title: Characterization of a multifunctional caffeoyl-CoA O-methyltransferase activated in grape berries upon drought stress.
abstract: Drought stress affects anthocyanin accumulation and modification in vegetative and reproductive plant tissues. Anthocyanins are the most abundant flavonoids in grape (Vitis vinifera L.) coloured berry genotypes and are essential markers of grape winemaking quality. They are mostly mono- and di-methylated, such modifications increase their stability and improve berry quality for winemaking. Anthocyanin methylation in grape berries is induced by drought stress. A few caffeoyl-CoA O-methyltransferases (CCoAOMTs) active on anthocyanins have been described in grape. However, no drought-activated O-methyltransferases have been described in grape berries yet. In this study, we characterized VvCCoAOMT, a grapevine gene known to induce methylation of CoA esters in cultured grape cells. Transcript accumulation of VvCCoAOMT was detected in berry skins, and increased during berry ripening on the plant, and in cultured berries treated with ABA, concomitantly with accumulation of methylated anthocyanins, suggesting that anthocyanins may be substrates of this enzyme. Contrary as previously observed in cell cultures, biotic stress (Botrytis cinerea inoculation) did not affect VvCCoAOMT gene expression in leaves or berries, while drought stress increased VvCCoAOMT transcript in berries. The recombinant VvCCoAOMT protein showed in vitro methylating activity on cyanidin 3-O-glucoside. We conclude that VvCCoAOMT is a multifunctional O-methyltransferase that may contribute to anthocyanin methylation activity in grape berries, in particular under drought stress conditions.
authors: University of Turin, Dept. Agricultural, Forestry and Food Sciences, Largo Paolo Braccini 2, 10095 Grugliasco, TO, Italy.
authors: Debora
authors: D
authors: Giordano
authors: University of Turin, Dept. Agricultural, Forestry and Food Sciences, Largo Paolo Braccini 2, 10095 Grugliasco, TO, Italy.
authors: Sofia
authors: S
authors: Provenzano
authors: University of Turin, Dept. Agricultural, Forestry and Food Sciences, Largo Paolo Braccini 2, 10095 Grugliasco, TO, Italy.
authors: Alessandra
authors: A
authors: Ferrandino
authors: University of Turin, Dept. Agricultural, Forestry and Food Sciences, Largo Paolo Braccini 2, 10095 Grugliasco, TO, Italy.
authors: Marco
authors: M
authors: Vitali
authors: University of Turin, Dept. Agricultural, Forestry and Food Sciences, Largo Paolo Braccini 2, 10095 Grugliasco, TO, Italy.
authors: Chiara
authors: C
authors: Pagliarani
authors: University of Turin, Dept. Agricultural, Forestry and Food Sciences, Largo Paolo Braccini 2, 10095 Grugliasco, TO, Italy.
authors: Federica
authors: F
authors: Roman
authors: University of Turin, Dept. Agricultural, Forestry and Food Sciences, Largo Paolo Braccini 2, 10095 Grugliasco, TO, Italy.
authors: Francesca
authors: F
authors: Cardinale
authors: The University of British Columbia Wine Research Centre, 2205 East Mall, Vancouver, BC V6T 1Z4, Canada.
authors: Simone D
authors: SD
authors: Castellarin
authors: University of Turin, Dept. Agricultural, Forestry and Food Sciences, Largo Paolo Braccini 2, 10095 Grugliasco, TO, Italy. Electronic address: andrea.schubert@unito.it.
authors: Andrea
authors: A
authors: Schubert
mesh_terms: D000872:Anthocyanins / Q000235:genetics / Q000378:metabolism; D005638:Fruit / Q000201:enzymology* / Q000235:genetics; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D008745:Methylation; D008780:Methyltransferases / Q000096:biosynthesis* / Q000235:genetics; D010940:Plant Proteins / Q000096:biosynthesis* / Q000235:genetics; D013312:Stress, Physiological; D027843:Vitis / Q000201:enzymology* / Q000235:genetics
chemical_list: D000872:Anthocyanins; D010940:Plant Proteins; D008780:Methyltransferases; C059825:caffeoyl-CoA O-methyltransferase
keywords: Anthocyanins; Berry ripening; Botrytis cinerea; Drought stress; Grapevine; O-methyltransferases