title: Breeding maize for silage and biofuel production, an illustration of a step forward with the genome sequence.
abstract: The knowledge of the gene families mostly impacting cell wall digestibility variations would significantly increase the efficiency of marker-assisted selection when breeding maize and grass varieties with improved silage feeding value and/or with better straw fermentability into alcohol or methane. The maize genome sequence of the B73 inbred line was released at the end of 2009, opening up new avenues to identify the genetic determinants of quantitative traits. Colocalizations between a large set of candidate genes putatively involved in secondary cell wall assembly and QTLs for cell wall digestibility (IVNDFD) were then investigated, considering physical positions of both genes and QTLs. Based on available data from six RIL progenies, 59 QTLs corresponding to 38 non-overlapping positions were matched up with a list of 442 genes distributed all over the genome. Altogether, 176 genes colocalized with IVNDFD QTLs and most often, several candidate genes colocalized at each QTL position. Frequent QTL colocalizations were found firstly with genes encoding ZmMYB and ZmNAC transcription factors, and secondly with genes encoding zinc finger, bHLH, and xylogen regulation factors. In contrast, close colocalizations were less frequent with genes involved in monolignol biosynthesis, and found only with the C4H2, CCoAOMT5, and CCR1 genes. Close colocalizations were also infrequent with genes involved in cell wall feruloylation and cross-linkages. Altogether, investigated colocalizations between candidate genes and cell wall digestibility QTLs suggested a prevalent role of regulation factors over constitutive cell wall genes on digestibility variations.
authors.affiliation: INRA, UR889, Unité de Génétique et d'Amélioration des Plantes Fourragères, 86600 Lusignan, France. Electronic address: yves.barriere@lusignan.inra.fr.
authors.forename: Yves
authors.initials: Y
authors.lastname: Barrière
authors.affiliation: LRSV, Laboratoire de Recherche en Sciences Végétales, UMR5546, Université Paul Sabatier Toulouse III / CNRS, Auzeville, BP 42617, 31326 Castanet-Tolosan, France; INRA, US1258, Centre National de Ressources Génomiques Végétales, CS 52627, 31326 Castanet-Tolosan, France.
authors.forename: Audrey
authors.initials: A
authors.lastname: Courtial
authors.affiliation: INRA, UR1268 Biopolymères, Interactions, Assemblages, 44316 Nantes, France.
authors.forename: Anne-Laure
authors.initials: AL
authors.lastname: Chateigner-Boutin
authors.affiliation: INRA, UR889, Unité de Génétique et d'Amélioration des Plantes Fourragères, 86600 Lusignan, France.
authors.forename: Dominique
authors.initials: D
authors.lastname: Denoue
authors.affiliation: LRSV, Laboratoire de Recherche en Sciences Végétales, UMR5546, Université Paul Sabatier Toulouse III / CNRS, Auzeville, BP 42617, 31326 Castanet-Tolosan, France.
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Grima-Pettenati
mesh_terms: D056804:Biofuels; D002473:Cell Wall / Q000235:genetics / Q000378:metabolism; D002874:Chromosome Mapping; D032461:Chromosomes, Plant / Q000235:genetics; D017343:Genes, Plant / Q000235:genetics; D018745:Genome, Plant / Q000235:genetics*; D023281:Genomics / Q000379:methods; D053858:Metabolic Networks and Pathways / Q000235:genetics; D000069600:Plant Breeding / Q000379:methods*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D040641:Quantitative Trait Loci / Q000235:genetics; D017422:Sequence Analysis, DNA; D012820:Silage; D003313:Zea mays / Q000235:genetics* / Q000378:metabolism
chemical_list: D056804:Biofuels; D010940:Plant Proteins
keywords: Bioenergy; Bioethanol; Candidate gene; Cell wall; Digestibility; Maize; QTL; Silage