Hyperactive mutant of a wheat plasma membrane Na+/H+ antiporter improves the growth and salt tolerance of transgenic tobacco

Plant Sci. 2016 Dec:253:176-186. doi: 10.1016/j.plantsci.2016.09.016. Epub 2016 Sep 29.

Abstract

Wheat SOS1 (TaSOS1) activity could be relieved upon deletion of the C-terminal 168 residues (the auto-inhibitory domain). This truncated form of wheat SOS1 (TaSOS1-974) was shown to increase compensation (compared to wild-type TaSOS1) for the salt sensitivity of a yeast mutant strain, AXT3K, via increased Na+ transportation out of cells during salinity stress. Expression of the plasma membrane proteins TaSOS1-974 or TaSOS1 improved the growth of transgenic tobacco plants compared with wild-type plants under normal conditions. However, plants expressing TaSOS1-974 grew better than TaSOS1-transformed plants. Upon salinity stress, Na+ efflux and K+ influx rates in the roots of transgenic plants expressing TaSOS1-974 or TaSOS1 were greater than those of wild-type plants. Furthermore, compared to TaSOS1-transgenic plants, TaSOS1-974-expressing roots showed faster Na+ efflux and K+ influx, resulting in less Na+ and more K+ accumulation in TaSOS1-974-transgenic plants compared to TaSOS1-transgenic and wild-type plants. TaSOS1-974-expressing plants had the lowest MDA content and electrolyte leakage among all tested plants, indicating that TaSOS1-974 might protect the plasma membrane against oxidative damage generated by salt stress. Overall, TaSOS1-974 conferred higher salt tolerance in transgenic plants compared to TaSOS1. Consistent with this result, transgenic plants expressing TaSOS1-974 showed a better growth performance than TaSOS1-expressing and wild-type plants under saline conditions.

Keywords: Auto-inhibitory domain; Plasma membrane Na(+)/H(+) antiporter; Salt tolerance; Transgenic tobacco; Wheat.

MeSH terms

  • Malondialdehyde / metabolism
  • Nicotiana / growth & development
  • Nicotiana / metabolism*
  • Plant Roots / metabolism
  • Plants, Genetically Modified / growth & development
  • Plants, Genetically Modified / metabolism*
  • Potassium / metabolism
  • Salinity
  • Salt Tolerance / genetics*
  • Sodium-Hydrogen Exchangers / genetics*
  • Sodium-Hydrogen Exchangers / metabolism
  • Triticum / genetics*

Substances

  • Sodium-Hydrogen Exchangers
  • Malondialdehyde
  • Potassium