• Analysis of composition, morphology, and biosynthesis of cuticular wax in wild type bilberry (Vaccinium myrtillus L.) and its glossy mutant 

      Trivedi, Priyanka; Nguyen, Nga; Klavins, Linards; Kviesis, Jorens; Heinonen, Esa; Remes, Janne; Jokipii-Lukkari, Soile; Klavins, Maris; Karppinen, Katja; Jaakola, Laura; Häggman, Hely (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-03-09)
      In this study, cuticular wax load, its chemical composition, and biosynthesis, was studied during development of wild type (WT) bilberry fruit and its natural glossy type (GT) mutant. GT fruit cuticular wax load was comparable with WT fruits. In both, the proportion of triterpenoids decreased during fruit development concomitant with increasing proportions of total aliphatic compounds. In GT fruit, ...
    • Carotenoid metabolism during bilberry (Vaccinium myrtillus L.) fruit development under different light conditions is regulated by biosynthesis and degradation 

      Karppinen, Katja; Zoratti, Laura; Sarala, Marian; Carvalho, Elisabete; Hirsimäki, Jenni; Mentula, Helmi; Martens, Stefan; Häggman, Hely; Jaakola, Laura (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-04-21)
      <b>Background:</b> Carotenoids are important pigments and precursors for central signaling molecules associated in fruit development and ripening. Carotenoid metabolism has been studied especially in the climacteric tomato fruit but the content of carotenoids and the regulation of their metabolism have been shown to be highly variable between fruit species. Non-climacteric berries of the genus ...
    • Changes in the Proanthocyanidin Composition and Related Gene Expression in Bilberry (Vaccinium myrtillus L.) Tissues 

      Suvanto, Jussi; Karppinen, Katja; Riihinen, Kaisu; Jaakola, Laura; Salminen, Juha-Pekka (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-06-16)
      Berries of genus <i>Vaccinium</i> are rich in flavonoids and proanthocyanidins (PAs). We studied the PA composition and biosynthesis in bilberry (<i>Vaccinium myrtillus L.</i>) tissues and during fruit development. Soluble PAs, analyzed by UHPLC–MS/MS, were most abundant in stem and rhizome with the mean PA polymerization level varying between 4 and 6 in all tissues. Both A- and B-type PAs were ...
    • Compositional and morphological analyses of wax in northern wild berry species 

      Trivedi, Priyanka; Karppinen, Katja; Klavins, Linards; Kviesis, Jorens; Sundqvist, Petri; Nguyen, Nga; Heinonen, Esa; Klavins, Maris; Jaakola, Laura; Väänänen, Juha; Remes, Janne; Häggman, Hely (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-05-21)
      Aerial surfaces of plants are covered by a waxy cuticle protecting plants from excessive water loss and UV light. In the present study, composition and morphology of cuticular waxes of northern wild berry species bilberry (<i>Vaccinium myrtillus</i> L.), lingonberry (V. <i>vitis-idaea</i> L.), bog bilberry (V. <i>uliginosum</i> L.) and crowberry (<i>Empetrum nigrum</i> L.) were investigated. Scanning ...
    • Contrasting survival and physiological responses of sub-Arctic plant types to extreme winter warming and nitrogen 

      Bokhorst, Stef; Jaakola, Laura; Karppinen, Katja; Edvinsen, Guro Kristine; Mæhre, Hanne Kirsti; Bjerke, Jarle W. (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-11-21)
      Evergreen plants are more vulnerable than grasses and birch to snow and temperature variability in the sub-Arctic. Most Arctic climate impact studies focus on single factors, such as summer warming, while ecosystems are exposed to changes in all seasons. Through a combination of field and laboratory manipulations, we compared physiological and growth responses of dominant sub-Arctic plant types to ...
    • The Coordinated Action of MYB Activators and Repressors Controls Proanthocyanidin and Anthocyanin Biosynthesis in Vaccinium 

      Lafferty, Declan J.; Espley, Richard V.; Deng, Cecilia H; Dare, Andrew P.; Günther, Catrin S.; Jaakola, Laura; Karppinen, Katja; Boase, Murray R.; Wang, Lei; Luo, Henry; Allan, Andrew C.; Albert, Nick W. (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-06-24)
      Vaccinium berries are regarded as “superfoods” owing to their high concentrations of anthocyanins, flavonoid metabolites that provide pigmentation and positively affect human health. Anthocyanin localization differs between the fruit of cultivated highbush blueberry (V. corymbosum) and wild bilberry (V. myrtillus), with the latter having deep red flesh coloration. Analysis of comparative ...
    • Developmental and Environmental Regulation of Cuticular Wax Biosynthesis in Fleshy Fruits 

      Trivedi, Priyanka; Nguyen, Nga; Hykkerud, Anne Linn; Häggman, Hely; Martinussen, Inger; Jaakola, Laura; Karppinen, Katja (Journal article; Peer reviewed, 2019-04-19)
      The aerial parts of land plants are covered by a hydrophobic layer called cuticle that limits non-stomatal water loss and provides protection against external biotic and abiotic stresses. The cuticle is composed of polymer cutin and wax comprising a mixture of very-long-chain fatty acids and their derivatives, while also bioactive secondary metabolites such as triterpenoids are present. Fleshy ...
    • A dPCR Method for Quantitative Authentication of Wild Lingonberry (Vaccinium vitis-idaea) versus Cultivated American Cranberry (V. macrocarpon) 

      Karppinen, Katja; Avetisyan, Anna; Hykkerud, Anne Linn; Jaakola, Laura (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-05-19)
      Berries of the genus Vaccinium are highly valued health-beneficial superfoods, which are commonly subjected to adulteration and mixed with each other, or with other common berry species. A quantitative DNA-based method utilizing a chip-based digital polymerase chain reaction (dPCR) technique was developed for identifying and quantifying wild lingonberry (V. vitis-idaea) and cultivated American ...
    • Flavonoid biosynthesis is differentially altered in detached and attached ripening bilberries in response to spectral light quality 

      Samkumar, Amos; Karppinen, Katja; McGhie, Tony K.; Espley, Richard V.; Martinussen, Inger; Jaakola, Laura (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-07-22)
      Light spectral quality is known to affect flavonoid biosynthesis during fruit ripening. However, the response of fruits to different light conditions, when ripening autonomously from the parent plant (detached), has been less explored. In this study, we analyzed the effect of light quality on detached and naturally ripening (attached) non-climacteric wild bilberry (Vaccinium myrtillus L.) fruits ...
    • Insights into sugar metabolism during bilberry (Vaccinium myrtillus L.) fruit development 

      Samkumar, Amos; Karppinen, Katja; Dhakal, Binita; Martinussen, Inger; Jaakola, Laura (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-03-03)
      Bilberry fruit is regarded as one of the best natural sources of anthocyanins and iswidely explored for its health-beneficial compounds. Besides anthocyanins, one of themajor attributes that determine the berry quality is the accumulation of sugars thatprovide sweetness and flavor to ripening fruit. In this study, we have identified 25 sugarmetabolism-related genes in bilberry, including invertases ...
    • Light-controlled flavonoid biosynthesis in fruits 

      Zoratti, Laura; Karppinen, Katja; Escobar, Ana Luengo; Häggman, Hely; Jaakola, Laura (Journal article; Tidsskriftartikkel; Peer reviewed, 2014-10-09)
    • Metabolic and molecular analysis of white mutant Vaccinium berries show down-regulation of MYBPA1-type R2R3 MYB regulatory factor 

      Primetta, Anja; Karppinen, Katja; Riihinen, Kaisu; Jaakola, Laura (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-07-14)
      Main conclusion MYBPA1-type R2R3 MYB transcription factor shows down-regulation in white mutant berries of Vaccinium uliginosum deficient in anthocyanins but not proanthocyanidins suggesting a role in the regulation of anthocyanin biosynthesis. <p>Berries of the genus Vaccinium are among the best natural sources of flavonoids. In this study, the expression of structural and regulatory flavonoid ...
    • Molecular Cloning and Expression Analysis of hyp-1 Type PR-10 Family Genes in Hypericum perforatum 

      Karppinen, Katja; Derzso, Emese; Jaakola, Laura; Hohtola, Anja (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-04-21)
      Hypericum perforatum L. is an important medicinal plant for the treatment of depression. The plant contains bioactive hypericins that accumulate in dark glands present especially in reproductive parts of the plant. In this study, pathogenesis-related class 10 (PR-10) family genes were identified in H. perforatum, including three previously unidentified members with sequence homology to hyp-1, a ...
    • Monochromatic light increases anthocyanin content during fruit development in bilberry 

      Zoratti, Laura; Sarala, Marian; Carvalho, Elisabete; Karppinen, Katja; Martens, Stefan; Giongo, Lara; Häggman, Hely; Jaakola, Laura (Journal article; Tidsskriftartikkel; Peer reviewed, 2014)
    • MYBA and MYBPA transcription factors co-regulate anthocyanin biosynthesis in blue-coloured berries 

      Karppinen, Katja; Lafferty, Declan J.; Albert, Nick W.; Mikkola, Nelli; McGhie, Tony K.; Allan, Andrew C.; Afzal, Bilal M.; Häggman, Hely; Espley, Richard V.; Jaakola, Laura (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-08-05)
      <p>We used blue berries of bilberry (Vaccinium myrtillus) to comprehensively characterise flavonoid-regulating R2R3 MYBs, which revealed a new type of co-regulation in anthocyanin biosynthesis between members of MYBA-, MYBPA1- and MYBPA2-subgroups. <p>VmMYBA1, VmMYBPA1.1 and VmMYBPA2.2 expression was elevated at berry ripening and by abscisic acid treatment. Additionally, VmMYBA1 and VmMYBPA1.1 ...
    • On the developmental and environmental regulation of secondary metabolism in Vaccinium spp. berries 

      Karppinen, Katja; Zoratti, Laura; Nguyenquynh, Nga; Häggman, Hely; Jaakola, Laura (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-05-18)
      Secondary metabolites have important defense and signaling roles, and they contribute to the overall quality of developing and ripening fruits. Blueberries, bilberries, cranberries, and other Vaccinium berries are fleshy berry fruits recognized for the high levels of bioactive compounds, especially anthocyanin pigments. Besides anthocyanins and other products of the phenylpropanoid and flavonoid ...
    • Recognition of candidate transcription factors related to bilberry fruit ripening by de novo transcriptome and qRT-PCR analyses 

      Nguyen, Nga; Suokas, Marko; Karppinen, Katja; Vuosku, Jaana; Jaakola, Laura; Häggman, Hely (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-07-02)
      Bilberry (<i>Vaccinium myrtillus</i> L.) fruits are an excellent natural resource for human diet because of their special flavor, taste and nutritional value as well as medical properties. Bilberries are recognized for their high anthocyanin content and many of the genes involved in the anthocyanin biosynthesis have been characterized. So far, neither genomic nor RNA-seq data have been available for ...
    • Red and blue light treatments of ripening bilberry fruits reveal differences in signalling through abscisic acid-regulated anthocyanin biosynthesis 

      Samkumar, Amos; Jones, Dan; Karppinen, Katja; Dare, Andrew P.; Sipari, Nina; Espley, Richard V.; Martinussen, Inger; Jaakola, Laura (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-08-01)
      The biosynthesis of anthocyanins has been shown to be influenced by light quality. However, the molecular mechanisms underlying the light-mediated regulation of fruit anthocyanin biosynthesis are not well understood. In this study, we analysed the effects of supplemental red and blue light on the anthocyanin biosynthesis in non-climacteric bilberry (<i>Vaccinium myrtillus</i> L.). After 6 days of ...
    • Temperature has a major effect on the cuticular wax composition of bilberry (Vaccinium myrtillus L.) fruit 

      Trivedi, Priyanka; Klavins, Linards; Hykkerud, Anne Linn; Kviesis, Jorens; Elferts, Didzis; Martinussen, Inger; Klavins, Maris; Karppinen, Katja; Häggman, Hely; Jaakola, Laura (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-09-20)
      Cuticle is the first layer protecting plants against external biotic and abiotic factors and is responsive to climatic factors as well as determined by genetic adaptations. In this study, the chemical composition of bilberry fruit cuticular wax was investigated through a latitudinal gradient from Latvia (56◦N 24◦E) through Finland (65◦N 25◦E) to northern Norway (69◦N 18◦E) in two seasons 2018 ...
    • Trace element concentration and stable isotope ratio analysis in blueberries and bilberries: A tool for quality and authenticity control 

      Klavins, Linards; Maaga, Inessa; Bertins, Maris; Hykkerud, Anne Linn; Karppinen, Katja; Bobinas, Česlovas; Nguyen, Nga; Salo, Heikki M.; Salminen, Henriikka; Stankevica, Karina; Klavins, Maris (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-03-09)
      Vaccinium genus berries—wild bilberries (Vaccinium myrtillus L.) and cultivated highbush blueberries (Vaccinium corymbosum L.)—are consumed worldwide, and their consumption has a trend of stable increase. Thus, considering their wide use in ethnomedicine, for juice and jam production, as functional food, as well as their use in preparations of extracts which have application potential in pharmaceutical ...