title: High resolution mapping of traits related to whole-plant transpiration under increasing evaporative demand in wheat.
abstract: Atmospheric vapor pressure deficit (VPD) is a key component of drought and has a strong influence on yields. Whole-plant transpiration rate (TR) response to increasing VPD has been linked to drought tolerance in wheat, but because of its challenging phenotyping, its genetic basis remains unexplored. Further, the genetic control of other key traits linked to daytime TR such as leaf area, stomata densities and - more recently - nocturnal transpiration remains unknown. Considering the presence of wheat phenology genes that can interfere with drought tolerance, the aim of this investigation was to identify at an enhanced resolution the genetic basis of the above traits while investigating the effects of phenology genes Ppd-D1 and Ppd-B1 Virtually all traits were highly heritable (heritabilities from 0.61 to 0.91) and a total of mostly trait-specific 68 QTL were detected. Six QTL were identified for TR response to VPD, with one QTL (QSLP.ucl-5A) individually explaining 25.4% of the genetic variance. This QTL harbored several genes previously reported to be involved in ABA signaling, interaction with DREB2A and root hydraulics. Surprisingly, nocturnal TR and stomata densities on both leaf sides were characterized by highly specific and robust QTL. In addition, negative correlations were found between TR and leaf area suggesting trade-offs between these traits. Further, Ppd-D1 had strong but opposite effects on these traits, suggesting an involvement in this trade-off. Overall, these findings revealed novel genetic resources while suggesting a more direct role of phenology genes in enhancing wheat drought tolerance.
authors.affiliation: Earth and Life Institute, Université Catholique de Louvain, Croix du Sud 2, L7.05.14, 1348 Louvain-la-Neuve, Belgium.
authors.forename: Rémy
authors.initials: R
authors.lastname: Schoppach
authors.affiliation: School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, PMB 1, Glen Osmond, South Australia SA 5064, Australia.
authors.forename: Julian D
authors.initials: JD
authors.lastname: Taylor
authors.affiliation: Earth and Life Institute, Université Catholique de Louvain, Croix du Sud 2, L7.05.14, 1348 Louvain-la-Neuve, Belgium.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Majerus
authors.affiliation: Earth and Life Institute, Université Catholique de Louvain, Croix du Sud 2, L7.05.14, 1348 Louvain-la-Neuve, Belgium.
authors.forename: Elodie
authors.initials: E
authors.lastname: Claverie
authors.affiliation: Australian Centre for Plant Functional Genomics (ACPFG), University of Adelaide, PMB 1, Glen Osmond, SA 5064, Australia.
authors.forename: Ute
authors.initials: U
authors.lastname: Baumann
authors.affiliation: Australian Centre for Plant Functional Genomics (ACPFG), University of Adelaide, PMB 1, Glen Osmond, SA 5064, Australia.
authors.forename: Radoslaw
authors.initials: R
authors.lastname: Suchecki
authors.affiliation: Australian Centre for Plant Functional Genomics (ACPFG), University of Adelaide, PMB 1, Glen Osmond, SA 5064, Australia.
authors.forename: Delphine
authors.initials: D
authors.lastname: Fleury
authors.affiliation: Department of Agronomy and Plant Genetics, University of Minnesota, 411 Borlaug Hall, 1991 Upper Buford Circle, St. Paul, MN 55108, USA msadok@umn.edu.
authors.forename: Walid
authors.initials: W
authors.lastname: Sadok
mesh_terms: D003681:Dehydration; D017343:Genes, Plant / Q000235:genetics / Q000502:physiology; D014644:Genetic Variation; D018515:Plant Leaves / Q000502:physiology; D054046:Plant Stomata / Q000235:genetics / Q000502:physiology; D018526:Plant Transpiration / Q000235:genetics / Q000502:physiology*; D040641:Quantitative Trait Loci / Q000235:genetics; D019655:Quantitative Trait, Heritable; D014908:Triticum / Q000235:genetics / Q000502:physiology*; D055548:Vapor Pressure
keywords: DREB2A; Ppd-D1; QTL; Triticum aestivum; drought; leaf area; night-time transpiration; phenology genes; plant hydraulics; stomata conductance; vapor pressure deficit.