title: Modeling development and quantitative trait mapping reveal independent genetic modules for leaf size and shape.
abstract: Improved predictions of fitness and yield may be obtained by characterizing the genetic controls and environmental dependencies of organismal ontogeny. Elucidating the shape of growth curves may reveal novel genetic controls that single-time-point (STP) analyses do not because, in theory, infinite numbers of growth curves can result in the same final measurement. We measured leaf lengths and widths in Brassica rapa recombinant inbred lines (RILs) throughout ontogeny. We modeled leaf growth and allometry as function valued traits (FVT), and examined genetic correlations between these traits and aspects of phenology, physiology, circadian rhythms and fitness. We used RNA-seq to construct a SNP linkage map and mapped trait quantitative trait loci (QTL). We found genetic trade-offs between leaf size and growth rate FVT and uncovered differences in genotypic and QTL correlations involving FVT vs STPs. We identified leaf shape (allometry) as a genetic module independent of length and width and identified selection on FVT parameters of development. Leaf shape is associated with venation features that affect desiccation resistance. The genetic independence of leaf shape from other leaf traits may therefore enable crop optimization in leaf shape without negative effects on traits such as size, growth rate, duration or gas exchange.
authors.affiliation: Department of Botany, University of Wyoming, Laramie, WY, 82071, USA.
authors.forename: Robert L
authors.initials: RL
authors.lastname: Baker
authors.affiliation: Department of Agronomy, Kansas State University, Manhattan, KS, 66506, USA.
authors.forename: Wen Fung
authors.initials: WF
authors.lastname: Leong
authors.affiliation: Department of Botany, University of Wyoming, Laramie, WY, 82071, USA.
authors.forename: Marcus T
authors.initials: MT
authors.lastname: Brock
authors.affiliation: Department of Plant Biology, University of California, Davis, CA, 95616, USA.
authors.forename: R J Cody
authors.initials: RJ
authors.lastname: Markelz
authors.affiliation: Department of Plant Biology, University of California, Davis, CA, 95616, USA.
authors.forename: Michael F
authors.initials: MF
authors.lastname: Covington
authors.affiliation: Department of Plant Biology, University of California, Davis, CA, 95616, USA.
authors.forename: Upendra K
authors.initials: UK
authors.lastname: Devisetty
authors.affiliation: Center for Conservation and Sustainable Development, Missouri Botanical Garden, St Louis, MO, 63166, USA.
authors.forename: Christine E
authors.initials: CE
authors.lastname: Edwards
authors.affiliation: Department of Plant Biology, University of California, Davis, CA, 95616, USA.
authors.forename: Julin
authors.initials: J
authors.lastname: Maloof
authors.affiliation: Department of Agronomy, Kansas State University, Manhattan, KS, 66506, USA.
authors.forename: Stephen
authors.initials: S
authors.lastname: Welch
authors.affiliation: Department of Botany, University of Wyoming, Laramie, WY, 82071, USA.|Department of Molecular Biology, University of Wyoming, Laramie, WY, 82071, USA.
authors.forename: Cynthia
authors.initials: C
authors.lastname: Weinig
mesh_terms: D000222:Adaptation, Physiological; D018533:Biomass; D029741:Brassica rapa / Q000033:anatomy & histology / Q000235:genetics* / Q000254:growth & development; D002874:Chromosome Mapping; D055864:Droughts; D004777:Environment; D053263:Gene Regulatory Networks; D017343:Genes, Plant; D008040:Genetic Linkage; D005838:Genotype; D008954:Models, Biological; D010641:Phenotype; D018515:Plant Leaves / Q000033:anatomy & histology / Q000254:growth & development; D020641:Polymorphism, Single Nucleotide; D040641:Quantitative Trait Loci; D017423:Sequence Analysis, RNA; D014867:Water
chemical_list: D014867:Water
keywords: Brassica rapa; allometry; function valued traits; growth modeling; leaf development; modularity; quantitative genetics; quantitative trait locus (QTL) mapping