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 - Bemm, Felix A1 - Becker, Dirk A1 - Larisch, Christina A1 - Kreuzer, Ines A1 - Escalante-Perez, Maria A1 - Schulze, Waltraud X. A1 - Ankenbrand, Markus A1 - Van de Weyer, Anna-Lena A1 - Krol, Elzbieta A1 - Al-Rasheid, Khaled A. A1 - Mithöfer, Axel A1 - Weber, Andreas P. A1 - Schultz, Jörg A1 - Hedrich, Rainer T1 - Venus flytrap carnivorous lifestyle builds on herbivore defense strategies JF - Genome Research N2 - Although the concept of botanical carnivory has been known since Darwin's time, the molecular mechanisms that allow animal feeding remain unknown, primarily due to a complete lack of genomic information. Here, we show that the transcriptomic landscape of the Dionaea trap is dramatically shifted toward signal transduction and nutrient transport upon insect feeding, with touch hormone signaling and protein secretion prevailing. At the same time, a massive induction of general defense responses is accompanied by the repression of cell death-related genes/processes. We hypothesize that the carnivory syndrome of Dionaea evolved by exaptation of ancient defense pathways, replacing cell death with nutrient acquisition. KW - Dionaea-muscipula ellis KW - Plant utricularia-gibba KW - Programmed cell-death KW - Genomics data sets KW - RNA-SEQ data KW - Arabidopsis-thaliana KW - Jasmonate perception KW - Action potentials KW - Stress responses KW - Wonderful plants Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-188799 VL - 26 IS - 6 ER - TY - JOUR A1 - Deeken, Rosalia A1 - Gohlke, Jochen A1 - Scholz, Claus-Juergen A1 - Kneitz, Susanne A1 - Weber, Dana A1 - Fuchs, Joerg A1 - Hedrich, Rainer T1 - DNA Methylation Mediated Control of Gene Expression Is Critical for Development of Crown Gall Tumors JF - PLoS Genetics N2 - Crown gall tumors develop after integration of the T-DNA of virulent Agrobacterium tumefaciens strains into the plant genome. Expression of the T-DNA–encoded oncogenes triggers proliferation and differentiation of transformed plant cells. Crown gall development is known to be accompanied by global changes in transcription, metabolite levels, and physiological processes. High levels of abscisic acid (ABA) in crown galls regulate expression of drought stress responsive genes and mediate drought stress acclimation, which is essential for wild-type-like tumor growth. An impact of epigenetic processes such as DNA methylation on crown gall development has been suggested; however, it has not yet been investigated comprehensively. In this study, the methylation pattern of Arabidopsis thaliana crown galls was analyzed on a genome-wide scale as well as at the single gene level. Bisulfite sequencing analysis revealed that the oncogenes Ipt, IaaH, and IaaM were unmethylated in crown galls. Nevertheless, the oncogenes were susceptible to siRNA–mediated methylation, which inhibited their expression and subsequently crown gall growth. Genome arrays, hybridized with methylated DNA obtained by immunoprecipitation, revealed a globally hypermethylated crown gall genome, while promoters were rather hypomethylated. Mutants with reduced non-CG methylation developed larger tumors than the wild-type controls, indicating that hypermethylation inhibits plant tumor growth. The differential methylation pattern of crown galls and the stem tissue from which they originate correlated with transcriptional changes. Genes known to be transcriptionally inhibited by ABA and methylated in crown galls became promoter methylated upon treatment of A. thaliana with ABA. This suggests that the high ABA levels in crown galls may mediate DNA methylation and regulate expression of genes involved in drought stress protection. In summary, our studies provide evidence that epigenetic processes regulate gene expression, physiological processes, and the development of crown gall tumors. KW - DNA methylation KW - DNA transcription KW - gene expression KW - oncogenes KW - plant genomics KW - sequence motif analysis KW - arabidopsis thaliana KW - agrobacterium tumefaciens Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-96318 ER - TY - JOUR A1 - Du, Baoguo A1 - Ma, Yuhua A1 - Yáñez‐Serrano, Ana Maria A1 - Arab, Leila A1 - Fasbender, Lukas A1 - Alfarraj, Saleh A1 - Albasher, Gadah A1 - Hedrich, Rainer A1 - White, Philip J. A1 - Werner, Christiane A1 - Rennenberg, Heinz T1 - Physiological responses of date palm (Phoenix dactylifera) seedlings to seawater and flooding JF - New Phytologist N2 - In their natural environment along coast lines, date palms are exposed to seawater inundation and, hence, combined stress by salinity and flooding. To elucidate the consequences of this combined stress on foliar gas exchange and metabolite abundances in leaves and roots, date palm seedlings were exposed to flooding with seawater and its major constituents under controlled conditions. Seawater flooding significantly reduced CO\(_{2}\) assimilation, transpiration and stomatal conductance, but did not affect isoprene emission. A similar effect was observed upon NaCl exposure. By contrast, flooding with distilled water or MgSO\(_{4}\) did not affect CO\(_{2}\)/H\(_{2}\)O gas exchange or stomatal conductance significantly, indicating that neither flooding itself, nor seawater sulfate, contributed greatly to stomatal closure. Seawater exposure increased Na and Cl contents in leaves and roots, but did not affect sulfate contents significantly. Metabolite analyses revealed reduced abundances of foliar compatible solutes, such as sugars and sugar alcohols, whereas nitrogen compounds accumulated in roots. Reduced transpiration upon seawater exposure may contribute to controlling the movement of toxic ions to leaves and, therefore, can be seen as a mechanism to cope with salinity. The present results indicate that date palm seedlings are tolerant towards seawater exposure to some extent, and highly tolerant to flooding. KW - compatible solutes and other metabolites KW - date palm KW - flooding KW - salinity KW - shoot–root interaction KW - stomatal conductance KW - sulfate Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-228226 VL - 229 IS - 6 SP - 3318 EP - 3329 ER - TY - JOUR A1 - Graus, Dorothea A1 - Li, Kunkun A1 - Rathje, Jan M. A1 - Ding, Meiqi A1 - Krischke, Markus A1 - Müller, Martin J. A1 - Cuin, Tracey Ann A1 - Al‐Rasheid, Khaled A. S. A1 - Scherzer, Sönke A1 - Marten, Irene A1 - Konrad, Kai R. A1 - Hedrich, Rainer T1 - Tobacco leaf tissue rapidly detoxifies direct salt loads without activation of calcium and SOS signaling JF - New Phytologist N2 - 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. KW - calcium signaling KW - cytosolic pH KW - leaf response KW - NaCl transport KW - NHX1 KW - osmotic effects KW - Salt Overly Sensitive pathway KW - salt stress Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-312152 VL - 237 IS - 1 SP - 217 EP - 231 ER - TY - JOUR A1 - Jones, Jeffrey J. A1 - Huang, Shouguang A1 - Hedrich, Rainer A1 - Geilfus, Christoph‐Martin A1 - Roelfsema, M. Rob G. T1 - The green light gap: a window of opportunity for optogenetic control of stomatal movement JF - New Phytologist N2 - Green plants are equipped with photoreceptors that are capable of sensing radiation in the ultraviolet‐to‐blue and the red‐to‐far‐red parts of the light spectrum. However, plant cells are not particularly sensitive to green light (GL), and light which lies within this part of the spectrum does not efficiently trigger the opening of stomatal pores. Here, we discuss the current knowledge of stomatal responses to light, which are either provoked via photosynthetically active radiation or by specific blue light (BL) signaling pathways. The limited impact of GL on stomatal movements provides a unique option to use this light quality to control optogenetic tools. Recently, several of these tools have been optimized for use in plant biological research, either to control gene expression, or to provoke ion fluxes. Initial studies with the BL‐activated potassium channel BLINK1 showed that this tool can speed up stomatal movements. Moreover, the GL‐sensitive anion channel GtACR1 can induce stomatal closure, even at conditions that provoke stomatal opening in wild‐type plants. Given that crop plants in controlled‐environment agriculture and horticulture are often cultivated with artificial light sources (i.e. a combination of blue and red light from light‐emitting diodes), GL signals can be used as a remote‐control signal that controls stomatal transpiration and water consumption. KW - anion channel KW - channelrhodopsin KW - Chl KW - guard cell KW - ion channel KW - light‐gated KW - membrane potential KW - phototropin Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-293724 VL - 236 IS - 4 SP - 1237 EP - 1244 ER - TY - JOUR A1 - Karimi, Sohail M. A1 - Freund, Matthias A1 - Wager, Brittney M. A1 - Knoblauch, Michael A1 - Fromm, Jörg A1 - M. Mueller, Heike A1 - Ache, Peter A1 - Krischke, Markus A1 - Mueller, Martin J. A1 - Müller, Tobias A1 - Dittrich, Marcus A1 - Geilfus, Christoph-Martin A1 - Alfaran, Ahmed H. A1 - Hedrich, Rainer A1 - Deeken, Rosalia T1 - Under salt stress guard cells rewire ion transport and abscisic acid signaling JF - New Phytologist N2 - Soil salinity is an increasingly global problem which hampers plant growth and crop yield. Plant productivity depends on optimal water-use efficiency and photosynthetic capacity balanced by stomatal conductance. Whether and how stomatal behavior contributes to salt sensitivity or tolerance is currently unknown. This work identifies guard cell-specific signaling networks exerted by a salt-sensitive and salt-tolerant plant under ionic and osmotic stress conditions accompanied by increasing NaCl loads. We challenged soil-grown Arabidopsis thaliana and Thellungiella salsuginea plants with short- and long-term salinity stress and monitored genome-wide gene expression and signals of guard cells that determine their function. Arabidopsis plants suffered from both salt regimes and showed reduced stomatal conductance while Thellungiella displayed no obvious stress symptoms. The salt-dependent gene expression changes of guard cells supported the ability of the halophyte to maintain high potassium to sodium ratios and to attenuate the abscisic acid (ABA) signaling pathway which the glycophyte kept activated despite fading ABA concentrations. Our study shows that salinity stress and even the different tolerances are manifested on a single cell level. Halophytic guard cells are less sensitive than glycophytic guard cells, providing opportunities to manipulate stomatal behavior and improve plant productivity. KW - soil KW - stomata KW - abscisic acid (ABA) KW - glycophyte Arabidopsis KW - guard cell KW - halophyte Thellungiella/Eutrema KW - ion transport KW - salt stress Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-259635 VL - 231 IS - 3 ER - TY - JOUR A1 - Li, Kunkun A1 - Prada, Juan A1 - Damineli, Daniel S. C. A1 - Liese, Anja A1 - Romeis, Tina A1 - Dandekar, Thomas A1 - Feijó, José A. A1 - Hedrich, Rainer A1 - Konrad, Kai Robert T1 - An optimized genetically encoded dual reporter for simultaneous ratio imaging of Ca\(^{2+}\) and H\(^{+}\) reveals new insights into ion signaling in plants JF - New Phytologist N2 - Whereas the role of calcium ions (Ca\(^{2+}\)) in plant signaling is well studied, the physiological significance of pH‐changes remains largely undefined. Here we developed CapHensor, an optimized dual‐reporter for simultaneous Ca\(^{2+}\) and pH ratio‐imaging and studied signaling events in pollen tubes (PTs), guard cells (GCs), and mesophyll cells (MCs). Monitoring spatio‐temporal relationships between membrane voltage, Ca\(^{2+}\)‐ and pH‐dynamics revealed interconnections previously not described. In tobacco PTs, we demonstrated Ca\(^{2+}\)‐dynamics lag behind pH‐dynamics during oscillatory growth, and pH correlates more with growth than Ca\(^{2+}\). In GCs, we demonstrated abscisic acid (ABA) to initiate stomatal closure via rapid cytosolic alkalization followed by Ca2+ elevation. Preventing the alkalization blocked GC ABA‐responses and even opened stomata in the presence of ABA, disclosing an important pH‐dependent GC signaling node. In MCs, a flg22‐induced membrane depolarization preceded Ca2+‐increases and cytosolic acidification by c. 2 min, suggesting a Ca\(^{2+}\)/pH‐independent early pathogen signaling step. Imaging Ca2+ and pH resolved similar cytosol and nuclear signals and demonstrated flg22, but not ABA and hydrogen peroxide to initiate rapid membrane voltage‐, Ca\(^{2+}\)‐ and pH‐responses. We propose close interrelation in Ca\(^{2+}\)‐ and pH‐signaling that is cell type‐ and stimulus‐specific and the pH having crucial roles in regulating PT growth and stomata movement. KW - abscisic acid (ABA) KW - calcium KW - flg22 KW - guard cells KW - imaging KW - ion signaling KW - pH KW - pollen tube Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-239847 VL - 230 IS - 6 SP - 2292 EP - 2310 ER - TY - JOUR A1 - Lu, Jinping A1 - Dreyer, Ingo A1 - Dickinson, Miles Sasha A1 - Panzer, Sabine A1 - Jaślan, Dawid A1 - Navarro-Retamal, Carlos A1 - Geiger, Dietmar A1 - Terpitz, Ulrich A1 - Becker, Dirk A1 - Stroud, Robert M. A1 - Marten, Irene A1 - Hedrich, Rainer T1 - Vicia faba SV channel VfTPC1 is a hyperexcitable variant of plant vacuole two pore channels JF - eLife N2 - 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. KW - A. thaliana KW - Brassicaceae KW - Fabaceae KW - pore KW - potassium channel KW - voltage gating KW - vacuolar calcium sensor Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-350264 VL - 12 ER -