TY  - JOUR
A1  - Lehmann, Julian
A1  - Jørgensen, Morten E.
A1  - Fratz, Stefanie
A1  - Müller, Heike M.
A1  - Kusch, Jana
A1  - Scherzer, Sönke
A1  - Navarro-Retamal, Carlos
A1  - Mayer, Dominik
A1  - Böhm, Jennifer
A1  - Konrad, Kai R.
A1  - Terpitz, Ulrich
A1  - Dreyer, Ingo
A1  - Mueller, Thomas D.
A1  - Sauer, Markus
A1  - Hedrich, Rainer
A1  - Geiger, Dietmar
A1  - Maierhofer, Tobias
T1  - Acidosis-induced activation of anion channel SLAH3 in the flooding-related stress response of Arabidopsis
JF  - Current Biology
N2  - Plants, as sessile organisms, gained the ability to sense and respond to biotic and abiotic stressors to survive severe changes in their environments. The change in our climate comes with extreme dry periods but also episodes of flooding. The latter stress condition causes anaerobiosis-triggered cytosolic acidosis and impairs plant function. The molecular mechanism that enables plant cells to sense acidity and convey this signal via membrane depolarization was previously unknown. Here, we show that acidosis-induced anion efflux from Arabidopsis (Arabidopsis thaliana) roots is dependent on the S-type anion channel AtSLAH3. Heterologous expression of SLAH3 in Xenopus oocytes revealed that the anion channel is directly activated by a small, physiological drop in cytosolic pH. Acidosis-triggered activation of SLAH3 is mediated by protonation of histidine 330 and 454. Super-resolution microscopy analysis showed that the increase in cellular proton concentration switches SLAH3 from an electrically silent channel dimer into its active monomeric form. Our results show that, upon acidification, protons directly switch SLAH3 to its open configuration, bypassing kinase-dependent activation. Moreover, under flooding conditions, the stress response of Arabidopsis wild-type (WT) plants was significantly higher compared to SLAH3 loss-of-function mutants. Our genetic evidence of SLAH3 pH sensor function may guide the development of crop varieties with improved stress tolerance.
KW  - SLAH3
KW  - S-type anion channel
KW  - hypoxia
KW  - pH
KW  - cytosolic acidification
KW  - flooding
KW  - PALM
KW  - stoichiometry
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-363320
VL  - 31
ER  - 
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  -