title: RNAi-mediated downregulation of poplar plasma membrane intrinsic proteins (PIPs) changes plasma membrane proteome composition and affects leaf physiology.
abstract: Plasma membrane intrinsic proteins (PIPs) are one subfamily of aquaporins that mediate the transmembrane transport of water. To reveal their function in poplar, we generated transgenic poplar plants in which the translation of PIP genes was downregulated by RNA interference investigated these plants with a comprehensive leaf plasma membrane proteome and physiome analysis. First, inhibition of PIP synthesis strongly altered the leaf plasma membrane protein composition. Strikingly, several signaling components and transporters involved in the regulation of stomatal movement were differentially regulated in transgenic poplars. Furthermore, hormonal crosstalk related to abscisic acid, auxin and brassinosteroids was altered, in addition to cell wall biosynthesis/cutinization, the organization of cellular structures and membrane trafficking. A physiological analysis confirmed the proteomic results. The leaves had wider opened stomata and higher net CO2 assimilation and transpiration rates as well as greater mesophyll conductance for CO2 (gm) and leaf hydraulic conductance (Kleaf). Based on these results, we conclude that PIP proteins not only play essential roles in whole leaf water and CO2 flux but have important roles in the regulation of stomatal movement.
authors.affiliation: Research Unit Environmental Simulation, Institute of Biochemical Plant Pathology, Helmholtz Zentrum München, Ingolstädter Landstr.1, 85764 Neuherberg, Germany.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Bi
authors.affiliation: Research Unit Protein Science-Core Facility Proteomics, Helmholtz Zentrum München, Ingolstädter Landstr.1, 85764 Neuherberg, Germany.
authors.forename: Juliane
authors.initials: J
authors.lastname: Merl-Pham
authors.affiliation: Institute of Applied Plant Science, University of Technology Darmstadt, Schnittspahndtr.10, 64287 Darmstadt, Germany.
authors.forename: Norbert
authors.initials: N
authors.lastname: Uehlein
authors.affiliation: Research Unit Environmental Simulation, Institute of Biochemical Plant Pathology, Helmholtz Zentrum München, Ingolstädter Landstr.1, 85764 Neuherberg, Germany.
authors.forename: Ina
authors.initials: I
authors.lastname: Zimmer
authors.affiliation: Research Unit Environmental Simulation, Institute of Biochemical Plant Pathology, Helmholtz Zentrum München, Ingolstädter Landstr.1, 85764 Neuherberg, Germany.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Mühlhans
authors.affiliation: Research Unit Analytical Pathology, Helmholtz Zentrum München, Ingolstädter Landstr.1, 85764 Neuherberg, Germany.
authors.forename: Michaela
authors.initials: M
authors.lastname: Aichler
authors.affiliation: Research Unit Analytical Pathology, Helmholtz Zentrum München, Ingolstädter Landstr.1, 85764 Neuherberg, Germany.
authors.forename: Axel Karl
authors.initials: AK
authors.lastname: Walch
authors.affiliation: Institute of Applied Plant Science, University of Technology Darmstadt, Schnittspahndtr.10, 64287 Darmstadt, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Kaldenhoff
authors.affiliation: BIOSS Centre for Biological Signalling Studies, ZBSA Centre for Biosystems Studies, Faculty of Biology, Schänzlestr. 1, University of Freiburg, 79104 Freiburg, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Palme
authors.affiliation: Research Unit Environmental Simulation, Institute of Biochemical Plant Pathology, Helmholtz Zentrum München, Ingolstädter Landstr.1, 85764 Neuherberg, Germany.
authors.forename: Jörg-Peter
authors.initials: JP
authors.lastname: Schnitzler
authors.affiliation: Research Unit Environmental Simulation, Institute of Biochemical Plant Pathology, Helmholtz Zentrum München, Ingolstädter Landstr.1, 85764 Neuherberg, Germany. Electronic address: katja.block@helmholtz-muenchen.de.
authors.forename: Katja
authors.initials: K
authors.lastname: Block
mesh_terms: D020346:Aquaporins / Q000378:metabolism*; D015536:Down-Regulation / Q000502:physiology; D020868:Gene Silencing / Q000502:physiology; D018515:Plant Leaves; D010940:Plant Proteins / Q000378:metabolism*; D018526:Plant Transpiration / Q000502:physiology*; D030821:Plants, Genetically Modified / Q000502:physiology; D032107:Populus / Q000502:physiology*; D020543:Proteome / Q000378:metabolism*; D034622:RNA Interference / Q000502:physiology*
chemical_list: D020346:Aquaporins; D010940:Plant Proteins; D020543:Proteome; C110065:major intrinsic protein, plant
keywords: Aquaporin; PIP; Photosynthesis; Plasma membrane proteomics; Populus×canescens; Stomatal movement; plasma membrane intrinsic protein