Regulation Of Stomatal Movement Research Articles

Zinc Finger-Homeodomain Transcriptional Factors (ZHDs) in Cucumber (Cucumis sativus L.): Identification, Evolution, Expression Profiles, and Function under Abiotic Stresses.

Cucumber (Cucumis sativus L.) is a globally prevalent and extensively cultivated vegetable whose yield is significantly influenced by various abiotic stresses, including drought, heat, and salinity. Transcription factors, such as zinc finger-homeodomain proteins (ZHDs), a plant-specific subgroup of Homeobox, play a crucial regulatory role in stress resistance. In this study, we identified 13 CsZHDs distributed across all six cucumber chromosomes except chromosome 7. Phylogenetic analysis classified these genes into five clades (ZHDI-IV and MIF) with different gene structures but similar conserved motifs. Collinearity analysis revealed that members of clades ZHD III, IV, and MIF experienced amplification through segmental duplication events. Additionally, a closer evolutionary relationship was observed between the ZHDs in Cucumis sativus (C. sativus) and Arabidopsis thaliana (A. thaliana) compared to Oryza sativa (O. sativa). Quantitative real-time PCR (qRT-PCR) analysis demonstrated the general expression of CsZHD genes across all tissues, with notable expression in leaf and flower buds. Moreover, most of the CsZHDs, particularly CsZHD9-11, exhibited varying responses to drought, heat, and salt stresses. Virus-induced gene silencing (VIGS) experiments highlighted the potential functions of CsZHD9 and CsZHD10, suggesting their positive regulation of stomatal movement and responsiveness to drought stress. In summary, these findings provide a valuable resource for future analysis of potential mechanisms underlying CsZHD genes in response to stresses.

A novel semi-dominant mutation in brassinosteroid signaling kinase1 increases stomatal density.

Stomata play a pivotal role in balancing CO2 uptake for photosynthesis and water loss via transpiration. Thus, appropriate regulation of stomatal movement and its formation are crucial for plant growth and survival. Red and blue light induce phosphorylation of the C-terminal residue of the plasma membrane (PM) H+-ATPase, threonine, in guard cells, generating the driving force for stomatal opening. While significant progress has been made in understanding the regulatory mechanism of PM H+-ATPase in guard cells, the regulatory components for the phosphorylation of PM H+-ATPase have not been fully elucidated. Recently, we established a new immunohistochemical technique for detecting guard-cell PM H+-ATPase phosphorylation using leaves, which was expected to facilitate investigations with a single leaf. In this study, we applied the technique to genetic screening experiment to explore novel regulators for the phosphorylation of PM H+-ATPase in guard cells, as well as stomatal development. We successfully performed phenotyping using a single leaf. During the experiment, we identified a mutant exhibiting high stomatal density, jozetsu (jzt), named after a Japanese word meaning 'talkative'. We found that a novel semi-dominant mutation in BRASSINOSTEROID SIGNALING KINASE1 (BSK1) is responsible for the phenotype in jzt mutant. The present results demonstrate that the new immunohistochemical technique has a wide range of applications, and the novel mutation would provide genetic tool to expand our understanding of plant development mediated by brassinosteroid signaling.

Abscisic acid root-to-shoot translocation by transporter AtABCG25 mediates stomatal movements in Arabidopsis.

The phytohormone abscisic acid (ABA) plays a central role in regulating stomatal movements under drought conditions. The root-derived peptide CLAVATA3/EMBRYO SURROUNDING REGION-RELATED 25 (CLE25) moves from the root to shoot for activating ABA biosynthesis under drought conditions. However, the root-to-shoot translocation of root-derived ABA and its regulation of stomatal movements in the shoot remain to be clarified. Here, we reveal that the ABA transporter ATP-binding cassette subfamily G member 25 (AtABCG25) mediates root-to-shoot translocation of ABA and ABA-glucosyl ester (ABA-GE) in Arabidopsis (Arabidopsis thaliana). Isotope-labeled ABA tracer experiments and hormone quantification in xylem sap showed that the root-to-shoot translocation of ABA and ABA-GE was substantially impaired in the atabcg25 mutant under nondrought and drought conditions. However, the contents of ABA and ABA-GE in the leaves were lower in the atabcg25 mutant than in the wild type (WT) under nondrought but similar under drought conditions. Consistently, the stomatal closure was suppressed in the atabcg25 mutant under nondrought but not under drought conditions. The transporter activity assays showed that AtABCG25 directly exported ABA and ABA-GE in planta and in yeast (Saccharomyces cerevisiae) cells. Thus, we proposed a working model in which root-derived ABA transported by AtABCG25 via xylem mediates stomatal movements in the shoot under nondrought conditions but might exhibit little effect on stomatal movements under drought conditions. These findings extend the functions of AtABCG25 and provide insights into the long-distance translocation of ABA and its role in stomatal movements.

Fructose Regulation of Stomatal Movement and its Effects on the Photosynthetic System in Vicia faba L.

Background: Vicia faba L. is a significant grain legume that is rich in protein and nutrients. It is widely cultivated for human consumption and animal feed in temperate regions. As a signaling molecule, fructose is involved in many metabolic and developmental processes. The objective of this study was to demonstrate whether fructose may increase reactive oxygen species (ROS) production in guard cells inducing stomatal closure and examine whether the exogenous application of fructose may regulate photosynthesis and chlorophyll fluorescence characteristics. Methods: After approximately 4 weeks of sowing the treated broad bean seeds, the fully inflated leaves were used for experimental data collection including stomatal movement, gas exchange, chlorophyll fluorescence and ROS production in guard cells. Result: Fructose reduced stomatal conductance (Gs), transpiration rate (Tr) and stomatal aperture of intact leaves, indicating that fructose can trigger stomatal closure in a dose- and time-dependent manner in the epidermal peels of the broad bean plant (Vicia faba L.). Meanwhile, fructose increased the photochemical efficiency, photosynthetic rate (Pn) and water use efficiency (WUE). Fructose-induced stomatal closure was associated with nitric oxide (NO), calcium ion (Ca2+), aquaporin and ROS.

RtNAC055 promotes drought tolerance via a stomatal closure pathway linked to methyl jasmonate/hydrogen peroxide signaling in Reaumuria trigyna.

The stomata regulate CO2 uptake and efficient water usage, thereby promoting drought stress tolerance. NAC proteins (NAM, ATAF1/2, and CUC2) participate in plant reactions following drought stress, but the molecular mechanisms underlying NAC-mediated regulation of stomatal movement are unclear. In this study, a novel NAC gene from Reaumuria trigyna, RtNAC055, was found to enhance drought tolerance via a stomatal closure pathway. It was regulated by RtMYC2 and integrated with jasmonic acid signaling and was predominantly expressed in stomata and root. The suppression of RtNAC055 could improve jasmonic acid and H2O2 production and increase the drought tolerance of transgenic R. trigyna callus. Ectopic expression of RtNAC055 in the Arabidopsis atnac055 mutant rescued its drought-sensitive phenotype by decreasing stomatal aperture. Under drought stress, overexpression of RtNAC055 in poplar promoted ROS (H2O2) accumulation in stomata, which accelerated stomatal closure and maintained a high photosynthetic rate. Drought upregulated the expression of PtRbohD/F, PtP5CS2, and PtDREB1.1, as well as antioxidant enzyme activities in heterologous expression poplars. RtNAC055 promoted H2O2 production in guard cells by directly binding to the promoter of RtRbohE, thus regulating stomatal closure. The stress-related genes RtDREB1.1/P5CS1 were directly regulated by RtNAC055. These results indicate that RtNAC055 regulates stomatal closure by maintaining the balance between the antioxidant system and H2O2 level, reducing the transpiration rate and water loss, and improving photosynthetic efficiency and drought resistance.

Maize GOLDEN2-LIKE proteins enhance drought tolerance in rice by promoting stomatal closure.

Drought has become one of the most severe abiotic stresses experienced in agricultural production across the world. Plants respond to water deficit via stomatal movements in the leaves, which are mainly regulated by abscisic acid (ABA). A previous study from our lab showed that constitutive expression of maize (Zea mays L.) GOLDEN2-LIKE (GLK) transcription factors in rice (Oryza sativa L.) can improve stomatal conductance and plant photosynthetic capacity under field conditions. In the present study, we uncovered a function of ZmGLK regulation of stomatal movement in rice during drought stress. We found that elevated drought tolerance in rice plants overexpressing ZmGLK1 or GOLDEN2 (ZmG2) was conferred by rapid ABA-mediated stomatal closure. Comparative analysis of RNA-sequencing (RNA-seq) data from the rice leaves and DNA affinity purification sequencing (DAP-seq) results obtained in vitro revealed that ZmGLKs played roles in regulating ABA-related and stress-responsive pathways. Four upregulated genes closely functioning in abiotic stress tolerance with strong binding peaks in the DAP-seq data were identified as putative target genes of ZmGLK1 and ZmG2 in rice. These results demonstrated that maize GLKs play an important role in regulating stomatal movements to coordinate photosynthesis and stress tolerance. This trait is a valuable target for breeding drought-tolerant crop plants without compromising photosynthetic capacity.

Low R:FR light ratio enhances calcium nitrate resistance and stomatal movement in tomato seedlings by regulating H2O2 accumulation

Secondary salinization is a major environmental factor that causes a stress response and growth inhibition in plants in protected agriculture. The positive effect of a low red to far-red light ratio (R:FR) in salt tolerance through antioxidant defense has been reported, while the underlying model remains obscure. In this study, we used physiological and genetic approaches to investigate the relationship between H2O2 signaling and low R:FR-induced salt tolerance and antioxidant capacity in tomato seedlings. This study found that low R:FR treatment with calcium nitrate stress (SL treatment) enhanced the growth of plants and increased the net photosynthetic rate 5 days after stress compared with a higher R:FR ratio and calcium nitrate stress (S treatment). With transcriptomic analysis of tomato leaves at 5 d, compared with CK, most of glutaredoxin genes and antioxidant enzymes were upregulated by S treatment, which were upregulated further by SL treatment. Compared to the S treatment, within 5 days, the H2O2 level was increased faster before 24 h and it was slowed down after 24 h by SL treatment, with less H2O2 accumulation at 5 d than that of S treatment. The enhancement of gene expression of RBOH genes were also shown at 24 h under SL. It was found that stomatal conductance followed the dynamic change of H2O2, with a rapid closure of stomata and decrease at 3 h and an increase after 9 h in SL treatment compared to S treatment, respectively. There was same trend of stomata opening degrees of tomato leaves observed by optical microscope. However, the inhibitor of H2O2 production (DPI pretreatment) weakened the positive effect of low R:FR on the regulation of stomatal movement. In addition, SL treatment increased the antioxidant enzyme activities and proline content and decreased the MDA content as compared to the S treatment, while the enhancement of ROS homeostasis was reduced by the DPI pretreatment. In conclusion, low R:FR improved redox homeostasis and stomatal status under calcium nitrate stress through H2O2 signaling, improving the adaptation of tomato seedlings to soil salinization stress.

Recent Updates on ALMT Transporters' Physiology, Regulation, and Molecular Evolution in Plants.

Aluminium toxicity and phosphorus deficiency in soils are the main interconnected problems of modern agriculture. The aluminium-activated malate transporters (ALMTs) comprise a membrane protein family that demonstrates various physiological functions in plants, such as tolerance to environmental Al3+ and the regulation of stomatal movement. Over the past few decades, the regulation of ALMT family proteins has been intensively studied. In this review, we summarise the current knowledge about this transporter family and assess their involvement in diverse physiological processes and comprehensive regulatory mechanisms. Furthermore, we have conducted a thorough bioinformatic analysis to decipher the functional importance of conserved residues, structural components, and domains. Our phylogenetic analysis has also provided new insights into the molecular evolution of ALMT family proteins, expanding their scope beyond the plant kingdom. Lastly, we have formulated several outstanding questions and research directions to further enhance our understanding of the fundamental role of ALMT proteins and to assess their physiological functions.

PECT1, a rate-limiting enzyme in phosphatidylethanolamine biosynthesis, is involved in the regulation of stomatal movement in Arabidopsis.

An Arabidopsis mutant displaying impaired stomatal responses to CO2 , cdi4, was isolated by a leaf thermal imaging screening. The mutated gene PECT1 encodes CTP:phosphorylethanolamine cytidylyltransferase. The cdi4 exhibited a decrease in levels and a defect in light-induced stomatal opening as well as low-CO2 -induced stomatal opening. We created RNAi lines in which PECT1 was specifically repressed in guard cells. These lines are impaired in their stomatal responses to low-CO2 concentrations or light. Fungal toxin fusicoccin (FC) promotes stomatal opening by activating plasma membrane H+ -ATPases in guard cells via phosphorylation. Arabidopsis H+ -ATPase1 (AHA1) has been reported to be highly expressed in guard cells, and its activation by FC induces stomatal opening. The cdi4 and PECT1 RNAi lines displayed a reduced stomatal opening response to FC. However, similar to in the wild-type, cdi4 maintained normal levels of phosphorylation and activation of the stomatal H+ -ATPases after FC treatment. Furthermore, the cdi4 displayed normal localization of GFP-AHA1 fusion protein and normal levels of AHA1 transcripts. Based on these results, we discuss how PECT1 could regulate CO2 - and light-induced stomatal movements in guard cells in a manner that is independent and downstream of the activation of H+ -ATPases.

ALA reverses ABA-induced stomatal closure by modulating PP2AC and SnRK2.6 activity in apple leaves.

5-Aminolevulinic acid (ALA), known as a new natural plant growth regulator, can reverse abscisic acid (ABA)-induced stomatal closure. The protein phosphatase 2A (PP2A) played an important role in regulation of stomatal movement by ALA and ABA; however, the underlying molecular mechanisms remain unclear. Here, we report that ALA promotes MdPP2A activity and gene expression in the leaf epidermis of apple (Malus × domestica Borkh.), and expression of the catalytic subunit MdPP2AC was most significantly correlated with stomatal aperture. Western blotting showed that ALA enhanced MdPP2AC protein abundance and phosphorylation. Y2H (yeast two hybrid), FLC (firefly luciferase complementation imaging) and BiFC (Bimolecular fluorescence complementation) assays showed that MdPP2AC interacted with several other MdPP2A subunits as well as MdSnRK2.6 (Sucrose non-fermenting 1-related protein kinase 2.6), and the latter interaction was further verified by pull-down and MST (microscale thermophoresis) assays. ALA downregulated ABA-induced MdSnRK2.6 gene expression, kinase activity, and protein phosphorylation. In transiently transgenic apple leaves, OE-MdPP2AC promoted stomatal aperture by reducing Ca2+ and H2O2 levels but increasing flavonol levels in guard cells. Conversely, OE-MdSnRK2.6 induced stomatal closure by increasing Ca2+ and H2O2 but reducing flavonols. Partial silencing of these genes had opposite effects on Ca2+, H2O2, flavonols, and stomatal movement. Application of exogenous ALA stimulated PP2A activity, which promoted SnRK2.6 dephosphorylation and lower kinase activity in wild-type and transgenic apple leaves. We therefore propose that PP2AC, which dephosphorylates SnRK2.6 and represses its enzyme activity, mediates ALA signaling to inhibit ABA-induced stomatal closure in apple leaves.

Hydrogen sulfide mediated the melatonin induced stoma closure by regulating the K+ channel in Arabidopsis thaliana

The roles of the gasotransmitter hydrogen sulfide (H2S) and the phytohormone melatonin (MEL) in enhancing plant drought resistance are increasingly understood, but the specific regulatory mechanisms in response to drought remain unclear. This study investigated their relationship in the regulation of stomatal movement in response to drought stress. Under normal and drought stress conditions, exogenous MEL increased the H2S content, production rate and the transcription level of H2S production-related encoding genes LCD and DES1. The ability of MEL to increase drought stress tolerance was inhibited significantly in lcd, des1 and lcd/des1 mutants, which implied that MEL was partially dependent on H2S in this process. Exogenous MEL and H2S increased the transcriptional level of drought related transcription factors CBF2, CBF3, RD29A, DREB2A and DREB2B in response to drought stress and H2S and MEL affected the transcription level of K+ channel-related genes KCO1, GORK, AKT1, AKT2, KAT1, and KC1 to regulate stomatal movement. At the post-translational level, H2S increased the persulfidation levels of KCO1 and AKT1 and reduced their degradation rate. It was also found that endogenous H2S and MEL content had no effect on the mutants of kco1, kat1, akt1 and gork. It was concluded that H2S mediated the MEL induced stoma closure by regulating the K+ channel to enhance plant drought resistance in Arabidopsis.

Improvement of plant tolerance to drought stress by cotton tubby-like protein 30 through stomatal movement regulation

IntroductionCotton is a vital industrial crop that is gradually shifting to planting in arid areas. However, tubby-like proteins (TULPs) involved in plant response to various stresses are rarely reported in cotton. The present study exhibited that GhTULP30 transcription in cotton was induced by drought stress. ObjectiveThe present study demonstrated the improvement of plant tolerance to drought stress by GhTULP30 through regulation of stomatal movement. MethodsGhTULP30 response to drought and salt stress was preliminarily confirmed by qRT-PCR and yeast stress experiments. Ectopic expression in Arabidopsis and endogenous gene silencing in cotton were used to determine stomatal movement. Yeast two-hybrid and spilt-luciferase were used to screen the interacting proteins. ResultsEctopic expression of GhTULP30 in yeast markedly improved yeast cell tolerance to salt and drought. Overexpression of GhTULP30 made Arabidopsis seeds more resistant to drought and salt stress during seed germination and increased the stomata closing speed of the plant under drought stress conditions. Silencing of GhTULP30 in cotton by virus-induced gene silencing (VIGS) technology slowed down the closure speed of stomata under drought stress and decreased the length and width of the stomata. The trypan blue and diaminobenzidine staining exhibited the severity of leaf cell necrosis of GhTULP30-silenced plants. Additionally, the contents of proline, malondialdehyde, and catalase of GhTULP30-silenced plants exhibited significant variations, with obvious leaf wilting. Protein interaction experiments exhibited the interaction of GhTULP30 with GhSKP1B and GhXERICO. ConclusionGhTULP30 participates in plant response to drought stress. The present study provides a reference and direction for further exploration of TULP functions in cotton plants.

Sulfur Compounds in Regulation of Stomatal Movement.

Sulfur, widely present in the soil and atmosphere, is one of the essential elements for plants. Sulfate is a dominant form of sulfur in soils taken up by plant roots. In addition to the assimilation into sulfur compounds essential for plant growth and development, it has been reported recently that sulfate as well as other sulfur containing compounds can also induce stomatal movement. Here, we first summarized the uptake and transport of sulfate and atmospheric sulfur, including H2O and SO2, and then, focused on the effects of inorganic and organic sulfur on stomatal movement. We concluded all the transporters for different sulfur compounds, and compared the expression level of those transporters in guard cells and mesophyll cells. The relationship between abscisic acid and sulfur compounds in regulation of stomatal movement were also discussed.

Salinity mediated cross-tolerance of arsenic toxicity in the halophyte Salvadora persica L. through metabolomic dynamics and regulation of stomatal movement and photosynthesis

Arsenic (As) is a highly toxic metalloid adversely affecting the environment, human health, and crop productivity. The present study assessed the synergistic effects of salinity and As on photosynthetic attributes, stomatal regulations, and metabolomics responses of the xero-halophyte Salvadora persica to decipher the As-salinity cross-tolerance mechanisms and to identify the potential metabolites/metabolic pathways involved in cross-tolerance of As with salinity. Salinity and As stress-induced significant stomatal closure in S. persica suggests an adaptive response to decrease water loss through transpiration. NaCl supplementation improved the net photosynthetic rate (by +39%), stomatal conductance (by +190%), water use efficiency (by +55%), photochemical quenching (by +37%), and electron transfer rate (54%) under As stress as compared to solitary As treatment. Our results imply that both stomatal and non-stomatal factors account for a reduction in photosynthesis under high salinity and As stress conditions. A total of 64 metabolites were identified in S. persica under salinity and/or As stress, and up-regulation of various metabolites support early As-salinity stress tolerance in S. persica by improving antioxidative defense and ROS detoxification. The primary metabolites such as polyphenols (caffeic acid, catechin, gallic acid, coumaric acid, rosmarinic acid, and cinnamic acid), amino acids (glutamic acid, cysteine, glycine, lysine, phenylalanine, and tyrosine), citrate cycle intermediates (malic acid, oxalic acid, and α-ketoglutaric acid), and most of the phytohormones accumulated at higher levels under combined treatment of As + NaCl compared to solitary treatment of As. Moreover, exogenous salinity increased glutamate, glycine, and cysteine, which may induce higher synthesis of GSH-PCs in S. persica. The metabolic pathways that were significantly affected in response to salinity and/or As include inositol phosphate metabolism, citrate cycle, glyoxylate and dicarboxylate metabolism, amino acid metabolism, and glutathione metabolism. Our findings indicate that inflections of various metabolites and metabolic pathways facilitate S. persica to withstand and grow optimally even under high salinity and As conditions. Moreover, the addition of salt enhanced the arsenic tolerance proficiency of this halophyte.

Hierarchical transcription factor and regulatory network for drought response in Betula platyphylla.

Although many genes and biological processes involved in abiotic stress response have been identified, how they are regulated remains largely unclear. Here, to study the regulatory mechanism of birch (Betula platyphylla) responding to drought induced by polyethylene glycol (PEG) 6000 (20%, w/v), a partial correlation coefficient-based algorithm for constructing gene regulatory network (GRN) was proposed, and a three-layer hierarchical GRN was constructed, including 68 transcription factors (TFs), and 252 structural genes. Totally, 1448 predicted regulatory relationships are included, and most of them are novel. The reliability of GRN was verified by ChIP-PCR and qRT-PCR based on transient transformation. About 55% of genes in the bottom layer of GRN could confer drought tolerance. We selected the two TFs, BpMADS11 and BpNAC090, from the up layer and characterized their function in drought tolerance. Overexpression of BpMADS11 and BpNAC090 both reduces electrolyte leakage, ROS and MDA contents, displaying increased drought tolerance than wild-type birch. According to this GRN, the important biological processes involved in drought were identified, including "signaling hormone pathways", "water transport", "regulation of stomatal movement" and "response to oxidative stress". This work indicated that BpERF017, BpAGL61 and BpNAC090 are the key upstream regulators in birch drought tolerance. Our data clearly revealed the upstream regulators and TF-DNA interaction regulate different biological processes to adapt drought stress.

Protein Phosphorylation Changes During Systemic Acquired Resistance in Arabidopsis thaliana.

Systemic acquired resistance (SAR) in plants is a defense response that provides resistance against a wide range of pathogens at the whole-plant level following primary infection. Although the molecular mechanisms of SAR have been extensively studied in recent years, the role of phosphorylation that occurs in systemic leaves of SAR-induced plants is poorly understood. We used a data-independent acquisition (DIA) phosphoproteomics platform based on high-resolution mass spectrometry in an Arabidopsis thaliana model to identify phosphoproteins related to SAR establishment. A total of 8011 phosphorylation sites from 3234 proteins were identified in systemic leaves of Pseudomonas syringae pv. maculicola ES4326 (Psm ES4326) and mock locally inoculated plants. A total of 859 significantly changed phosphoproteins from 1119 significantly changed phosphopeptides were detected in systemic leaves of Psm ES4326 locally inoculated plants, including numerous transcription factors and kinases. A variety of defense response-related proteins were found to be differentially phosphorylated in systemic leaves of Psm ES4326 locally inoculated leaves, suggesting that these proteins may be functionally involved in SAR through phosphorylation or dephosphorylation. Significantly changed phosphoproteins were enriched mainly in categories related to response to abscisic acid, regulation of stomatal movement, plant–pathogen interaction, MAPK signaling pathway, purine metabolism, photosynthesis-antenna proteins, and flavonoid biosynthesis. A total of 28 proteins were regulated at both protein and phosphorylation levels during SAR. RT-qPCR analysis revealed that changes in phosphorylation levels of proteins during SAR did not result from changes in transcript abundance. This study provides comprehensive details of key phosphoproteins associated with SAR, which will facilitate further research on the molecular mechanisms of SAR.

Crosstalk between Light- and Temperature-Mediated Processes under Cold and Heat Stress Conditions in Plants.

Extreme temperatures are among the most important stressors limiting plant growth and development. Results indicate that light substantially influences the acclimation processes to both low and high temperatures, and it may affect the level of stress injury. The interaction between light and temperature in the regulation of stress acclimation mechanisms is complex, and both light intensity and spectral composition play an important role. Higher light intensities may lead to overexcitation of the photosynthetic electron transport chain; while different wavelengths may act through different photoreceptors. These may induce various stress signalling processes, leading to regulation of stomatal movement, antioxidant and osmoregulation capacities, hormonal actions, and other stress-related pathways. In recent years, we have significantly expanded our knowledge in both light and temperature sensing and signalling. The present review provides a synthesis of results for understanding how light influences the acclimation of plants to extreme low or high temperatures, including the sensing mechanisms and molecular crosstalk processes.

Boolink: a graphical interface for open access Boolean network simulations and use in guard cell CO2 signaling.

Signaling networks are at the heart of almost all biological processes. Most of these networks contain large number of components, and often either the connections between these components are not known or the rate equations that govern the dynamics of soluble signaling components are not quantified. This uncertainty in network topology and parameters can make it challenging to formulate detailed mathematical models. Boolean networks, in which all components are either on or off, have emerged as viable alternatives to detailed mathematical models that contain rate constants and other parameters. Therefore, open-source platforms of Boolean models for community use are desirable. Here, we present Boolink, a freely available graphical user interface that allows users to easily construct and analyze existing Boolean networks. Boolink can be applied to any Boolean network. We demonstrate its application using a previously published network for abscisic acid (ABA)-driven stomatal closure in Arabidopsis spp. (Arabidopsis thaliana). We also show how Boolink can be used to generate testable predictions by extending the network to include CO2 regulation of stomatal movements. Predictions of the model were experimentally tested, and the model was iteratively modified based on experiments showing that ABA effectively closes Arabidopsis stomata at near-zero CO2 concentrations (1.5-ppm CO2). Thus, Boolink enables public generation and the use of existing Boolean models, including the prior developed ABA signaling model with added CO2 signaling components.

A Prototypical Conjugated Polymer Regulating Signaling in Plants

AbstractThe use of nanomaterials has been very recently introduced in plant biotechnologies, for both the monitoring and the enhancement of plants functions. Several functional interfaces between living plants and nanotechnology have been successfully reported for diverse applications, from sensing to photosynthesis and energy production and from modulation of physiological activity to controlled delivery of chemicals. In this work, a photoactive, biohybrid interface based on a prototypical semiconducting polymer, sensitive to green light, and Arabidopsis thaliana plants is reported. Optical excitation of polymer beads is shown to deterministically regulate the Arabidopsis stomatal aperture, the leaf pores which regulate the plant carbon dioxide uptake, oxygen release, and transpiration processes. Moreover, it is observed that excitation of bio‐polymer hybrid interfaces optically modulates the cytosolic calcium ions concentration, which is involved, as a second messenger, in the regulation of stomatal movements. The results support the possibility to employ light‐responsive organic materials to regulate on demand the physiological activity of plant systems, in a drug‐free, touchless, and easily controllable way. When transferred to the field, this strategy may represent an innovative approach to optimize the exchange of gases and water loss of plants, and to improve the plant resilience toward environmental constraints.

Stomatal regulation: Role of H2S-induced persulfidation in ABA signaling

Stomatal regulation: Role of H2S-induced persulfidation in ABA signaling