title: Reduced nighttime transpiration is a relevant breeding target for high water-use efficiency in grapevine.
abstract: Increasing water scarcity challenges crop sustainability in many regions. As a consequence, the enhancement of transpiration efficiency (TE)-that is, the biomass produced per unit of water transpired-has become crucial in breeding programs. This could be achieved by reducing plant transpiration through a better closure of the stomatal pores at the leaf surface. However, this strategy generally also lowers growth, as stomatal opening is necessary for the capture of atmospheric CO2 that feeds daytime photosynthesis. Here, we considered the reduction in transpiration rate at night (En) as a possible strategy to limit water use without altering growth. For this purpose, we carried out a genetic analysis for En and TE in grapevine, a major crop in drought-prone areas. Using recently developed phenotyping facilities, potted plants of a cross between Syrah and Grenache cultivars were screened for 2 y under well-watered and moderate soil water deficit scenarios. High genetic variability was found for En under both scenarios and was primarily associated with residual diffusion through the stomata. Five quantitative trait loci (QTLs) were detected that underlay genetic variability in En Interestingly, four of them colocalized with QTLs for TE. Moreover, genotypes with favorable alleles on these common QTLs exhibited reduced En without altered growth. These results demonstrate the interest of breeding grapevine for lower water loss at night and pave the way to breeding other crops with this underexploited trait for higher TE.
authors.affiliation: UMR Laboratoire d'Ecophysiologie des Plantes sous Stress Environnementaux (LEPSE), Institut National de la Recherche Agronomique (INRA), Montpellier SupAgro, 34060 Montpellier, France; thierry.simonneau@supagro.inra.fr aude.coupel-ledru@supagro.inra.fr.
authors.forename: Aude
authors.initials: A
authors.lastname: Coupel-Ledru
authors.affiliation: UMR Laboratoire d'Ecophysiologie des Plantes sous Stress Environnementaux (LEPSE), Institut National de la Recherche Agronomique (INRA), Montpellier SupAgro, 34060 Montpellier, France;
authors.forename: Eric
authors.initials: E
authors.lastname: Lebon
authors.affiliation: UMR Laboratoire d'Ecophysiologie des Plantes sous Stress Environnementaux (LEPSE), Institut National de la Recherche Agronomique (INRA), Montpellier SupAgro, 34060 Montpellier, France;
authors.forename: Angélique
authors.initials: A
authors.lastname: Christophe
authors.affiliation: UMR Laboratoire d'Ecophysiologie des Plantes sous Stress Environnementaux (LEPSE), Institut National de la Recherche Agronomique (INRA), Montpellier SupAgro, 34060 Montpellier, France;
authors.forename: Agustina
authors.initials: A
authors.lastname: Gallo
authors.affiliation: Misión Biológica de Galicia, Consejo Superior de Investigaciones Científicas (MBG-CSIC), 36143 Pontevedra, Spain;
authors.forename: Pilar
authors.initials: P
authors.lastname: Gago
authors.affiliation: UMR Laboratoire d'Ecophysiologie des Plantes sous Stress Environnementaux (LEPSE), Institut National de la Recherche Agronomique (INRA), Montpellier SupAgro, 34060 Montpellier, France;
authors.forename: Florent
authors.initials: F
authors.lastname: Pantin
authors.affiliation: UMR Amélioration Génétique et Adaptation des Plantes méditerranéennes et tropicales (AGAP), Institut National de la Recherche Agronomique (INRA), F-34060 Montpellier, France.
authors.forename: Agnès
authors.initials: A
authors.lastname: Doligez
authors.affiliation: UMR Laboratoire d'Ecophysiologie des Plantes sous Stress Environnementaux (LEPSE), Institut National de la Recherche Agronomique (INRA), Montpellier SupAgro, 34060 Montpellier, France; thierry.simonneau@supagro.inra.fr aude.coupel-ledru@supagro.inra.fr.
authors.forename: Thierry
authors.initials: T
authors.lastname: Simonneau
mesh_terms: D001947:Breeding; D018556:Crops, Agricultural; D018526:Plant Transpiration; D040641:Quantitative Trait Loci; D027843:Vitis / Q000235:genetics / Q000502:physiology*; D014867:Water / Q000378:metabolism*
chemical_list: D014867:Water
keywords: QTL; growth; night transpiration; stomata; transpiration efficiency