title: PIP1 plasma membrane aquaporins in tobacco: from cellular effects to function in plants.
abstract: The molecular functions of several aquaporins are well characterized (e.g., by analysis of aquaporin-expressing Xenopus oocytes). However, their significance in the physiology of water transport in multicellular organisms remains uncertain. The tobacco plasma membrane aquaporin NtAQP1 was used to elucidate this issue. By comparing antisense plants that were inhibited in NtAQP1 expression with control plants, we found evidence for NtAQP1 function in cellular and whole-plant water relations. The consequences of a decrease in cellular water permeability were determined by measurement of transpiration rate and stem and leaf water potential as well as growth experiments under extreme soil water depletion. Plants impaired in NtAQP1 expression showed reduced root hydraulic conductivity and lower water stress resistance. In conclusion, our results emphasize the importance of symplastic aquaporin-mediated water transport in whole-plant water relations.
authors.affiliation: Department of Plant Physiology and Biophysics, University of Würzburg, D-97082 Würzburg, Germany.
authors.forename: Franka
authors.initials: F
authors.lastname: Siefritz
authors.forename: Melvin T
authors.initials: MT
authors.lastname: Tyree
authors.forename: Claudio
authors.initials: C
authors.lastname: Lovisolo
authors.forename: Andrea
authors.initials: A
authors.lastname: Schubert
authors.forename: Ralf
authors.initials: R
authors.lastname: Kaldenhoff
mesh_terms: D051398:Aquaporin 1; D020346:Aquaporins / Q000235:genetics* / Q000502:physiology; D001692:Biological Transport; D016373:DNA, Antisense / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology; D008969:Molecular Sequence Data; D009997:Osmotic Pressure; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism; D018526:Plant Transpiration / Q000235:genetics / Q000502:physiology; D030821:Plants, Genetically Modified; D014026:Nicotiana / Q000235:genetics* / Q000378:metabolism; D014867:Water / Q000378:metabolism / Q000494:pharmacology
chemical_list: D020346:Aquaporins; D016373:DNA, Antisense; D008565:Membrane Proteins; D014867:Water; D051398:Aquaporin 1