Letter | Published:

The beet Y locus encodes an anthocyanin MYB-like protein that activates the betalain red pigment pathway

Nature Genetics volume 47, pages 9296 (2015) | Download Citation

Abstract

Nearly all flowering plants produce red/violet anthocyanin pigments. Caryophyllales is the only order containing families that replace anthocyanins with unrelated red and yellow betalain pigments1,2. Close biological correlation of pigmentation patterns suggested that betalains might be regulated by a conserved anthocyanin-regulating transcription factor complex consisting of a MYB, a bHLH and a WD repeat–containing protein (the MBW complex)3. Here we show that a previously uncharacterized anthocyanin MYB-like protein, Beta vulgaris MYB1 (BvMYB1), regulates the betalain pathway in beets. Silencing BvMYB1 downregulates betalain biosynthetic genes and pigmentation, and overexpressing BvMYB1 upregulates them. However, unlike anthocyanin MYBs, BvMYB1 will not interact with bHLH members of heterologous anthocyanin MBW complexes because of identified nonconserved residues. BvMYB1 resides at the historic beet pigment-patterning locus, Y, required for red-fleshed beets4. We show that Y and y express different levels of BvMYB1 transcripts. The co-option of a transcription factor regulating anthocyanin biosynthesis would be an important evolutionary event allowing betalains to largely functionally replace anthocyanins.

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NCBI Reference Sequence

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Acknowledgements

This work was supported by US Department of Agriculture grant 2008-35301-19032 and US National Science Foundation grant MCB-1122179. We thank E. Huq, S. Sung and V. Symonds for comments on the manuscript and discussion, I. Goldman (University of Wisconsin–Madison) for the W357B beet cultivar and K. Keller for pigment analysis.

Author information

Author notes

    • Gregory J Hatlestad
    •  & Neda A Akhavan

    These authors contributed equally to this work.

Affiliations

  1. Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas, USA.

    • Gregory J Hatlestad
    • , Neda A Akhavan
    • , Rasika M Sunnadeniya
    • , Lee Elam
    • , Scott Cargile
    • , Austin Hembd
    • , Antonio Gonzalez
    •  & Alan M Lloyd
  2. US Department of Agriculture-Agricultural Research Service, Sugarbeet and Bean Research Unit, Department of Crop and Soil Sciences, Michigan State University, East Lansing, Michigan, USA.

    • J Mitchell McGrath

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Contributions

G.J.H., N.A.A., R.M.S., L.E., S.C., A.H., A.G. and A.M.L. performed experiments. J.M.M. provided the BAC library, RIL mapping population and mapping expertise. G.J.H., N.A.A., R.M.S., J.M.M. and A.M.L. conceived of the project and contributed to manuscript writing and editing.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Alan M Lloyd.

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https://doi.org/10.1038/ng.3163

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