title: Reduced V-ATPase activity in the trans-Golgi network causes oxylipin-dependent hypocotyl growth Inhibition in Arabidopsis.
abstract: Regulated cell expansion allows plants to adapt their morphogenesis to prevailing environmental conditions. Cell expansion is driven by turgor pressure created by osmotic water uptake and is restricted by the extensibility of the cell wall, which in turn is regulated by the synthesis, incorporation, and cross-linking of new cell wall components. The vacuolar H(+)-ATPase (V-ATPase) could provide a way to coordinately regulate turgor pressure and cell wall synthesis, as it energizes the secondary active transport of solutes across the tonoplast and also has an important function in the trans-Golgi network (TGN), which affects synthesis and trafficking of cell wall components. We have previously shown that det3, a mutant with reduced V-ATPase activity, has a severe defect in cell expansion. However, it was not clear if this is caused by a defect in turgor pressure or in cell wall synthesis. Here, we show that inhibition of the tonoplast-localized V-ATPase subunit isoform VHA-a3 does not impair cell expansion. By contrast, inhibition of the TGN-localized isoform VHA-a1 is sufficient to restrict cell expansion. Furthermore, we provide evidence that the reduced hypocotyl cell expansion in det3 is conditional and due to active, hormone-mediated growth inhibition caused by a cell wall defect.
authors.affiliation: Center for Plant Molecular Biology, University of Tübingen, 72076 Tübingen, Germany.
authors.forename: Angela
authors.initials: A
authors.lastname: Brüx
authors.forename: Tzu-Yin
authors.initials: TY
authors.lastname: Liu
authors.forename: Melanie
authors.initials: M
authors.lastname: Krebs
authors.forename: York-Dieter
authors.initials: YD
authors.lastname: Stierhof
authors.forename: Jan U
authors.initials: JU
authors.lastname: Lohmann
authors.forename: Otto
authors.initials: O
authors.lastname: Miersch
authors.forename: Claus
authors.initials: C
authors.lastname: Wasternack
authors.forename: Karin
authors.initials: K
authors.lastname: Schumacher
mesh_terms: D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics / Q000254:growth & development*; D002482:Cellulose / Q000096:biosynthesis; D005030:Ethylenes / Q000378:metabolism; D020869:Gene Expression Profiling; D006056:Golgi Apparatus / Q000201:enzymology*; D018546:Hypocotyl / Q000201:enzymology / Q000254:growth & development*; D046529:Microscopy, Electron, Transmission; D054883:Oxylipins / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D025262:Vacuolar Proton-Translocating ATPases / Q000378:metabolism*
chemical_list: D005030:Ethylenes; D054883:Oxylipins; D002482:Cellulose; C036216:ethylene; D025262:Vacuolar Proton-Translocating ATPases