Expression analysis of anthocyanin biosynthetic genes in apple skin.pdf

Expression analysis of anthocyanin biosynthetic genes in apple skin: Effect of UV-B and temperature Benjamin Ewa Ubi a,b, Chikako Honda a,*, Hideo Bessho c, Satoru Kondo d, Masato Wada c, Shozo Kobayashi a, Takaya Moriguchi a aDepartment of Plant, Cell and Environment, National Institute of Fruit Tree Science, Tsukuba, Ibaraki 305-8605, Japan bDepartment of Crop Science, Faculty of Agriculture, University of Calabar, P.M.B.1115, Calabar, Nigeria cDepartment of Apple Research, National Institute of Fruit Tree Science, Morioka, Iwate 020-0123, Japan dGraduate School of Applied Biosciences, Hiroshima Prefectual University, Shobara, Hiroshima 727-0023, Japan Received 19 December 2004; received in revised form 17 October 2005; accepted 19 October 2005 Available online 15 November 2005 /locate/plantsci Plant Science 170 (2006) 571–578AbstractWe investigated the expression of the five anthocyanin biosynthetic genes, chalcone synthase (CHS), flavanone 3-hydroxylase (F3H), dihydroflavonol 4-reductase (DFR), anthocyanidin synthase (ANS), and UDP-glucose:flavonoid 3-O-glucosyltransferase (UFGluT) during ripening in five early ripening apple cultivars (‘Iwai’, ‘Sansa’, ‘Tsugaru’, ‘Homei-Tsugaru’, and ‘Akane’), as well as under UV-B and temperature treatments. Anthocyanin biosynthesis increased progressively during ripening, with the onset of rapid accumulation occurring at 107 days after full bloom (DAFB) in the four apple cultivars except ‘Iwai’. Generally, increase in the expression levels of all five biosynthetic genes in fruit skin coincided with increase of anthocyanin concentration. When the fruit was bagged about 1 month prior to commercial harvest to prevent anthocyanin biosynthesis, the expression of CHS, ANS and UFGluT was substantially depressed in fruit skin, whereas that of all five genes including CHS, ANS and UFGluT was enhanced by UV-B and low temperature treatments with the accumulation of anthocyanins. The accumulation level of the main anthocyanin pigment, cy