Cinnamate Metabolism in Ripening Fruit. Characterization of a UDP-Glucose:Cinnamate Glucosyltransferase from Strawberry

• Published in: Plant physiology (Bethesda) 2006-03, Vol.140 (3), p.1047-1058
• Main Authors: Lunkenbein, Stefan, Bellido, MariLuz, Aharoni, Asaph, Salentijn, Elma M.J, Kaldenhoff, Ralf, Coiner, Heather A, Muñoz-Blanco, Juan, Schwab, Wilfried
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Amino Acid Sequence; amino acid sequences; arabidopsis-thaliana; Auxins; Biochemical Processes and Macromolecular Structures; Biological and medical sciences; Cauliflower mosaic virus; Cell culture techniques; Cinnamates - chemistry; Cinnamates - metabolism; cinnamic acid; complementary DNA; Coumaric acids; cultivated strawberries; dna microarrays; DNA, Complementary - isolation & purification; Economic plant physiology; enzyme activity; enzyme kinetics; Enzymes; Esters; Esters - chemistry; Esters - metabolism; flavonoid 3-o-glucosyltransferase; Fragaria; Fragaria - enzymology; Fragaria - genetics; Fragaria - growth & development; Fragaria ananassa; fragaria x ananassa; Fructification, ripening. Postharvest physiology; Fruit - enzymology; Fruit - genetics; Fruit - growth & development; Fruits; fruits (plant anatomy); Fundamental and applied biological sciences. Psychology; gene expression regulation; Gene Expression Regulation, Developmental; Gene Expression Regulation, Plant; glucosyltransferases; Glucosyltransferases - genetics; Glucosyltransferases - metabolism; Glucosyltransferases - physiology; glycosyltransferases; Growth and development; heterologous expression; hexosyltransferases; Indoleacetic Acids - metabolism; Kinetics; Messenger RNA; Molecular Sequence Data; molecular-cloning; o-glucosyltransferase; Oxidative Stress; pectate lyase; Phylogeny; plant biochemistry; plant genetics; plant physiology; plant proteins; Plant Proteins - genetics; Plant Proteins - metabolism; Plants; Plants, Genetically Modified - metabolism; recombinant fusion proteins; Recombinant Fusion Proteins - metabolism; Ripening; Sequence Alignment; strawberries; substrate-specificity; Transgenic plants; UDP-glucose:cinnamate glucosyltransferase; Uridine Diphosphate Glucose - metabolism
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.105.074955

Strawberry (Fragaria x ananassa) fruit accumulate (hydroxy)cinnamoyl glucose (Glc) esters, which may serve as the biogenetic precursors of diverse secondary metabolites, such as the flavor constituents methyl cinnamate and ethyl cinnamate. Here, we report on the isolation of a cDNA encoding a UDP-Glc:cinnamate glucosyltransferase (Fragaria x ananassa glucosyltransferase 2 [FaGT2]) from ripe strawberry cv Elsanta that catalyzes the formation of 1-O-acyl-Glc esters of cinnamic acid, benzoic acid, and their derivatives in vitro. Quantitative real-time PCR analysis indicated that FaGT2 transcripts accumulate to high levels during strawberry fruit ripening and to lower levels in flowers. The levels in fruits positively correlated with the in planta concentration of cinnamoyl, p-coumaroyl, and caffeoyl Glc. In the leaf, high amounts of Glc esters were detected, but FaGT2 mRNA was not observed. The expression of FaGT2 is negatively regulated by auxin, induced by oxidative stress, and by hydroxycinnamic acids. Although FaGT2 glucosylates a number of aromatic acids in vitro, quantitative analysis in transgenic lines containing an antisense construct of FaGT2 under the control of the constitutive 35S cauliflower mosaic virus promoter demonstrated that the enzyme is only involved in the formation of cinnamoyl Glc and p-coumaroyl Glc during ripening.