ORCID Profile
0000-0003-3224-1362
Current Organisation
Julius-Maximilians-Universität Würzburg Biozentrum
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Plant Physiology | Plant Cell and Molecular Biology | Plant Biology | Crop and Pasture Biochemistry and Physiology | Ecology | Crop and Pasture Improvement (Selection and Breeding) | Ecological Physiology | Biological Adaptation
ANZSRC Socio-Economic Objective (SEO)
Expanding Knowledge in the Biological Sciences | Summer Grains and Oilseeds not elsewhere classified | Barley | Climate Change Adaptation Measures | Maize | Expanding Knowledge in the Agricultural and Veterinary Sciences | Forest and Woodlands Flora, Fauna and Biodiversity |
Related Links
Publications
Venus Flytrap HKT1-Type Channel Provides for Prey Sodium Uptake into Carnivorous Plant Without Conflicting with Electrical Excitability
Publisher: Elsevier BV
Date: 03-2016
The role of Arabidopsis ABA receptors from the PYR/PYL/RCAR family in stomatal acclimation and closure signal integration.
Publisher: Springer Science and Business Media LLC
Date: 26-08-2019
DOI: 10.1038/S41477-019-0490-0
Abstract: Stomata are microscopic pores found on the surfaces of leaves that act to control CO
Author response: Anion channel SLAH3 is a regulatory target of chitin receptor-associated kinase PBL27 in microbial stomatal closure
Publisher: eLife Sciences Publications, Ltd
Date: 05-09-2019
Epidermal bladder cells confer salinity stress tolerance in the halophyte quinoa and Atriplex species
Publisher: Wiley
Date: 18-07-2017
DOI: 10.1111/PCE.12995
Abstract: Epidermal bladder cells (EBCs) have been postulated to assist halophytes in coping with saline environments. However, little direct supporting evidence is available. Here, Chenopodium quinoa plants were grown under saline conditions for 5 weeks. One day prior to salinity treatment, EBCs from all leaves and petioles were gently removed by using a soft cosmetic brush and physiological, ionic and metabolic changes in brushed and non-brushed leaves were compared. Gentle removal of EBC neither initiated wound metabolism nor affected the physiology and biochemistry of control-grown plants but did have a pronounced effect on salt-grown plants, resulting in a salt-sensitive phenotype. Of 91 detected metabolites, more than half were significantly affected by salinity. Removal of EBC dramatically modified these metabolic changes, with the biggest differences reported for gamma-aminobutyric acid (GABA), proline, sucrose and inositol, affecting ion transport across cellular membranes (as shown in electrophysiological experiments). This work provides the first direct evidence for a role of EBC in salt tolerance in halophytes and attributes this to (1) a key role of EBC as a salt dump for external sequestration of sodium (2) improved K
GABA signalling modulates stomatal opening to enhance plant water use efficiency and drought resilience
Publisher: Springer Science and Business Media LLC
Date: 29-03-2021
DOI: 10.1038/S41467-021-21694-3
Abstract: The non-protein amino acid γ-aminobutyric acid (GABA) has been proposed to be an ancient messenger for cellular communication conserved across biological kingdoms. GABA has well-defined signalling roles in animals however, whilst GABA accumulates in plants under stress it has not been determined if, how, where and when GABA acts as an endogenous plant signalling molecule. Here, we establish endogenous GABA as a bona fide plant signal, acting via a mechanism not found in animals. Using Arabidopsis thaliana , we show guard cell GABA production is necessary and sufficient to reduce stomatal opening and transpirational water loss, which improves water use efficiency and drought tolerance, via negative regulation of a stomatal guard cell tonoplast-localised anion transporter. We find GABA modulation of stomata occurs in multiple plants, including dicot and monocot crops. This study highlights a role for GABA metabolism in fine tuning physiology and opens alternative avenues for improving plant stress resilience.
Understanding the Molecular Basis of Salt Sequestration in Epidermal Bladder Cells of Chenopodium quinoa
Publisher: Elsevier BV
Date: 10-2018
DOI: 10.1016/J.CUB.2018.08.004
Abstract: Soil salinity is destroying arable land and is considered to be one of the major threats to global food security in the 21st century. Therefore, the ability of naturally salt-tolerant halophyte plants to sequester large quantities of salt in external structures, such as epidermal bladder cells (EBCs), is of great interest. Using Chenopodium quinoa, a pseudo-cereal halophyte of great economic potential, we have shown previously that, upon removal of salt bladders, quinoa becomes salt sensitive. In this work, we analyzed the molecular mechanism underlying the unique salt dumping capabilities of bladder cells in quinoa. The transporters differentially expressed in the EBC transcriptome and functional electrophysiological testing of key EBC transporters in Xenopus oocytes revealed that loading of Na
Sugar beet cold-induced PMT5a and STP13 carriers are poised for taproot proton-driven plasma membrane sucrose and glucose import
Publisher: Cold Spring Harbor Laboratory
Date: 22-09-2021
DOI: 10.1101/2021.09.21.461191
Abstract: As the major sugar-producing crop in the northern hemisphere, sugar beet taproots store sucrose at a concentration of about 20 %. While the vacuolar sucrose loader TST has already been identified in the taproot, sugar transporters mediating sucrose uptake across the plasma membrane of taproot parenchyma cells remained unknown. We electrophysiologically examined taproots for proton-coupled sugar uptake and identified potentially involved transporters by transcriptomic profiling. After cloning, the transporter features were studied in the heterologous Xenopus laevis oocyte expression system using the two-electrode voltage cl technique. Insights into the structure were gained by 3D homology modeling. As with glucose, sucrose stimulation of taproot parenchyma cells caused inward H + -fluxes and plasma membrane depolarization, indicating a sugar roton symport mechanism. As one potential candidate for sugar uploading, the BvPMT5a was characterized as a H + -driven low-affinity glucose transporter, which does not transport sucrose. BvSTP13 operated as a high-affinity H + /sugar symporter, transporting glucose and to some extent sucrose due to a binding cleft plasticity. Both transporter genes were upregulated upon cold exposure, with the transport capacity of BvSTP13 being more cold-resistant than BvPMT5a. Identification of BvPMT5a and BvSTP13 as taproot sugar transporters could improve breeding of cold-tolerant sugar beet to provide a sustainable energy crop.
Stomata in a saline world
Publisher: Elsevier BV
Date: 12-2018
DOI: 10.1016/J.PBI.2018.07.015
Abstract: Salt stress results in a dramatic increase in ABA biosynthesis, H
Salinity Effects on Guard Cell Proteome in Chenopodium quinoa
Publisher: MDPI AG
Date: 04-01-2021
DOI: 10.3390/IJMS22010428
Abstract: Epidermal fragments enriched in guard cells (GCs) were isolated from the halophyte quinoa (Chenopodium quinoa Wild.) species, and the response at the proteome level was studied after salinity treatment of 300 mM NaCl for 3 weeks. In total, 2147 proteins were identified, of which 36% were differentially expressed in response to salinity stress in GCs. Up and downregulated proteins included signaling molecules, enzyme modulators, transcription factors and oxidoreductases. The most abundant proteins induced by salt treatment were desiccation-responsive protein 29B (50-fold), osmotin-like protein OSML13 (13-fold), polycystin-1, lipoxygenase, alpha-toxin, and triacylglycerol lipase (PLAT) domain-containing protein 3-like (eight-fold), and dehydrin early responsive to dehydration (ERD14) (eight-fold). Ten proteins related to the gene ontology term “response to ABA” were upregulated in quinoa GC this included aspartic protease, phospholipase D and plastid-lipid-associated protein. Additionally, seven proteins in the sucrose–starch pathway were upregulated in the GC in response to salinity stress, and accumulation of tryptophan synthase and L-methionine synthase (enzymes involved in the amino acid biosynthesis) was observed. Exogenous application of sucrose and tryptophan, L-methionine resulted in reduction in stomatal aperture and conductance, which could be advantageous for plants under salt stress. Eight aspartic proteinase proteins were highly upregulated in GCs of quinoa, and exogenous application of pepstatin A (an inhibitor of aspartic proteinase) was accompanied by higher oxidative stress and extremely low stomatal aperture and conductance, suggesting a possible role of aspartic proteinase in mitigating oxidative stress induced by saline conditions.
Anion channel SLAH3 is a regulatory target of chitin receptor-associated kinase PBL27 in microbial stomatal closure
Publisher: eLife Sciences Publications, Ltd
Date: 16-09-2019
DOI: 10.7554/ELIFE.44474
Abstract: In plants, antimicrobial immune responses involve the cellular release of anions and are responsible for the closure of stomatal pores. Detection of microbe-associated molecular patterns (MAMPs) by pattern recognition receptors (PRRs) induces currents mediated via slow-type (S-type) anion channels by a yet not understood mechanism. Here, we show that stomatal closure to fungal chitin is conferred by the major PRRs for chitin recognition, LYK5 and CERK1, the receptor-like cytoplasmic kinase PBL27, and the SLAH3 anion channel. PBL27 has the capacity to phosphorylate SLAH3, of which S127 and S189 are required to activate SLAH3. Full activation of the channel entails CERK1, depending on PBL27. Importantly, both S127 and S189 residues of SLAH3 are required for chitin-induced stomatal closure and anti-fungal immunity at the whole leaf level. Our results demonstrate a short signal transduction module from MAMP recognition to anion channel activation, and independent of ABA-induced SLAH3 activation.
Stalk cell polar ion transport provide for bladder‐based salinity tolerance in Chenopodium quinoa
Publisher: Wiley
Date: 06-2022
DOI: 10.1111/NPH.18205
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.
Sugar beet (Beta vulgaris) guard cells responses to salinity stress: A proteomic analysis
Publisher: MDPI AG
Date: 27-03-2020
DOI: 10.3390/IJMS21072331
Abstract: Soil salinity is a major environmental constraint affecting crop growth and threatening global food security. Plants adapt to salinity by optimizing the performance of stomata. Stomata are formed by two guard cells (GCs) that are morphologically and functionally distinct from the other leaf cells. These microscopic sphincters inserted into the wax-covered epidermis of the shoot balance CO2 intake for photosynthetic carbon gain and concomitant water loss. In order to better understand the molecular mechanisms underlying stomatal function under saline conditions, we used proteomics approach to study isolated GCs from the salt-tolerant sugar beet species. Of the 2088 proteins identified in sugar beet GCs, 82 were differentially regulated by salt treatment. According to bioinformatics analysis (GO enrichment analysis and protein classification), these proteins were involved in lipid metabolism, cell wall modification, ATP biosynthesis, and signaling. Among the significant differentially abundant proteins, several proteins classified as “stress proteins” were upregulated, including non-specific lipid transfer protein, chaperone proteins, heat shock proteins, inorganic pyrophosphatase 2, responsible for energized vacuole membrane for ion transportation. Moreover, several antioxidant enzymes (peroxide, superoxidase dismutase) were highly upregulated. Furthermore, cell wall proteins detected in GCs provided some evidence that GC walls were more flexible in response to salt stress. Proteins such as L-ascorbate oxidase that were constitutively high under both control and high salinity conditions may contribute to the ability of sugar beet GCs to adapt to salinity by mitigating salinity-induced oxidative stress.
Elevated CO 2 -Induced Responses in Stomata Require ABA and ABA Signaling
Publisher: Elsevier BV
Date: 10-2015
Salt bladders: Do they matter?
Publisher: Elsevier BV
Date: 11-2014
DOI: 10.1016/J.TPLANTS.2014.09.001
Abstract: Soil salinity is claiming about three hectares of arable land from conventional crop farming every minute. At the same time, the challenge of feeding 9.3 billion people by 2050 is forcing agricultural production into marginal areas, and providing sufficient food for this growing population cannot be achieved without a major breakthrough in crop breeding for salinity tolerance. In this Opinion article, we argue that the current trend of targeting Na(+) exclusion mechanisms in breeding programmes for salinity tolerance in crops needs revising. We propose that progress in this area will be achieved by learning from halophytes, naturally salt-loving plants capable of surviving in harsh saline environments, by targeting the mechanisms conferring Na(+) sequestration in external storage organs.
Calcium sensor kinase activates potassium uptake systems in gland cells of Venus flytraps
Publisher: Proceedings of the National Academy of Sciences
Date: 21-05-2015
Abstract: The Venus flytrap Dionaea muscipula has been in the focus of scientists since Darwin’s time. Carnivorous plants, with their specialized lifestyle, including insect capture, as well as digestion and absorption of prey, developed unique tools to gain scarce nutrients. In this study, we identified the molecular nature of the uptake machinery for prey-derived potassium and the posttranslational regulation. For the first time, to our knowledge, we functionally characterize DmHAK5 here—a KUP/HAK/KT family member as activated by a CBL-CIPK kinase complex. Detailed electrophysiological characterization identified DmHAK5 as a proton-driven, high-affinity potassium transporter with a weak selectivity. Working hand-in-hand with the low-affinity, high-capacity K + -channel DmKT1 activated by the same kinase, the transporters allow the Venus flytrap to take up prey-derived potassium.
Diurnal and Light-Regulated Expression of AtSTP1 in Guard Cells of Arabidopsis
Publisher: Oxford University Press (OUP)
Date: 10-2003
Abstract: Guard cell chloroplasts are unable to perform significant photosynthetic CO2 fixation via Rubisco. Therefore, guard cells depend on carbon supply from adjacent cells even during the light period. Due to their reversible turgor changes, this import cannot be mediated by plasmodesmata. Nevertheless, guard cells of several plants were shown to use extracellular sugars or to accumulate sucrose as an osmoticum that drives water influx to increase stomatal aperture. This paper describes the first localization of a guard cell-specific Arabidopsis sugar transporter involved in carbon acquisition of these symplastically isolated cells. Expression of the AtSTP1 H+-monosacharide symporter gene in guard cells was demonstrated by in situ hybridization and by immunolocalization with an AtSTP1-specific antiserum. Additional RNase protection analyses revealed a strong increase of AtSTP1 expression in the dark and a transient, diurnally regulated increase during the photoperiod around midday. This transient increase in AtSTP1 expression correlates in time with the described guard cell-specific accumulation of sucrose. Our data suggest a function of AtSTP1 in monosaccharide import into guard cells during the night and a possible role in osmoregulation during the day.
The liverwort Marchantia polymorpha operates a depolarization-activated Slowpoke (SLO) K+ channel that recognises pH changes in the environment
Publisher: Cold Spring Harbor Laboratory
Date: 06-2021
DOI: 10.1101/2021.06.01.446568
Abstract: Voltage-dependent ion channels are a prerequisite for cellular excitability and electrical communication – important traits for multicellular organisms to thrive in a changeable terrestrial environment. Based on their presence in extant embryophytes and closely-related green algae, the first plants to survive on land likely possessed genes encoding channels with homology to large-conductance calcium-activated K + channels (BK channels from the Slo family) in addition to primary voltage-gated potassium channels from the plant VG-type family (Shaker or K v channels). While the function and gating of Shaker channels has been characterised in flowering plants, so far knowledge of BK channels has been limited to animal models. In humans, BK-mediated K + efflux has a critical role in sperm motility and membrane polarisation to enable fertilisation. In the liverwort Marchantia polymorpha , the MpBK2a channel gene is most highly expressed in male reproductive tissue, suggesting that these channels may function in sexual reproduction. We characterised MpBK2a channels and found them to be strongly K + -selective, outward-rectifying, 80-pS channels capable of repolarising the membrane after stimulus-dependent depolarisation. In contrast to its animal counterpart, MpBK2a is insensitive to cytoplasmic Ca 2+ variations but effectively gated by pH changes. Given that this plant BK channel is active even in the presence of trace amounts of external K + and at low pH, the liverwort channel could have stabilised the membrane potential under stressful pre-historic conditions including nutrient-depleted and acid environments as early plant pioneers conquered land.
Insect haptoelectrical stimulation of Venus flytrap triggers exocytosis in gland cells
Publisher: Proceedings of the National Academy of Sciences
Date: 17-04-2017
Abstract: The Venus flytrap has been in the focus of scientists since Darwin’s time. Carnivorous plants, with their specialized lifestyle, including insect capture, as well as digestion and absorption of prey, developed unique tools to gain scarce nutrients. In this study, we describe mechanistic insights into the cascade of events following the capture of insect prey. Action potentials evoked by the struggling prey are translated into touch-inducible hormone signals that promote the formation of secretory vesicles. Different varieties of digestive compounds are released sequentially into the flytrap’s “green stomach” and break down the captured animal. Amperometry provides insight into the kinetics and chemistry of the stimulus-coupled glandular secretion process.
Optimization of photosynthesis and stomatal conductance in the date palm Phoenix dactylifera during acclimation to heat and drought
Publisher: Wiley
Date: 29-07-2019
DOI: 10.1111/NPH.15923
Abstract: We studied acclimation of leaf gas exchange to differing seasonal climate and soil water availability in slow-growing date palm (Phoenix dactylifera) seedlings. We used an extended Arrhenius equation to describe instantaneous temperature responses of leaf net photosynthesis (A) and stomatal conductance (G), and derived physiological parameters suitable for characterization of acclimation (T
The epidermal bladder cell‐free mutant of the salt‐tolerant quinoa challenges our understanding of halophyte crop salinity tolerance
Publisher: Wiley
Date: 30-08-2022
DOI: 10.1111/NPH.18420
Abstract: Halophytes tolerate high salinity levels that would kill conventional crops. Understanding salt tolerance mechanisms will provide clues for breeding salt‐tolerant plants. Many halophytes, such as quinoa ( Chenopodium quinoa ), are covered by a layer of epidermal bladder cells (EBCs) that are thought to mediate salt tolerance by serving as salt dumps. We isolated an epidermal bladder cell‐free ( ebcf ) quinoa mutant that completely lacked EBCs and was mutated in REBC and REBC‐like1 . This mutant showed no loss of salt stress tolerance. When wild‐type quinoa plants were exposed to saline soil, EBCs accumulated potassium (K + ) as the major cation, in quantities far exceeding those of sodium (Na + ). Emerging leaves densely packed with EBCs had the lowest Na + content, whereas old leaves with deflated EBCs served as Na + sinks. When the leaves expanded, K + was recycled from EBCs, resulting in turgor loss that led to a progressive deflation of EBCs. Our findings suggest that EBCs in young leaves serve as a K + ‐powered hydrodynamic system that functions as a water sink for solute storage. Sodium ions accumulate within old leaves that subsequently wilt and are shed. This mechanism improves the survival of quinoa under high salinity conditions.
The Venus Flytrap Dionaea muscipula Counts Prey-Induced Action Potentials to Induce Sodium Uptake
Publisher: Elsevier BV
Date: 02-2016
Related Organisations
Georg-August-Universität Göttingen Biologische Fakultät
Location: Germany
Related Funding Activities
Discovery Projects - Grant ID: DP140100666
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End Date: 12-2017
Amount: $348,000.00
Funder: Australian Research Council
View Funded ActivityDiscovery Projects - Grant ID: DP150101663
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End Date: 12-2020
Amount: $402,800.00
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View Funded ActivityDiscovery Projects - Grant ID: DP170100430
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End Date: 12-2020
Amount: $446,500.00
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View Funded ActivityDiscovery Projects - Grant ID: DP210102828
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End Date: 11-2024
Amount: $509,000.00
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View Funded ActivityDiscovery Projects - Grant ID: DP170104384
Start Date: 2017
End Date: 12-2019
Amount: $375,000.00
Funder: Australian Research Council
View Funded Activity