@article{ZhuShabalaCuinetal.2016,
  author    = {Zhu, Min and Shabala, Lana and Cuin, Tracey A and Huang, Xin and Zhou, Meixue and Munns, Rana and Shabala, Sergey},
  title     = {Nax loci affect SOS1-like Na\(^{+}\)/H\(^{+}\) exchanger expression and activity in wheat},
  series = {Journal of Experimental Botany},
  volume    = {67},
  journal   = {Journal of Experimental Botany},
  number    = {3},
  doi       = {10.1093/jxb/erv493},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-150236},
  pages     = {835-844},
  year      = {2016},
  abstract  = {Salinity stress tolerance in durum wheat is strongly associated with a plant's ability to control Na\(^{+}\) delivery to the shoot. Two loci, termed Nax1 and Nax2, were recently identified as being critical for this process and the sodium transporters HKT1;4 and HKT1;5 were identified as the respective candidate genes. These transporters retrieve Na\(^{+}\) from the xylem, thus limiting the rates of Na\(^{+}\) transport from the root to the shoot. In this work, we show that the Nax loci also affect activity and expression levels of the SOS1-like Na\(^{+}\)/H\(^{+}\) exchanger in both root cortical and stelar tissues. Net Na\(^{+}\) efflux measured in isolated steles from salt-treated plants, using the non-invasive ion flux measuring MIFE technique, decreased in the sequence: Tamaroi (parental line)>Nax1=Nax2>Nax1:Nax2 lines. This efflux was sensitive to amiloride (a known inhibitor of the Na\(^{+}\)/H\(^{+}\) exchanger) and was mirrored by net H\(^{+}\) flux changes. TdSOS1 relative transcript levels were 6-10-fold lower in Nax lines compared with Tamaroi. Thus, it appears that Nax loci confer two highly complementary mechanisms, both of which contribute towards reducing the xylem Na\(^{+}\) content. One enhances the retrieval of Na\(^{+}\) back into the root stele via HKT1;4 or HKT1;5, whilst the other reduces the rate of Na\(^{+}\) loading into the xylem via SOS1. It is suggested that such duality plays an important adaptive role with greater versatility for responding to a changing environment and controlling Na\(^{+}\) delivery to the shoot.},
  language  = {en}
}