title: The plant cytoskeleton controls regulatory volume increase.
abstract: The ability to adjust cell volume is required for the adaptation to osmotic stress. Plant protoplasts can swell within seconds in response to hypoosmotic shock suggesting that membrane material is released from internal stores. Since the stability of plant membranes depends on submembraneous actin, we asked, whether this regulatory volume control depends on the cytoskeleton. As system we used two cell lines from grapevine which differ in their osmotic tolerance and observed that the cytoskeleton responded differently in these two cell lines. To quantify the ability for regulatory volume control, we used hydraulic conductivity (Lp) as readout and demonstrated a role of the cytoskeleton in protoplast swelling. Chelation of calcium, inhibition of calcium channels, or manipulation of membrane fluidity, did not significantly alter Lp, whereas direct manipulation of the cytoskeleton via specific chemical reagents, or indirectly, through the bacterial elicitor Harpin or activation of phospholipase D, was effective. By optochemical engineering of actin using a caged form of the phytohormone auxin we can break the symmetry of actin organisation resulting in a localised deformation of cell shape indicative of a locally increased Lp. We interpret our findings in terms of a model, where the submembraneous cytoskeleton controls the release of intracellular membrane stores during regulatory volume change.
authors: Molecular Cell Biology, Botanical Institute, Karlsruhe Institute of Technology, Kaiserstr. 2, 76128 Karlsruhe, Germany. liuqionglandmail@gmail.com
authors: Qiong
authors: Q
authors: Liu
authors: Fei
authors: F
authors: Qiao
authors: Ahmed
authors: A
authors: Ismail
authors: Xiaoli
authors: X
authors: Chang
authors: Peter
authors: P
authors: Nick
mesh_terms: D000199:Actins / Q000737:chemistry* / Q000378:metabolism; D019905:Benzyl Alcohol / Q000494:pharmacology; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000378:metabolism; D048430:Cell Shape / Q000187:drug effects; D048429:Cell Size / Q000187:drug effects; D002478:Cells, Cultured; D003599:Cytoskeleton / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D004789:Enzyme Activation; D007210:Indoleacetic Acids / Q000737:chemistry / Q000378:metabolism; D009995:Osmosis; D017239:Paclitaxel / Q000494:pharmacology; D010739:Phospholipase D / Q000378:metabolism; D059828:Plant Cells / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D011523:Protoplasts / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D053778:Thiazolidines / Q000494:pharmacology; D027843:Vitis / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D014882:Water-Electrolyte Balance / Q000502:physiology
chemical_list: D000199:Actins; D019086:Bridged Bicyclo Compounds, Heterocyclic; D015220:Calcium Channels; D007210:Indoleacetic Acids; D053778:Thiazolidines; D010739:Phospholipase D; D019905:Benzyl Alcohol; C037068:latrunculin B; D017239:Paclitaxel; D002118:Calcium
keywords: Cytoskeleton; L(p); Osmotic expansion; Protoplast; Regulatory cell volume control; Vitis; hydraulic conductivity