title: Leveraging abscisic acid receptors for efficient water use in Arabidopsis.
abstract: Plant growth requires the influx of atmospheric CO2 through stomatal pores, and this carbon uptake for photosynthesis is inherently associated with a large efflux of water vapor. Under water deficit, plants reduce transpiration and are able to improve carbon for water exchange leading to higher water use efficiency (WUE). Whether increased WUE can be achieved without trade-offs in plant growth is debated. The signals mediating the WUE response under water deficit are not fully elucidated but involve the phytohormone abscisic acid (ABA). ABA is perceived by a family of related receptors known to mediate acclimation responses and to reduce transpiration. We now show that enhanced stimulation of ABA signaling via distinct ABA receptors can result in plants constitutively growing at high WUE in the model species Arabidopsis WUE was assessed by three independent approaches involving gravimetric analyses, (13)C discrimination studies of shoots and derived cellulose fractions, and by gas exchange measurements of whole plants and individual leaves. Plants expressing the ABA receptors RCAR6/PYL12 combined up to 40% increased WUE with high growth rates, i.e., are water productive. Water productivity was associated with maintenance of net carbon assimilation by compensatory increases of leaf CO2 gradients, thereby sustaining biomass acquisition. Leaf surface temperatures and growth potentials of plants growing under well-watered conditions were found to be reliable indicators for water productivity. The study shows that ABA receptors can be explored to generate more plant biomass per water transpired, which is a prime goal for a more sustainable water use in agriculture.
authors.affiliation: Lehrstuhl für Botanik, Technische Universität München, 85354 Freising, Germany;
authors.forename: Zhenyu
authors.initials: Z
authors.lastname: Yang
authors.affiliation: Lehrstuhl für Botanik, Technische Universität München, 85354 Freising, Germany;
authors.forename: Jinghui
authors.initials: J
authors.lastname: Liu
authors.affiliation: Lehrstuhl für Botanik, Technische Universität München, 85354 Freising, Germany;
authors.forename: Stefanie V
authors.initials: SV
authors.lastname: Tischer
authors.affiliation: Lehrstuhl für Botanik, Technische Universität München, 85354 Freising, Germany;
authors.forename: Alexander
authors.initials: A
authors.lastname: Christmann
authors.affiliation: Lehrstuhl für Tierernährung, Technische Universität München, 85354 Freising, Germany;
authors.forename: Wilhelm
authors.initials: W
authors.lastname: Windisch
authors.affiliation: Lehrstuhl für Grünlandlehre, Technische Universität München, 85354 Freising, Germany.
authors.forename: Hans
authors.initials: H
authors.lastname: Schnyder
authors.affiliation: Lehrstuhl für Botanik, Technische Universität München, 85354 Freising, Germany; grill@wzw.tum.de.
authors.forename: Erwin
authors.initials: E
authors.lastname: Grill
mesh_terms: D000040:Abscisic Acid / Q000235:genetics / Q000378:metabolism*; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002245:Carbon Dioxide / Q000378:metabolism; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D014867:Water / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D014867:Water; D002245:Carbon Dioxide; D000040:Abscisic Acid
keywords: carbon assimilation; drought resistance; water deficit; water productivity; water use efficiency