University of Oulu

Karppinen, K., Lafferty, D.J., Albert, N.W., Mikkola, N., McGhie, T., Allan, A.C., Afzal, B.M., Häggman, H., Espley, R.V. and Jaakola, L. (2021), MYBA and MYBPA transcription factors co-regulate anthocyanin biosynthesis in blue-coloured berries. New Phytol, 232: 1350-1367.

MYBA and MYBPA transcription factors co-regulate anthocyanin biosynthesis in blue-coloured berries

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Author: Karppinen, Katja1; Lafferty, Declan J.2,3; Albert, Nick W.2;
Organizations: 1Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø 9037, Norway
2The New Zealand Institute for Plant and Food Research Ltd, Palmerston North 4410, New Zealand
3School of Biological Sciences, University of Auckland, Auckland 1142, New Zealand
4Department of Ecology and Genetics, University of Oulu, Oulu, 90014 Finland
5The New Zealand Institute for Plant and Food Research Ltd, Auckland 1025, New Zealand
6Department of Ecology and Genetics, University of Oulu, Oulu 90014, Finland
7Norwegian Institute of Bioeconomy Research (NIBIO), Ås 1431, Norway
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.7 MB)
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Language: English
Published: John Wiley & Sons, 2021
Publish Date: 2021-10-20


The regulatory network of R2R3 MYB transcription factors in anthocyanin biosynthesis is not fully understood in blue-coloured berries containing delphinidin compounds.

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.

VmMYBA1, VmMYBPA1.1 and VmMYBPA2.2 expression was elevated at berry ripening and by abscisic acid treatment. Additionally, VmMYBA1 and VmMYBPA1.1 expression was strongly downregulated in a white berry mutant. Complementation and transient overexpression assays confirmed VmMYBA1 and VmMYBA2 to induce anthocyanin accumulation. Promoter activation assays showed that VmMYBA1, VmMYBPA1.1 and VmMYBPA2.2 had similar activity towards dihydroflavonol 4-reductase (DFR) and anthocyanidin synthase (ANS), but differential regulation activity for UDP-glucose flavonoid 3-O-glucosyltransferase (UFGT) and flavonoid 3′5′-hydroxylase (F3′5′H) promoters. Silencing of VmMYBPA1.1 in berries led to the downregulation of key anthocyanin and delphinidin biosynthesis genes. Functional analyses of other MYBPA regulators, and a member of novel MYBPA3 subgroup, associated them with proanthocyanidin biosynthesis and F3′5′H expression.

The existence of 18 flavonoid-regulating MYBs indicated gene duplication, which may have enabled functional diversification among MYBA, MYBPA1 and MYBPA2 subgroups. Our results provide new insights into the intricate regulation of the complex anthocyanin profile found in blue-coloured berries involving regulation of both cyanidin and delphinidin branches.

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Series: New phytologist
ISSN: 0028-646X
ISSN-E: 1469-8137
ISSN-L: 0028-646X
Volume: 232
Issue: 3
Pages: 1350 - 1367
DOI: 10.1111/nph.17669
Type of Publication: A1 Journal article – refereed
Field of Science: 1182 Biochemistry, cell and molecular biology
Funding: This work was financially supported by NordPlant to LJ (NordForsk, grant no. 84597), and Niemi Foundation, Otto A. Malm Foundation and Osk. Huttunen Foundation to KK. NWA, DJL and RVE were funded by the New Zealand Ministry of Business, Innovation, and Employment contract C11X1704 ‘Filling the Void: boosting the nutritional content of NZ fruit’.
Copyright information: © 2021 The Authors. New Phytologist © 2021 New Phytologist Foundation. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.