glc: Laricitrin-3-O-glucoside; Kaempferol-3-glc: Kaempferol-3-O-glucoside; Isorhamnetin-3-glc: Isorhamnetin-3-O-glucoside. A detection wavelength of 360 nm was used.