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

• Published in: The Plant journal : for cell and molecular biology 1998-06, Vol.14 (5), p.545-553
• Main Authors: Halpin, C, Holt, K, Chojecki, J, Oliver, D, Chabbert, B, Monties, B, Edwards, K, Barakate, A, Foxon, G.A
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; alcohol oxidoreductases; Alcohol Oxidoreductases - biosynthesis; Alcohol Oxidoreductases - chemistry; Alcohol Oxidoreductases - genetics; Amino Acid Sequence; amino acid sequences; Biological and medical sciences; chemical constituents of plants; chemical structure; Chromosome Mapping; Cloning, Molecular; Color; complementary DNA; DNA, Complementary; enzyme activity; Fundamental and applied biological sciences. Psychology; genbank/aj005702; gene expression; genetic markers; Genetics; Genetics and breeding of economic plants; inbred lines; Life Sciences; lignin; Lignin - biosynthesis; Lignin - chemistry; loci; Metabolism; Molecular Sequence Data; Mutagenesis; Mutation; nucleotide sequences; Oligonucleotide Probes; Plant breeding: fundamental aspects and methodology; Plant physiology and development; plant vascular system; Plants genetics; Recombinant Proteins - biosynthesis; Recombinant Proteins - chemistry; segregation; Sequence Alignment; Sequence Homology, Amino Acid; Storage and secretion, pigments, phytochrome; Zea mays; Zea mays - enzymology; Zea mays - genetics
• ISSN: 0960-7412; 1365-313X
• DOI: 10.1046/j.1365-313x.1998.00153.x

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.