The Vacuolar Na+/H+ Antiporter Gene SsNHX1 from the Halophyte Salsola soda Confers Salt Tolerance in Transgenic Alfalfa (Medicago sativa L.)

Abstract

A putative vacuolar Na + /H + antiporter gene (SsNHX1) was isolated from the halophyte Salsola soda using the rapid amplification of cDNA ends method. Highly conserved regions of plant vacuolar Na + /H + antiporter, including amiloride-binding domain, NHE (Na + /H + exchange) domain, and 12 transmembrane segments, were found in the deduced amino acid sequence of SsNHX1. Multiple alignments of vacuolar Na + /H + antiporters showed that SsNHX1 shared high identity with other plant vacuolar Na + /H + antiporters. Phylogenetic relationship analysis indicated that SsNHX1 was clustered into the vacuolar Na + /H + antiporter group. Taken together, these results suggest that SsNHX1 is a new member of the vacuolar Na + /H + antiporter family. The effective expression of SsNHX1 in alfalfa (Medicago sativa L.) enhanced the salt tolerance of transgenic alfalfa which could grow in high concentrations of NaCl (up to 400 mM) over 50 days. This was the highest level of salt tolerance reported in transgenic plants. A further analysis of the physiological characteristics of transgenic and wild-type plants, including the Na + and K + contents, superoxide dismutase activity, the rate of electrolyte leakage, and the proline content, showed that large amounts of Na + in the cytoplasm of leaves were transported into vacuoles by the exogenous Na + /H + antiporter, which averted the toxic effects of Na + to the cell of transgenic alfalfa.

Co-expression of the Arabidopsis SOS genes enhances salt tolerance in transgenic tall fescue (Festuca arundinacea Schreb.)

“…The ROS accumulation leads to the instability of the cell membrane system and inhibits plant growth and development (Li et al 2011). The SOD, POD, and CAT are the important antioxidation enzymes for decreasing ROS harm and maintaining the integrity of the cellular membrane construction (Li et al 2011). In this report, we assayed the changes of physiological characteristics including SOD, POD, and CAT activity and content of MDA and Pro.…”

Salinity-Induced Effects in the Halophyte Suaeda salsa Using NMR-based Metabolomics

“…Soil salinity is an adverse environmental constraint that can reduce plant productivity and limit the utilization of agriculture land globally (Munns 2005;Dendooven et al 2010;Sonjak et al 2009;Li et al 2011;Yang et al 2011;Basyuni et al 2011;Xu et al 2011;Zhou et al 2011;Jellouli et al 2011). As estimated, approximately 80 million ha of cultivated land has been affected by soil salinity (Munns 2002;Askari et al 2006;Cui et al 2008).…”

Establishment of an efficient alfalfa regeneration system via organogenesis and the co-expression of Arabidopsis SOS genes improves salt tolerance in transgenic alfalfa (Medicago sativa L.)

“…Our findings indicated that the co-expression of Arabidopsis SOS genes and the SCaBP8 gene could maintain Na + homeostasis and improve salt tolerance in transgenic alfalfa, and the Bar gene could improve the herbicide resistance of the transgenic plants. The SOD, POD, and CAT were the important antioxidation enzymes for decreasing ROS harm and maintaining the integrity of the cellular membrane construction (Li et al 2011). In our report, the SOD, POD, and CAT activities and Pro content of wild-type were inferior to transgenic alfalfa, but the MDA content was higher than transgenic alfalfa.…”