ARS | Publication request: Identification of novel brown-midrib (bm) genes in maize by tests of allelism

Submitted to: Plant Breeding
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 16, 2010
Publication Date: July 21, 2010
Repository URL: http://onlinelibrary.wiley.com/doi/10.1111/j.1439-0523.2010.01791.x/full
Citation: Ali, F., Scott, M.P., Bakht, J., Chen, Y., Lubberstedt, T. 2010. Identification of novel brown-midrib genes in maize by tests of allelism. Plant Breeding. 129:724-726.

Interpretive Summary: Lignin is an important structural compund in plant cell walls. Lignin content is related to how well maize plants stand in the field. Lignin also influences the suitability of maize for biofuel production. Several genes involved in lignin biosynthesis have a brown midrib phenotype. A number of mutant lines with this phenotype have not been characterized at the molecular level, but it is likely they are somehow involved in lignin biosynthesis. We characterized these mutants genetically and determined that they define two new brown midrib genes as well as additional alleles of previously characterized genes. Further characterization of these new genes will lead to better understanding of lignin biosynthesis in maize. This work will benefit scientists who study lignin biosynthesis in maize.

Technical Abstract: Brown midrib (bm) mutations are known to affect cell wall digestibility by altering the quantity and composition of lignins in cell walls, resulting in higher ethanol yield and increased cell wall digestibility. So far, four bm genes (bm1, bm2, bm3, and bm4) were identified and mapped in maize, the last one (bm4) in 1947. In this study, thirteen spontaneous mutations (bm*A-M) resulting in the appearance of brown midribs were crossed with bm1-4 for tests of allelism. From these tests, we report three new bm mutants bm5 (bm*F), and bm6 (bm*J), while other bm* lines were either found allelic to bm1-4 or to one of the bm* lines.