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Overexpression of a poplar two-pore K channel enhances salinity tolerance in tobacco cells.
- Source :
- Plant Cell, Tissue & Organ Culture; Jan2013, Vol. 112 Issue 1, p19-31, 13p
- Publication Year :
- 2013
-
Abstract
- Populus euphratica is a plant model intensively studied for elucidating physiological and molecular mechanisms of salt tolerance in woody species. Several studies have shown that vacuolar potassium (K) ion channels of the two-pore K (TPK) family play an important role in maintaining K homeostasis. Here, we cloned a putative TPK channel gene from P. euphratica, termed PeTPK. Sequence analysis of PeTPK1 identified the universal K-channel-specific pore signature, TXGYGD. Over-expression of PeTPK1 in tobacco BY-2 cells improved salt tolerance, but did not enhance tolerance to hyperosmotic stress caused by mannitol (200-600 mM). After 3 weeks of NaCl stress (100 and 150 mM), PeTPK1-transgenic cells had higher fresh and dry weights than wild-type cells. Salt treatment caused significantly higher Na accumulation and K loss in wild-type cells compared to transgenic cells. During short-term salt stress (100 mM NaCl, 24-h), PeTPK1-transgenic cells showed higher cell viability and reduced membrane permeabilization compared to wild-type cells. Scanning ion-selective electrode data revealed that salt-shock elicited a significantly higher transient K efflux from PeTPK1-transgenic callus cells and protoplasts compared to that observed in wild-type cells and protoplasts. We concluded that salt tolerance in P. euphratica is most likely mediated through PeTPK1. We propose that, under salt stress, PeTPK1 functions as an outward-rectifying, K efflux channel in the vacuole that transfers K to the cytosol to maintain K homeostasis. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 01676857
- Volume :
- 112
- Issue :
- 1
- Database :
- Complementary Index
- Journal :
- Plant Cell, Tissue & Organ Culture
- Publication Type :
- Academic Journal
- Accession number :
- 84364580
- Full Text :
- https://doi.org/10.1007/s11240-012-0207-9