SOS2 Promotes Salt Tolerance in Part by Interacting with the Vacuolar H+-ATPase and Upregulating Its Transport Activity
Open Access
- 1 November 2007
- journal article
- research article
- Published by Taylor & Francis Ltd in Molecular and Cellular Biology
- Vol. 27 (22), 7781-7790
- https://doi.org/10.1128/mcb.00430-07
Abstract
The salt overly sensitive (SOS) pathway is critical for plant salt stress tolerance and has a key role in regulating ion transport under salt stress. To further investigate salt tolerance factors regulated by the SOS pathway, we expressed an N-terminal fusion of the improved tandem affinity purification tag to SOS2 (NTAP-SOS2) in sos2-2 mutant plants. Expression of NTAP-SOS2 rescued the salt tolerance defect of sos2-2 plants, indicating that the fusion protein was functional in vivo. Tandem affinity purification of NTAP-SOS2-containing protein complexes and subsequent liquid chromatography-tandem mass spectrometry analysis indicated that subunits A, B, C, E, and G of the peripheral cytoplasmic domain of the vacuolar H+-ATPase (V-ATPase) were present in a SOS2-containing protein complex. Parallel purification of samples from control and salt-stressed NTAP-SOS2/sos2-2 plants demonstrated that each of these V-ATPase subunits was more abundant in NTAP-SOS2 complexes isolated from salt-stressed plants, suggesting that the interaction may be enhanced by salt stress. Yeast two-hybrid analysis showed that SOS2 interacted directly with V-ATPase regulatory subunits B1 and B2. The importance of the SOS2 interaction with the V-ATPase was shown at the cellular level by reduced H+ transport activity of tonoplast vesicles isolated from sos2-2 cells relative to vesicles from wild-type cells. In addition, seedlings of the det3 mutant, which has reduced V-ATPase activity, were found to be severely salt sensitive. Our results suggest that regulation of V-ATPase activity is an additional key function of SOS2 in coordinating changes in ion transport during salt stress and in promoting salt tolerance.This publication has 70 references indexed in Scilit:
- SCABP8/CBL10, a Putative Calcium Sensor, Interacts with the Protein Kinase SOS2 to Protect Arabidopsis Shoots from Salt StressPlant Cell, 2007
- The plasma membrane Na + /H + antiporter SOS1 interacts with RCD1 and functions in oxidative stress tolerance in ArabidopsisProceedings of the National Academy of Sciences of the United States of America, 2006
- A pathogen-inducible endogenous siRNA in plant immunityProceedings of the National Academy of Sciences of the United States of America, 2006
- Regulatory Functions of Nuclear Hexokinase1 Complex in Glucose SignalingCell, 2006
- A WNK kinase binds and phosphorylates V‐ATPase subunit CFEBS Letters, 2006
- Vacuolar cation/H+ exchange, ion homeostasis, and leaf development are altered in a T‐DNA insertional mutant of AtNHX1, the Arabidopsis vacuolar Na+/H+ antiporterThe Plant Journal, 2003
- SALT AND DROUGHT STRESS SIGNAL TRANSDUCTION IN PLANTSAnnual Review of Plant Biology, 2002
- Dynamics of activity and structure of the tonoplast vacuolar-type H+-ATPase in plants with differing CAM expression and in a C3 plant under salt stressProtoplasma, 1997
- In suspension-culturedDaucus carotacells salt stress stimulates H+-transport but not ATP hydrolysis of the V-ATPaseJournal of Experimental Botany, 1996
- Salt regulation of transcript levels for the c subunit of a leaf vacuolar H+-ATPase in the halophyte Mesembryanthemum crystallinumThe Plant Journal, 1996