Brown-midrib maize (bm1) – a mutation affecting the cinnamyl alcohol dehydrogenase gene

Authors

  • Claire Halpin,

    1. Zeneca Seeds, Jealott’s Hill Research Station, Bracknell, Berks RG12 6EY, UK,, INRA CRA, Biochim, Macromol Vegetales,F-51686 Reims, France,, IACR-Long Ashton Research Station, Bristol BS18 9AF, UK, and, Department of Biological Sciences, University of Dundee, Dundee DD1 4HN, UK
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  • Karen Holt,

    1. Zeneca Seeds, Jealott’s Hill Research Station, Bracknell, Berks RG12 6EY, UK,, INRA CRA, Biochim, Macromol Vegetales,F-51686 Reims, France,, IACR-Long Ashton Research Station, Bristol BS18 9AF, UK, and, Department of Biological Sciences, University of Dundee, Dundee DD1 4HN, UK
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  • Jan Chojecki,

    1. Zeneca Seeds, Jealott’s Hill Research Station, Bracknell, Berks RG12 6EY, UK,, INRA CRA, Biochim, Macromol Vegetales,F-51686 Reims, France,, IACR-Long Ashton Research Station, Bristol BS18 9AF, UK, and, Department of Biological Sciences, University of Dundee, Dundee DD1 4HN, UK
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  • Duncan Oliver,

    1. Zeneca Seeds, Jealott’s Hill Research Station, Bracknell, Berks RG12 6EY, UK,, INRA CRA, Biochim, Macromol Vegetales,F-51686 Reims, France,, IACR-Long Ashton Research Station, Bristol BS18 9AF, UK, and, Department of Biological Sciences, University of Dundee, Dundee DD1 4HN, UK
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  • Brigitte Chabbert,

    1. Zeneca Seeds, Jealott’s Hill Research Station, Bracknell, Berks RG12 6EY, UK,, INRA CRA, Biochim, Macromol Vegetales,F-51686 Reims, France,, IACR-Long Ashton Research Station, Bristol BS18 9AF, UK, and, Department of Biological Sciences, University of Dundee, Dundee DD1 4HN, UK
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  • Bernard Monties,

    1. Zeneca Seeds, Jealott’s Hill Research Station, Bracknell, Berks RG12 6EY, UK,, INRA CRA, Biochim, Macromol Vegetales,F-51686 Reims, France,, IACR-Long Ashton Research Station, Bristol BS18 9AF, UK, and, Department of Biological Sciences, University of Dundee, Dundee DD1 4HN, UK
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  • Keith Edwards,

    1. Zeneca Seeds, Jealott’s Hill Research Station, Bracknell, Berks RG12 6EY, UK,, INRA CRA, Biochim, Macromol Vegetales,F-51686 Reims, France,, IACR-Long Ashton Research Station, Bristol BS18 9AF, UK, and, Department of Biological Sciences, University of Dundee, Dundee DD1 4HN, UK
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  • Abdellah Barakate,

    1. Zeneca Seeds, Jealott’s Hill Research Station, Bracknell, Berks RG12 6EY, UK,, INRA CRA, Biochim, Macromol Vegetales,F-51686 Reims, France,, IACR-Long Ashton Research Station, Bristol BS18 9AF, UK, and, Department of Biological Sciences, University of Dundee, Dundee DD1 4HN, UK
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  • Geoffrey A. Foxon

    1. Zeneca Seeds, Jealott’s Hill Research Station, Bracknell, Berks RG12 6EY, UK,, INRA CRA, Biochim, Macromol Vegetales,F-51686 Reims, France,, IACR-Long Ashton Research Station, Bristol BS18 9AF, UK, and, Department of Biological Sciences, University of Dundee, Dundee DD1 4HN, UK
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Summary

Brown-midrib (bm) mutants of maize have modified lignin of reddish-brown colour. Although four independent bm loci are known, only one of the mutant genes has been previously identified. We report here that maize bm1, one of the less characterised mutants, shows severely reduced CAD activity in lignified tissues, resulting in the production of a modified lignin. Both the total lignin content and the structure of the polymer are altered by the mutation. We further describe the isolation and characterisation of the maize CAD cDNA and mapping of the CAD gene. CAD maps very closely to the known location of bm1 and co-segregates with the bm1 locus in two independent recombinant inbred populations. These data strongly support the premise that maize bm1 directly affects expression of the CAD gene.

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