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Publications

NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.

2023

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Abstract

Vaccinium berries include several economically important cultivated and wild species such as blueberries, cranberries, bilberries and lingonberries. These species are recognized for the various health beneficial properties, which are generally linked to the high yields and the complex profile of flavonoids in the berries, including anthocyanin, proanthocyanidin, and flavonol classes of flavonoids. Anthocyanins are one of the main pigments in plants contributing to the characteristic reddish to bluish colours in flowers and fruits. Most important anthocyanins are glucosides of six common aglycons: cyanidins, delphinidins, pelargonidins, petunidins, peonidins and malvidins. Of these, delphinidin branch anthocyanins, namely delphinidins, petunidins, and malvidins are responsible of bluish colours in blue Vaccinium berries. The biosynthesis of anthocyanins has been intensively studied, and the structural enzyme genes responsible of the specific steps of the pathway have been characterised also in diverse Vaccinium species. For the delphinidin branch, flavanone 3’5’ hydroxylase (F3’5’H) is the key enzyme for the branching point towards bluish anthocyanins. Our recent results both from controlled and field experiments have revealed new information on the key regulators controlling the different branches of the anthocyanin biosynthesis in blue-coloured berries. Transcriptome analyses combined with metabolite results have identified signaling routes leading to increase in delphinidin branch anthocyanins. Our results show that the anthocyanin composition in blue Vaccinium berries could be modified by specific environmental factors.

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Abstract

Wild berries are abundant in health-beneficial bioactive compounds, such as flavonoids, carotenoids, vitamins, and polyphenolic compounds, which accumulate during the fruit ripening process. Interestingly, wild Vaccinium berries from northern latitudes are found to contain more bioactive compounds compared to southern clones. The genetic adaptation is most likely favoured by environmental conditions, such as extended day length, cool temperatures and light spectral qualities. The molecular mechanisms underlying the regulation of secondary metabolite biosynthesis in response to light quality have been scarcely explored in Vaccinium berries. The present study is focused on gaining knowledge on the regulatory process under supplemental red and blue light in non-climacteric wild bilberry (Vaccinium myrtillus L.). Controlled experiments were carried out in phytotrons with local Norwegian ecotypes of bilberry, which were subjected from early to late ripening stages to continuous exposure to specific red and blue wavelengths provided by light-emitting diodes (LEDs). Berry samples from mid-ripening stage were utilized for the gene expression analysis based on RNA-seq transcriptome profiling. Our recent analyses from the transcriptome data set have shown that light wavelengths induce the anthocyanin biosynthetic genes, resulting in higher delphinidin accumulation in ripe bilberries. The enhanced secondary metabolic pathways influenced by such light qualities and the differential expression patterns in light-reaction centers as observed in various subunit complexes of photosystem I and II in the photosynthetic apparatus are briefly discussed in this study. This is crucial in order to study how plants acclimatize to modified light environment in terms of photosynthesis. The differences in expression of hormone signal transduction pathway genes were also discussed. The results will contribute to a better understanding of the light-mediated biosynthesis of phytochemicals in Vaccinium berries.