title: Linkage drag constrains the roots of modern wheat.
abstract: Roots, the hidden half of crop plants, are essential for resource acquisition. However, knowledge about the genetic control of below-ground plant development in wheat, one of the most important small-grain crops in the world, is very limited. The molecular interactions connecting root and shoot development and growth, and thus modulating the plant's demand for water and nutrients along with its ability to access them, are largely unexplored. Here, we demonstrate that linkage drag in European bread wheat, driven by strong selection for a haplotype variant controlling heading date, has eliminated a specific combination of two flanking, highly conserved haplotype variants whose interaction confers increased root biomass. Reversing this inadvertent consequence of selection could recover root diversity that may prove essential for future food production in fluctuating environments. Highly conserved synteny to rice across this chromosome segment suggests that adaptive selection has shaped the diversity landscape of this locus across different, globally important cereal crops. By mining wheat gene expression data, we identified root-expressed genes within the region of interest that could help breeders to select positive variants adapted to specific target soil environments.
authors.affiliation: Department of Plant Breeding, IFZ Research Centre for Biosystems, Land Use and Nutrition, Justus Liebig University, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany.
authors.forename: Kai P
authors.initials: KP
authors.lastname: Voss-Fels
authors.affiliation: Department of Plant Breeding, IFZ Research Centre for Biosystems, Land Use and Nutrition, Justus Liebig University, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany.
authors.forename: Lunwen
authors.initials: L
authors.lastname: Qian
authors.affiliation: Department of Agronomy, University of Rostock, Justus-von-Liebig-Weg 6, 18059, Rostock, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Parra-Londono
authors.affiliation: Department of Agronomy, University of Rostock, Justus-von-Liebig-Weg 6, 18059, Rostock, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Uptmoor
authors.affiliation: Department of Biometry and Population Genetics, IFZ Research Centre for Biosystems, Land Use and Nutrition, Justus Liebig University, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Frisch
authors.affiliation: AgriBio, Centre for AgriBioscience, Department of Economic Development, Jobs, Transport and Resources (DEDJTR), Bundoora, Victoria, 3083, Australia.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Keeble-Gagnère
authors.affiliation: State Agriculture Biotechnology Centre, School of Veterinary and Life Sciences, Murdoch University, Australia Export Grains Innovation Centre (AEGIC), Perth, WA, 6150, Australia.
authors.forename: Rudi
authors.initials: R
authors.lastname: Appels
authors.affiliation: Department of Plant Breeding, IFZ Research Centre for Biosystems, Land Use and Nutrition, Justus Liebig University, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany.
authors.forename: Rod J
authors.identifier: http://orcid.org/0000-0003-0782-366X
authors.initials: RJ
authors.lastname: Snowdon
mesh_terms: D018533:Biomass; D032461:Chromosomes, Plant / Q000235:genetics; D017753:Ecosystem; D004843:Epistasis, Genetic; D017343:Genes, Plant; D008040:Genetic Linkage; D055106:Genome-Wide Association Study; D006239:Haplotypes / Q000235:genetics; D063245:Plant Development / Q000235:genetics; D018517:Plant Roots / Q000235:genetics* / Q000254:growth & development; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D040641:Quantitative Trait Loci / Q000235:genetics; D019655:Quantitative Trait, Heritable; D015203:Reproducibility of Results; D036226:Seedlings / Q000235:genetics; D014908:Triticum / Q000235:genetics*
keywords: GWAS; Genome-wide association study; LD; Triticum aestivum L. (wheat); genomics; linkage disequilibrium