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Mechanisms underlying turgor regulation in the estuarine alga Vaucheria erythrospora (Xanthophyceae) exposed to hyperosmotic shock


Muralidhar, A and Shabala, L and Broady, P and Shabala, S and Garrill, A, Mechanisms underlying turgor regulation in the estuarine alga Vaucheria erythrospora (Xanthophyceae) exposed to hyperosmotic shock, Plant, Cell and Environment, 38, (8) pp. 1514-1527. ISSN 0140-7791 (2015) [Refereed Article]

Copyright Statement

2014 John Wiley & Sons Ltd

DOI: doi:10.1111/pce.12503


Aquatic organisms are often exposed to dramatic changes in salinity in the environment. Despite decades of research, many questions related to molecular and physiological mechanisms mediating sensing and adaptation to salinity stress remain unanswered. Here, responses of Vaucheria erythrospora, a turgor-regulating xanthophycean alga from an estuarine habitat, have been investigated. The role of ion uptake in turgor regulation was studied using a single cell pressure probe, microelectrode ion flux estimation (MIFE) technique and membrane potential (Em) measurements. Turgor recovery was inhibited by Gd3+, tetraethylammonium chloride (TEA), verapamil and orthovanadate. A NaCl-induced shock rapidly depolarized the plasma membrane while an isotonic sorbitol treatment hyperpolarized it. Turgor recovery was critically dependent on the presence of Na+ but not K+ and Cl in the incubation media. Na+ uptake was strongly decreased by amiloride and changes in net Na+ and H+ fluxes were oppositely directed. This suggests active uptake of Na+ in V. erythrospora mediated by an antiport Na+/H+ system, functioning in the direction opposite to that of the SOS1 exchanger in higher plants. The alga also retains K+ efficiently when exposed to high NaCl concentrations. Overall, this study provides insights into mechanisms enabling V. erythrospora to regulate turgor via ion movements during hyperosmotic stress.

Item Details

Item Type:Refereed Article
Keywords:Stramenopila, Vaucheria, membrane potential, Na+/H+ exchanger, Na+ and K+ fluxes, pressure probe
Research Division:Biological Sciences
Research Group:Plant biology
Research Field:Phycology (incl. marine grasses)
Objective Division:Plant Production and Plant Primary Products
Objective Group:Other plant production and plant primary products
Objective Field:Other plant production and plant primary products not elsewhere classified
UTAS Author:Shabala, L (Associate Professor Lana Shabala)
UTAS Author:Shabala, S (Professor Sergey Shabala)
ID Code:100724
Year Published:2015
Web of Science® Times Cited:4
Deposited By:Tasmanian Institute of Agriculture
Deposited On:2015-05-27
Last Modified:2017-11-02

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