title: Genome-wide association mapping of leaf metabolic profiles for dissecting complex traits in maize.
abstract: The diversity of metabolites found in plants is by far greater than in most other organisms. Metabolic profiling techniques, which measure many of these compounds simultaneously, enabled investigating the regulation of metabolic networks and proved to be useful for predicting important agronomic traits. However, little is known about the genetic basis of metabolites in crops such as maize. Here, a set of 289 diverse maize inbred lines was genotyped with 56,110 SNPs and assayed for 118 biochemical compounds in the leaves of young plants, as well as for agronomic traits of mature plants in field trials. Metabolite concentrations had on average a repeatability of 0.73 and showed a correlation pattern that largely reflected their functional grouping. Genome-wide association mapping with correction for population structure and cryptic relatedness identified for 26 distinct metabolites strong associations with SNPs, explaining up to 32.0% of the observed genetic variance. On nine chromosomes, we detected 15 distinct SNP-metabolite associations, each of which explained more then 15% of the genetic variance. For lignin precursors, including p-coumaric acid and caffeic acid, we found strong associations (P values   to  ) with a region on chromosome 9 harboring cinnamoyl-CoA reductase, a key enzyme in monolignol synthesis and a target for improving the quality of lignocellulosic biomass by genetic engineering approaches. Moreover, lignin precursors correlated significantly with lignin content, plant height, and dry matter yield, suggesting that metabolites represent promising connecting links for narrowing the genotype-phenotype gap of complex agronomic traits.
authors.affiliation: Institute of Plant Breeding, Seed Science and Population Genetics,  University of Hohenheim, 70593 Stuttgart,  Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Riedelsheimer
authors.forename: Jan
authors.initials: J
authors.lastname: Lisec
authors.forename: Angelika
authors.initials: A
authors.lastname: Czedik-Eysenberg
authors.forename: Ronan
authors.initials: R
authors.lastname: Sulpice
authors.forename: Anna
authors.initials: A
authors.lastname: Flis
authors.forename: Christoph
authors.initials: C
authors.lastname: Grieder
authors.forename: Thomas
authors.initials: T
authors.lastname: Altmann
authors.forename: Mark
authors.initials: M
authors.lastname: Stitt
authors.forename: Lothar
authors.initials: L
authors.lastname: Willmitzer
authors.forename: Albrecht E
authors.initials: AE
authors.lastname: Melchinger
mesh_terms: D000445:Aldehyde Oxidoreductases / Q000235:genetics; D002109:Caffeic Acids; D002874:Chromosome Mapping; D003373:Coumaric Acids; D014644:Genetic Variation; D018745:Genome, Plant / Q000235:genetics*; D055106:Genome-Wide Association Study; D005838:Genotype; D055442:Metabolome / Q000235:genetics*; D055432:Metabolomics / Q000379:methods; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D011422:Propionates; D003313:Zea mays / Q000235:genetics*
chemical_list: D002109:Caffeic Acids; D003373:Coumaric Acids; D011422:Propionates; D000445:Aldehyde Oxidoreductases; C019904:cinnamoyl CoA reductase; C495469:p-coumaric acid; C040048:caffeic acid