TY  - JOUR
A1  - Bazihizina, Nadia
A1  - Böhm, Jennifer
A1  - Messerer, Maxim
A1  - Stigloher, Christian
A1  - Müller, Heike M.
A1  - Cuin, Tracey Ann
A1  - Maierhofer, Tobias
A1  - Cabot, Joan
A1  - Mayer, Klaus F. X.
A1  - Fella, Christian
A1  - Huang, Shouguang
A1  - Al‐Rasheid, Khaled A. S.
A1  - Alquraishi, Saleh
A1  - Breadmore, Michael
A1  - Mancuso, Stefano
A1  - Shabala, Sergey
A1  - Ache, Peter
A1  - Zhang, Heng
A1  - Zhu, Jian‐Kang
A1  - Hedrich, Rainer
A1  - Scherzer, Sönke
T1  - Stalk cell polar ion transport provide for bladder‐based salinity tolerance in Chenopodium quinoa
JF  - New Phytologist
N2  - Chenopodium quinoa uses epidermal bladder cells (EBCs) to sequester excess salt. Each EBC complex consists of a leaf epidermal cell, a stalk cell, and the bladder.

Under salt stress, sodium (Na\(^{+}\)), chloride (Cl\(^{−}\)), potassium (K\(^{+}\)) and various metabolites are shuttled from the leaf lamina to the bladders. Stalk cells operate as both a selectivity filter and a flux controller.

In line with the nature of a transfer cell, advanced transmission electron tomography, electrophysiology, and fluorescent tracer flux studies revealed the stalk cell’s polar organization and bladder‐directed solute flow.

RNA sequencing and cluster analysis revealed the gene expression profiles of the stalk cells. Among the stalk cell enriched genes, ion channels and carriers as well as sugar transporters were most pronounced. Based on their electrophysiological fingerprint and thermodynamic considerations, a model for stalk cell transcellular transport was derived.
KW  - halophyte
KW  - polar ion transport
KW  - quinoa
KW  - salt tolerance
KW  - stalk cell
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-287222
VL  - 235
IS  - 5
SP  - 1822
EP  - 1835
ER  - 
TY  - JOUR
A1  - Zhu, Min
A1  - Shabala, Lana
A1  - Cuin, Tracey A
A1  - Huang, Xin
A1  - Zhou, Meixue
A1  - Munns, Rana
A1  - Shabala, Sergey
T1  - Nax loci affect SOS1-like Na\(^{+}\)/H\(^{+}\) exchanger expression and activity in wheat
JF  - Journal of Experimental Botany
N2  - 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.
KW  - HKT transporter
KW  - potassium
KW  - salinity stress
KW  - sequestration
KW  - sodium
KW  - xylem loading
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-150236
VL  - 67
IS  - 3
ER  -