SOS1 gene overexpression increased salt tolerance in transgenic tobacco by maintaining a higher K+/Na+ ratio

Crop productivity is greatly affected by soil salinity, so improvement in salinity tolerance of crops is a major objective of many studies. We overexpressed the Arabidopsis thaliana SOS1 gene, which encodes a plasma membrane Na+/H+ antiporter, in tobacco (Nicotiana tabacum cv. Xanthi-nc). Compared with non-transgenic plants, seeds from transgenic tobacco had better germination under 120 mM (mmol L-1) NaCl stress; chlorophyll loss in the transgenic seedlings treated with 360 mM NaCl was less; transgenic tobacco showed superior growth after irrigation with NaCl solutions: and transgenic seedlings with 150 mM NaCl stress accumulated less Na+ and more K+. In addition, roots of SOS1-overexpressing seedlings lost less K+ instantaneously in response to 50 mM NaCl than control plants. These results showed that the A. thaliana SOS1 gene potentially can improve the salt tolerance of other plant species. (C) 2011 Elsevier GmbH. All rights reserved.