title: Interaction of moderate UV-B exposure and temperature on the formation of structurally different flavonol glycosides and hydroxycinnamic acid derivatives in kale (Brassica oleracea var. sabellica).
abstract: Kale has a high number of structurally different flavonol glycosides and hydroxycinnamic acid derivatives. In this study we investigated the interaction of moderate UV-B radiation and temperature on these compounds. Kale plants were grown at daily mean temperatures of 5 or 15 °C and were exposed to five subsequent daily doses (each 0.25 kJ m(-2) d(-1)) of moderate UV-B radiation at 1 d intervals. Of 20 phenolic compounds, 11 were influenced by an interaction of UV-B radiation and temperature, e.g., monoacylated quercetin glycosides. Concomitantly, enhanced mRNA expression of flavonol 3'- hydroxylase showed an interaction of UV-B and temperature, highest at 0.75 kJ m(-2) and 15 °C. Kaempferol glycosides responded diversely and dependent on, e.g., the hydroxycinnamic acid residue. Compounds containing a catechol structure seem to be favored in the response to UV-B. Taken together, subsequent exposure to moderate UV-B radiation is a successful tool for enhancing the flavonoid profile of plants, and temperature should be considered.
authors.affiliation: Leibniz-Institute of Vegetable and Ornamental Crops Grossbeeren/Erfurt e.V. , Theodor-Echtermeyer-Weg 1, 14979 Grossbeeren, Germany.
authors.forename: Susanne
authors.initials: S
authors.lastname: Neugart
authors.forename: Michaela
authors.initials: M
authors.lastname: Fiol
authors.forename: Monika
authors.initials: M
authors.lastname: Schreiner
authors.forename: Sascha
authors.initials: S
authors.lastname: Rohn
authors.forename: Rita
authors.initials: R
authors.lastname: Zrenner
authors.forename: Lothar W
authors.initials: LW
authors.lastname: Kroh
authors.forename: Angelika
authors.initials: A
authors.lastname: Krumbein
mesh_terms: D001937:Brassica / Q000737:chemistry / Q000254:growth & development / Q000378:metabolism* / Q000528:radiation effects*; D003373:Coumaric Acids / Q000737:chemistry / Q000378:metabolism*; D044948:Flavonols / Q000737:chemistry / Q000378:metabolism*; D006027:Glycosides / Q000737:chemistry / Q000378:metabolism*; D015394:Molecular Structure; D010936:Plant Extracts / Q000737:chemistry / Q000378:metabolism*; D013696:Temperature; D014466:Ultraviolet Rays
chemical_list: D003373:Coumaric Acids; D044948:Flavonols; D006027:Glycosides; D010936:Plant Extracts
keywords: Brassica oleracea; UV-B; flavonoids; flavonol 3′-hydroxylase; flavonol glycosides; hydroxycinnamic acids