@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{LuDreyerDickinsonetal.2023,
  author    = {Lu, Jinping and Dreyer, Ingo and Dickinson, Miles Sasha and Panzer, Sabine and Jaślan, Dawid and Navarro-Retamal, Carlos and Geiger, Dietmar and Terpitz, Ulrich and Becker, Dirk and Stroud, Robert M. and Marten, Irene and Hedrich, Rainer},
  title     = {Vicia faba SV channel VfTPC1 is a hyperexcitable variant of plant vacuole two pore channels},
  series = {eLife},
  volume    = {12},
  journal   = {eLife},
  doi       = {10.7554/eLife.86384},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-350264},
  year      = {2023},
  abstract  = {To fire action-potential-like electrical signals, the vacuole membrane requires the two-pore channel TPC1, formerly called SV channel. The TPC1/SV channel functions as a depolarization-stimulated, non-selective cation channel that is inhibited by luminal Ca\(^{2+}\). In our search for species-dependent functional TPC1 channel variants with different luminal Ca\(^{2+}\) sensitivity, we found in total three acidic residues present in Ca\(^{2+}\) sensor sites 2 and 3 of the Ca\(^{2+}\)-sensitive AtTPC1 channel from Arabidopsis thaliana that were neutral in its Vicia faba ortholog and also in those of many other Fabaceae. When expressed in the Arabidopsis AtTPC1-loss-of-function background, wild-type VfTPC1 was hypersensitive to vacuole depolarization and only weakly sensitive to blocking luminal Ca\(^{2+}\). When AtTPC1 was mutated for these VfTPC1-homologous polymorphic residues, two neutral substitutions in Ca\(^{2+}\) sensor site 3 alone were already sufficient for the Arabidopsis At-VfTPC1 channel mutant to gain VfTPC1-like voltage and luminal Ca\(^{2+}\) sensitivity that together rendered vacuoles hyperexcitable. Thus, natural TPC1 channel variants exist in plant families which may fine-tune vacuole excitability and adapt it to environmental settings of the particular ecological niche.},
  language  = {en}
}
@article{JaślanDreyerLuetal.2019,
  author    = {Jaślan, Dawid and Dreyer, Ingo and Lu, Jinping and O'Malley, Ronan and Dindas, Julian and Marten, Irene and Hedrich, Rainer},
  title     = {Voltage-dependent gating of SV channel TPC1 confers vacuole excitability},
  series = {Nature Communications},
  volume    = {10},
  journal   = {Nature Communications},
  doi       = {10.1038/s41467-019-10599-x},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-202029},
  pages     = {2659},
  year      = {2019},
  abstract  = {In contrast to the plasma membrane, the vacuole membrane has not yet been associated with electrical excitation of plants. Here, we show that mesophyll vacuoles from Arabidopsis sense and control the membrane potential essentially via the K\(^+\)-permeable TPC1 and TPK channels. Electrical stimuli elicit transient depolarization of the vacuole membrane that can last for seconds. Electrical excitability is suppressed by increased vacuolar Ca\(^{2+}\) levels. In comparison to wild type, vacuoles from the fou2 mutant, harboring TPC1 channels insensitive to luminal Ca\(^{2+}\), can be excited fully by even weak electrical stimuli. The TPC1-loss-of-function mutant tpc1-2 does not respond to electrical stimulation at all, and the loss of TPK1/TPK3-mediated K\(^{+}\) transport affects the duration of TPC1-dependent membrane depolarization. In combination with mathematical modeling, these results show that the vacuolar K\(^+\)-conducting TPC1 and TPK1/TPK3 channels act in concert to provide for Ca\(^{2+}\)- and voltage-induced electrical excitability to the central organelle of plant cells.},
  language  = {en}
}