Plant Physiol, May 2003, Vol. 132, pp. 263-271

Quantitative Trait Loci and Comparative Genomics of Cereal Cell Wall Composition¹

Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824 (S.P.H., R.M.H., J.D.W.); Department of Agronomy, University of Missouri, Columbia, Missouri 65211 (G.L.D.); Architecture et Fonction des Macromolécules Biologiques, Unité Mixte de Recherche 6098, Centre National de la Recherche Scientifique, Universités de Marseille I and II, 31 Chemin Joseph Aiguier, 13402 Marseille cedex 20, France (B.H.)

Quantitative trait loci (QTLs) affecting sugar composition of the cell walls of maize (Zea mays) pericarp were mapped as an approach to the identification of genes involved in cereal wall biosynthesis. Mapping was performed using the IBM (B73 × Mo17) recombinant inbred line population. There were statistically significant differences between B73 and Mo17 in content of xylose (Xyl), arabinose (Ara), galactose (Gal), and glucose. Thirteen QTLs were found, affecting the content of Xyl (two QTLs), Ara (two QTLs), Gal (five QTLs), Glc (two QTLs), Ara + Gal (one QTL), and Xyl + Glc (one QTL). The chromosomal regions corresponding to two of these, affecting Ara + Gal and Ara on maize chromosome 3, could be aligned with a syntenic region on rice (Oryza sativa) chromosome 1, which has been completely sequenced and annotated. The contiguous P1-derived artificial chromosome rice clones covering the QTLs were predicted to encode 117 and 125 proteins, respectively. Two of these genes encode putative glycosyltransferases, displaying similarity to carbohydrate-active enzyme database family GT4 (galactosyltransferases) or to family GT64 (C-terminal domain of animal heparan synthases). The results illustrate the potential of using natural variation, emerging genomic resources, and homeology within the Poaceae to identify candidate genes involved in the essential process of cell wall biosynthesis.