title: Diversity and association of phenotypic and metabolomic traits in the close model grasses Brachypodium distachyon, B. stacei and B. hybridum.
abstract: Morphological traits in combination with metabolite fingerprinting were used to investigate inter- and intraspecies diversity within the model annual grasses Brachypodium distachyon, Brachypodium stacei and Brachypodium hybridum .
  
  
  
  Phenotypic variation of 15 morphological characters and 2219 nominal mass ( m / z ) signals generated using flow infusion electrospray ionization-mass spectrometry (FIE-MS) were evaluated in individuals from a total of 174 wild populations and six inbred lines, and 12 lines, of the three species, respectively. Basic statistics and multivariate principal component analysis and discriminant analysis were used to differentiate inter- and intraspecific variability of the two types of variable, and their association was assayed with the rcorr function.
  
  
  
  Basic statistics and analysis of variance detected eight phenotypic characters [(stomata) leaf guard cell length, pollen grain length, (plant) height, second leaf width, inflorescence length, number of spikelets per inflorescence, lemma length, awn length] and 434 tentatively annotated metabolite signals that significantly discriminated the three species. Three phenotypic traits (pollen grain length, spikelet length, number of flowers per inflorescence) might be genetically fixed. The three species showed different metabolomic profiles. Discriminant analysis significantly discriminated the three taxa with both morphometric and metabolome traits and the intraspecific phenotypic diversity within B. distachyon and B. stacei . The populations of B. hybridum were considerably less differentiated.
  
  
  
  Highly explanatory metabolite signals together with morphological characters revealed concordant patterns of differentiation of the three taxa. Intraspecific phenotypic diversity was observed between northern and southern Iberian populations of B. distachyon and between eastern Mediterranean/south-western Asian and western Mediterranean populations of B. stacei . Significant association was found for pollen grain length and lemma length and ten and six metabolomic signals, respectively. These results would guide the selection of new germplasm lines of the three model grasses in ongoing genome-wide association studies.
authors.affiliation: Department of Agriculture and Environmental Sciences, High Polytechnic School of Huesca, University of Zaragoza, Ctra. Cuarte Km 1, 22071 Huesca, Spain.
authors.forename: Diana
authors.initials: D
authors.lastname: López-Álvarez
authors.affiliation: Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Plas Gogerddan, Aberystwyth SY23 3EB, UK.
authors.forename: Hassan
authors.initials: H
authors.lastname: Zubair
authors.affiliation: Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Plas Gogerddan, Aberystwyth SY23 3EB, UK.
authors.forename: Manfred
authors.initials: M
authors.lastname: Beckmann
authors.affiliation: Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Plas Gogerddan, Aberystwyth SY23 3EB, UK.
authors.forename: John
authors.initials: J
authors.lastname: Draper
authors.affiliation: Department of Agriculture and Environmental Sciences, High Polytechnic School of Huesca, University of Zaragoza, Ctra. Cuarte Km 1, 22071 Huesca, Spain.|Department of Botany, Institute of Biology, Tomsk State University, Lenin Av. 36, Tomsk 634050, Russia.
authors.forename: Pilar
authors.initials: P
authors.lastname: Catalán
mesh_terms: D058431:Brachypodium / Q000033:anatomy & histology / Q000235:genetics* / Q000378:metabolism; D035264:Flowers / Q000033:anatomy & histology; D014644:Genetic Variation / Q000235:genetics; D055432:Metabolomics; D010641:Phenotype; D018515:Plant Leaves / Q000033:anatomy & histology; D011058:Pollen / Q000648:ultrastructure; D021241:Spectrometry, Mass, Electrospray Ionization
keywords: Association studies; Brachypodium distachyon; Brachypodium hybridum; Brachypodium stacei; metabolite fingerprinting; phenotypic traits; statistical analyses