@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} } @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-190908}, 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} } @article{GrausLiRathjeetal.2023, author = {Graus, Dorothea and Li, Kunkun and Rathje, Jan M. and Ding, Meiqi and Krischke, Markus and M{\"u}ller, Martin J. and Cuin, Tracey Ann and Al-Rasheid, Khaled A. S. and Scherzer, S{\"o}nke and Marten, Irene and Konrad, Kai R. and Hedrich, Rainer}, title = {Tobacco leaf tissue rapidly detoxifies direct salt loads without activation of calcium and SOS signaling}, series = {New Phytologist}, volume = {237}, journal = {New Phytologist}, number = {1}, doi = {10.1111/nph.18501}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-312152}, pages = {217 -- 231}, year = {2023}, abstract = {Salt stress is a major abiotic stress, responsible for declining agricultural productivity. Roots are regarded as hubs for salt detoxification, however, leaf salt concentrations may exceed those of roots. How mature leaves manage acute sodium chloride (NaCl) stress is mostly unknown. To analyze the mechanisms for NaCl redistribution in leaves, salt was infiltrated into intact tobacco leaves. It initiated pronounced osmotically-driven leaf movements. Leaf downward movement caused by hydro-passive turgor loss reached a maximum within 2 h. Salt-driven cellular water release was accompanied by a transient change in membrane depolarization but not an increase in cytosolic calcium ion (Ca\(^{2+}\)) level. Nonetheless, only half an hour later, the leaves had completely regained turgor. This recovery phase was characterized by an increase in mesophyll cell plasma membrane hydrogen ion (H\(^{+}\)) pumping, a salt uptake-dependent cytosolic alkalization, and a return of the apoplast osmolality to pre-stress levels. Although, transcript numbers of abscisic acid- and Salt Overly Sensitive pathway elements remained unchanged, salt adaptation depended on the vacuolar H\(^{+}\)/Na\(^{+}\)-exchanger NHX1. Altogether, tobacco leaves can detoxify sodium ions (Na\(^{+}\)) rapidly even under massive salt loads, based on pre-established posttranslational settings and NHX1 cation/H+ antiport activity. Unlike roots, signaling and processing of salt stress in tobacco leaves does not depend on Ca\(^{2+}\) signaling.}, language = {en} } @article{BazihizinaBoehmMessereretal.2022, author = {Bazihizina, Nadia and B{\"o}hm, Jennifer and Messerer, Maxim and Stigloher, Christian and M{\"u}ller, Heike M. and Cuin, Tracey Ann and Maierhofer, Tobias and Cabot, Joan and Mayer, Klaus F. X. and Fella, Christian and Huang, Shouguang and Al-Rasheid, Khaled A. S. and Alquraishi, Saleh and Breadmore, Michael and Mancuso, Stefano and Shabala, Sergey and Ache, Peter and Zhang, Heng and Zhu, Jian-Kang and Hedrich, Rainer and Scherzer, S{\"o}nke}, title = {Stalk cell polar ion transport provide for bladder-based salinity tolerance in Chenopodium quinoa}, series = {New Phytologist}, volume = {235}, journal = {New Phytologist}, number = {5}, doi = {10.1111/nph.18205}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-287222}, pages = {1822 -- 1835}, year = {2022}, abstract = {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.}, language = {en} }