Quantitative Trait Loci and Comparative Genomics of Cereal Cell Wall Composition

Abstract

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.

Precise Mapping of Quantitative Trait Loci for Resistance to Southern Leaf Blight, Caused by Cochliobolus heterostrophus Race O, and Flowering Time Using Advanced Intercross Maize Lines

“…The IBM population also has a relatively large population size, with $300 lines being available. The authors are aware of only one published mapping study using the full IBM population (Hazen et al 2003), in which QTL for cell wall composition were mapped to intervals spanning $10 cM. Another published study used 94 lines of the IBM population to map QTL controlling the thermal properties of maize starch (Scott and Duvick 2005).…”

“…Therefore, the major significant difference between this previous study and the study reported here, apart from the years in which they were conducted, was that, in the present study, an independently derived B73 3 Mo17 AIL population was employed. AIL populations have been used successfully in animals and plants to localize QTL to relatively narrow chromosomal segments (e.g., Hazen et al 2003;Wang et al 2003). Studies in mice found greater precision of QTL detection in an F 11 AIL population compared to an F 2 population (Iraqi et al 2000;Hernandez-Valladares et al 2004).…”

The Genetic Architecture of Grain Yield and Related Traits in Zea maize L. Revealed by Comparing Intermated and Conventional Populations

“…Mapping experiments using AILs in animals and plants have been published (Iraqi et al 2000;Hazen et al 2003;Wang et al 2003;Jagodic et al 2004;Hernandez-Valladares et al 2004;Scott and Duvick 2005;Yu et al 2007;Balint-Kurti et al 2007Rodriguez et al 2008;Capelle et al 2010). In maize, the IBM population (for Intermated B73 3 Mo17, Lee et al 2002), is widely used by the maize international community for high-density genetic mapping Fu et al 2006) and fine mapping of traits of interest (Hazen et al 2003;Scott and Duvick 2005;Balint-Kurti et al 2007Rodriguez et al 2008).…”

“…In maize, the IBM population (for Intermated B73 3 Mo17, Lee et al 2002), is widely used by the maize international community for high-density genetic mapping Fu et al 2006) and fine mapping of traits of interest (Hazen et al 2003;Scott and Duvick 2005;Balint-Kurti et al 2007Rodriguez et al 2008). Balint-Kurti et al (2007 were the first to compare the precision of QTL detection in conventional recombinant inbred lines (RILs) and intermated RILs, derived from the same parental lines, for two disease resistance traits in maize.…”

Improving Enzymes for Biomass Conversion: A Basic Research Perspective

“…Whereas cellulose is chemically homogeneous and available in highly pure forms, hemicelluloses are more diverse, both between plant species and between tissues within a single plant. Dicotyledonous hemicelluloses, for example, contain fucose, O-acetylated galactose, and α1,6-xylose-substituted β1,4-glucan [10,19,46]. Enzymes that are necessary to degrade the linkages found in dicot hemicelluloses therefore include β1,4-glucanases (which can be specialized for hemicelluloses such as xyloglucan), α-fucosidase, α-glucuronidase, β1,4-xylanase, α-and β-xylosidase, α-arabinosidase, and several classes of esterase.…”