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Nax loci affect SOS1-like Na+/H+ exchanger expression and activity in wheat


Zhu, M and Shabala, L and Cuin, TA and Huang, X and Zhou, M and Munns, R and Shabala, S, Nax loci affect SOS1-like Na+/H+ exchanger expression and activity in wheat, Journal of Experimental Botany, 67, (3) pp. 835-844. ISSN 0022-0957 (2016) [Refereed Article]


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© The Author 2015. Licensed under Creative Commons Attribution 3.0 Unported (CC BY 3.0)

DOI: doi:10.1093/jxb/erv493


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.

Item Details

Item Type:Refereed Article
Keywords:wheat, salinity tolerance, HKT transporter, potassium, sequestration, sodium, xylem loading
Research Division:Agricultural, Veterinary and Food Sciences
Research Group:Crop and pasture production
Research Field:Crop and pasture improvement (incl. selection and breeding)
Objective Division:Plant Production and Plant Primary Products
Objective Group:Grains and seeds
Objective Field:Wheat
UTAS Author:Zhu, M (Ms Min Zhu)
UTAS Author:Shabala, L (Associate Professor Lana Shabala)
UTAS Author:Cuin, TA (Dr Tracey Cuin)
UTAS Author:Huang, X (Mr Xin Huang)
UTAS Author:Zhou, M (Professor Meixue Zhou)
UTAS Author:Shabala, S (Professor Sergey Shabala)
ID Code:106563
Year Published:2016
Web of Science® Times Cited:77
Deposited By:Tasmanian Institute of Agriculture
Deposited On:2016-02-14
Last Modified:2017-11-06
Downloads:170 View Download Statistics

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