title: Changes in the abscisic acid levels and related gene expression during fruit development and ripening in bilberry (Vaccinium myrtillus L.).
abstract: Abscisic acid (ABA) is a natural plant hormone playing an important role in many physiological processes including fruit ripening and is also recently found to be potential for biomedical applications. This study was aimed to measure ABA levels and its biosynthesis in bilberry (Vaccinium myrtillus L.), which is one of the best sources of anthocyanins. Five ABA biosynthetic genes were isolated from bilberry and their expression profiles were studied in bilberry tissues, particularly during berry development. The level of ABA highly increased at the onset of bilberry fruit ripening, at the stage when expression of anthocyanin biosynthetic genes, chalcone synthase (VmCHS) and anthocyanidin synthase (VmANS), also increased. In fully ripe berries and leaves, ABA levels were lower but none was detected in bilberry stem or rhizome. The expression of 9-cis-epoxycarotenoid dioxygenase (VmNCED1) and putative neoxanthin synthase (VmNSY) was high in berry tissues and their expression increased markedly at the onset of berry ripening along with the accumulation of ABA. In contrast, the expression of zeaxanthin epoxidase (VmZEP), short-chain dehydrogenase/reductase (VmSDR/ABA2) and aldehyde oxidase (VmAO) were most highly associated with leaf tissues with no obvious relation to ABA content during berry development. The obtained results indicate that the ABA biosynthesis may play an important role in the regulation of ripening of non-climacteric bilberry fruits through transcriptional regulation of key ABA biosynthetic genes.
authors.affiliation: Department of Biology, University of Oulu, P.O. Box 3000, FIN-90014 Oulu, Finland. Electronic address: katja.karppinen@oulu.fi.
authors.forename: Katja
authors.initials: K
authors.lastname: Karppinen
authors.forename: Elina
authors.initials: E
authors.lastname: Hirvelä
authors.forename: Tiina
authors.initials: T
authors.lastname: Nevala
authors.forename: Nina
authors.initials: N
authors.lastname: Sipari
authors.forename: Marko
authors.initials: M
authors.lastname: Suokas
authors.forename: Laura
authors.initials: L
authors.lastname: Jaakola
mesh_terms: D000040:Abscisic Acid / Q000235:genetics* / Q000378:metabolism; D000217:Acyltransferases / Q000235:genetics / Q000378:metabolism; D042931:Aldehyde Oxidase / Q000235:genetics / Q000378:metabolism; D000872:Anthocyanins / Q000235:genetics* / Q000378:metabolism; D049308:Dioxygenases / Q000235:genetics / Q000378:metabolism; D005638:Fruit / Q000201:enzymology / Q000254:growth & development* / Q000378:metabolism; D015870:Gene Expression; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism; D010105:Oxygenases / Q000235:genetics / Q000378:metabolism; D018515:Plant Leaves / Q000201:enzymology / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D029800:Vaccinium myrtillus / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism
chemical_list: D000872:Anthocyanins; D010940:Plant Proteins; D000040:Abscisic Acid; D010088:Oxidoreductases; C097153:zeaxanthin epoxidase; D010105:Oxygenases; D049308:Dioxygenases; C109043:9-cis-epoxy-carotenoid dioxygenase; C118159:anthocyanidin synthase; D042931:Aldehyde Oxidase; C416521:neoxanthin synthase; D000217:Acyltransferases; C020141:flavanone synthetase
keywords: 9-Cis-epoxycarotenoid dioxygenase (NCED); Abscisic acid (ABA); Aldehyde oxidase (AO); Berry ripening; Biosynthesis; Ericaceae; European blueberry; Neoxanthin synthase (NSY); Vaccinium myrtillus