title: Effect of calcium on strawberry fruit flavonoid pathway gene expression and anthocyanin accumulation.
abstract: Two diploid woodland strawberry (Fragaria vesca) inbred lines, Ruegen F7-4 (red fruit-bearing) and YW5AF7 (yellow fruit-bearing) were used to study the regulation of anthocyanin biosynthesis in fruit. Ruegen F7-4 fruit had similar total phenolics and anthocyanin contents to commercial octoploid (F. × ananassa) cultivar Seascape, while YW5AF7 exhibited relatively low total phenolics content and no anthocyanin accumulation. Foliar spray of CaCl2 boosted fruit total phenolics content, especially anthocyanins, by more than 20% in both Seascape and RF7-4. Expression levels of almost all the flavonoid pathway genes were comparable in Ruegen F7-4 and YW5AF7 green-stage fruit. However, at the turning and ripe stages, key anthocyanin structural genes, including flavanone 3-hydroxylase (F3H1), dihydroflavonol 4-reductase (DFR2), anthocyanidin synthase (ANS1), and UDP-glucosyltransferase (UGT1), were highly expressed in Ruegen F7-4 compared with YW5AF7 fruit. Calcium treatment further stimulated the expression of those genes in Ruegen F7-4 fruit. Anthocyanins isolated from petioles of YW5AF7 and Ruegen F-7 had the same HPLC-DAD profile, which differed from that of Ruegen F-7 fruit anthocyanins. All the anthocyanin structural genes except FvUGT1 were detected in petioles of YW5AF7 and Ruegen F-7. Taken together, these results indicate that the "yellow" gene in YW5AF7 is a fruit specific regulatory gene(s) for anthocyanin biosynthesis. Calcium can enhance accumulation of anthocyanins and total phenolics in fruit possibly via upregulation of anthocyanin structural genes. Our results also suggest that the anthocyanin biosynthesis machinery in petioles is different from that in fruit.
authors.affiliation: School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China; Food Quality Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service of U.S. Department of Agriculture (USDA-ARS), 10300 Baltimore Avenue, Beltsville, MD 20705, USA.
authors.forename: Wenping
authors.initials: W
authors.lastname: Xu
authors.affiliation: Food Quality Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service of U.S. Department of Agriculture (USDA-ARS), 10300 Baltimore Avenue, Beltsville, MD 20705, USA; College of Life Sciences, Guangxi Normal University, Guilin, Guangxi 541004, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Peng
authors.affiliation: Food Quality Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service of U.S. Department of Agriculture (USDA-ARS), 10300 Baltimore Avenue, Beltsville, MD 20705, USA. Electronic address: tianbao.yang@ars.usda.gov.
authors.forename: Tianbao
authors.initials: T
authors.lastname: Yang
authors.affiliation: Food Quality Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service of U.S. Department of Agriculture (USDA-ARS), 10300 Baltimore Avenue, Beltsville, MD 20705, USA.
authors.forename: Bruce
authors.initials: B
authors.lastname: Whitaker
authors.affiliation: Food Quality Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service of U.S. Department of Agriculture (USDA-ARS), 10300 Baltimore Avenue, Beltsville, MD 20705, USA; Hunan Agricultural Product Processing Institute, Hunan Academy of Agricultural Sciences, Changsha, Hunan 410125, China.
authors.forename: Luhong
authors.initials: L
authors.lastname: Huang
authors.affiliation: Food Composition and Methods Development Laboratory, Beltsville Human Nutrition Research Center, Agricultural Research Service of U.S. Department of Agriculture, Beltsville, MD 20705, USA.
authors.forename: Jianghao
authors.initials: J
authors.lastname: Sun
authors.affiliation: Food Composition and Methods Development Laboratory, Beltsville Human Nutrition Research Center, Agricultural Research Service of U.S. Department of Agriculture, Beltsville, MD 20705, USA.
authors.forename: Pei
authors.initials: P
authors.lastname: Chen
mesh_terms: D000872:Anthocyanins / Q000378:metabolism*; D002118:Calcium / Q000494:pharmacology*; D005419:Flavonoids / Q000378:metabolism*; D031985:Fragaria / Q000187:drug effects* / Q000378:metabolism*; D005638:Fruit / Q000187:drug effects* / Q000378:metabolism*
chemical_list: D000872:Anthocyanins; D005419:Flavonoids; D002118:Calcium
keywords: Anthocyanins; Calcium; Fruit color; Phenolics; Woodland strawberry