Biology subjects

Bartosova, Z.

Publications and source records attributed to Bartosova, Z..

7 recordsLinked to original sources

bioRxiv2026

The interactome of the receptor kinase THESEUS1 reveals how cell wall integrity is linked to hormone signalling in Arabidopsis

The receptor kinase THESEUS1 (THE1) activates responses to impairment of cell wall integrity (CWI). However, the interaction partners enabling THE1 to mediate the responses remain underexplored, impeding a mechanistic understanding of THE1. We produced a set of THE1 GFP fusion constructs in which THE1 is either wild type, mutated in its kinase domain, has a loss of function mutation in its ectodomain, or lacks the kinase or extracellular domain. We used these constructs to perform localization studies and immunoprecipitation liquid chromatography tandem mass spectrometry under control and stress conditions (isoxaben induced cell wall damage and sorbitol induced hyperosmotic stress) to identify the THE1 interactome. The interactome of THE1 changed in a context dependent manner, linking THE1 to known signaling components in CWI maintenance and phytohormone response (such as proton pumps, calcium pumps, other receptor kinases or cellulose synthesis regulators). Moreover, we identified novel interactors, associating THE1 with hitherto unexplored signaling pathways in response to CWI impairment. Our results also suggest that the THE1G37D protein (corresponding to the the1 1 allele) is retained in the endoplasmic reticulum, explaining its loss of function phenotype. The THE1 interactome and localization data provide the foundation to build a mechanistic understanding of THE1 mediated CWI maintenance.

plant biology↗

bioRxiv2025

Coping with stress: Transcriptional regulators linking cell wall integrity maintenance with primary-wall metabolism in Arabidopsis thaliana

Cell wall damage (CWD) and hyperosmotic stress elicit both distinct and overlapping transcriptional programs in plants. Responses to these stresses involve cell wall integrity (CWI) maintenance, which is mediated by receptor-like kinases such as THESEUS1 (THE1), yet the downstream regulators linking early signalling to primary cell-wall metabolism and stress-induced phytohormone biosynthesis remain poorly defined. We induced CWD and hyperosmotic stress in wild type and the1 mutant alleles with isoxaben (ISX) and sorbitol, and analysed the gene expression of treated seedlings by RNA-seq. From these data, we focused on 15 transcriptional regulators whose expression was responsive to treatments and showed dependency on THE1 activity. Following up, we performed various functional analyses in mutant lines of these candidates and identified transcription factors that influence primary cell-wall metabolism, growth, transcriptional control of cellulose production, resistance to CWD and hyperosmotic stress, as well as phytohormone and lignin biosynthesis. Our results identify JMJ17, bHLH, and CBP60A as essential transcriptional regulators involved in responses to CWD and hyperosmotic stress, and they provide a starting point for dissecting the transcriptional network that regulates CWI maintenance and primary cell wall metabolism. This study sheds light on a previously unknown signalling network that regulates primary cell wall synthesis in control and stress conditions, providing a basis for more resilient crop plant breeding in the future. Significance StatementPlants provide food and materials used by society, and their productivity depends on maintaining cell wall integrity (CWI) during growth, development, and environmental stress. The CWI maintenance mechanism, involving receptor-like kinases such as THESEUS1 (THE1), has been extensively investigated, yet the transcriptional regulators involved in primary wall metabolism and stress-induced phytohormone production remain unknown. Here, we integrate transcriptomics with functional genetic and physiological assays to identify transcription factors acting in a THE1-dependent/independent manner. These regulators link CWI, hyperosmotic stress, and cell wall damage to primary wall metabolism, lignification, phytohormone production, and root growth. Our findings reveal elements of the transcriptional network that coordinate CWI and primary cell wall formation with adaptive responses, generating insights to enhance crop stress resilience.

plant biology↗

bioRxiv2024

Migration of endocrine and metabolism disrupting chemicals from plastic food packaging

Plastics constitute a vast array of substances, with over 16 000 known plastic chemicals, including intentionally and non-intentionally added substances. Toxicity and thousands of chemicals are extractable from plastics; however, the extent to which toxicity and chemicals migrate from everyday plastic products remains poorly understood. This study aims to characterize the endocrine and metabolism disrupting activity, as well as chemical composition of migrates from plastic food contact articles (FCAs) from four countries as significant sources of human exposure. Additionally, strategies for prioritization of chemicals were explored. Fourteen plastic FCAs covering seven polymer types with high global market shares were migrated into water and a water-ethanol mixture as food simulants according to European regulations. The migrates were analyzed using reporter gene assays for nuclear receptors relevant to human health and non-target chemical analysis to characterize the chemical composition of the migrates. All FCA migrates interfered with at least two nuclear receptors, predominantly targeting pregnane X receptor. Moreover, peroxisome proliferator receptor gamma was broadly activated by the migrates, though mostly with lower potencies, while estrogenic and antiandrogenic activities were more selectively induced by specific FCAs. Fewer chemicals and less toxicity migrated into water compared to the water-ethanol mixture. The latter exhibited similar toxicity and number of chemicals as methanol extracts of the same FCAs. Novel strategies were employed to address the chemical complexity of FCAs and narrow down the list of potential active chemicals. By comparing the composition of multiple leachates of one sample and using stepwise partial least squares regressions, we successfully reduced the chemical complexity, pinpointed potential endocrine disruptors such as triphenyl phosphate and prioritized chemicals for further identification efforts. This study demonstrates the migration of endocrine and metabolism disrupting chemicals from plastic FCAs into food simulants, rendering a migration of these compounds into food and beverages probable. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=113 SRC="FIGDIR/small/588263v4_ufig1.gif" ALT="Figure 1"> View larger version (42K): org.highwire.dtl.DTLVardef@32490dorg.highwire.dtl.DTLVardef@15a1047org.highwire.dtl.DTLVardef@1e2b565org.highwire.dtl.DTLVardef@f323e2_HPS_FORMAT_FIGEXP M_FIG C_FIG

pharmacology and toxicology↗

bioRxiv2023

Beyond the nucleus: Plastic chemicals activate G protein-coupled receptors

O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=84 SRC="FIGDIR/small/560665v1_ufig1.gif" ALT="Figure 1"> View larger version (23K): org.highwire.dtl.DTLVardef@e3b5edorg.highwire.dtl.DTLVardef@1bcf3aeorg.highwire.dtl.DTLVardef@224012org.highwire.dtl.DTLVardef@9c61ea_HPS_FORMAT_FIGEXP M_FIG C_FIG G protein-coupled receptors (GPCRs) are central mediators of cell signaling and physiological function. Despite their biological significance, GPCRs have not been widely studied in the field of toxicology. Herein, we investigated these receptors are novel targets of plastic chemicals using a high-throughput drug screening assay with 126 human non-olfactory GPCRs. In a first-pass screen, we tested the activity of triphenol phosphate, bisphenol A, and diethyl phthalate as well as three real-world mixtures of chemicals extracted from plastic food packaging covering all major polymer types. We found 11 GPCR-chemical interactions, of which the chemical mixtures exhibited the most robust activity at Adenosine receptor 1 (ADORA1) and Melatonin receptor 1 (MTNR1A) in a confirmatory secondary screen. We further confirmed that polyvinyl chloride and polyurethane products contain ADORA1 or MTNRA1 agonists using pharmacological knockdown experiments. Finally, an analysis of the associated gene ontology terms suggests that ADORA1 and MTNR1A activation may be linked to downstream effects on circadian and metabolic processes. Our findings exemplify the diversity of endpoints plastic chemicals can target and demonstrate the relevance of non-genomic pathways which have thus far remained unexplored.

pharmacology and toxicology↗

bioRxiv2023

Plastic food packaging from five countries contains endocrine and metabolism disrupting chemicals

Plastics are complex chemical mixtures of polymers and various intentionally and non-intentionally added substances. Despite the well-established links between certain plastic chemicals (bisphenols, phthalates) and adverse health effects, the composition and toxicity of real-world mixtures of plastic chemicals is not well understood. To assess both, we analyzed the chemicals from 36 plastic food contact articles from five countries using nontarget high-resolution mass spectrometry and reporter gene assays for four nuclear receptors that represent key components of the endocrine and metabolic system. We found that chemicals activating the pregnane X receptor (PXR), peroxisome proliferator receptor gamma (PPAR{gamma}), estrogen receptor alpha (ER) and inhibiting the androgen receptor (AR) are prevalent in plastic packaging. We detected up to 9936 chemical features in a single product but found that each product has a rather unique chemical fingerprint. To tackle this chemical complexity, we used stepwise partial least squares regressions and prioritized and tentatively identified the chemical features associated with receptor activity. Our findings demonstrate that most plastic food packaging contains endocrine and metabolism disrupting chemicals. This shows that plastics are a relevant source of exposure to toxic chemicals and further supports the notion that plastic products designed for food contact cannot be considered safe. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=114 SRC="FIGDIR/small/559713v1_ufig1.gif" ALT="Figure 1"> View larger version (38K): org.highwire.dtl.DTLVardef@44be3borg.highwire.dtl.DTLVardef@1252a31org.highwire.dtl.DTLVardef@f522a2org.highwire.dtl.DTLVardef@1b4f8be_HPS_FORMAT_FIGEXP M_FIG C_FIG

pharmacology and toxicology↗

bioRxiv2022

PAMP-Induced secreted Peptide-Like 6 (PIPL6) functions as an amplifier of plant immune response through RLK7 and WRKY33 module

Plant peptide hormones are engaged in the regulation of plant developmental programs and immunity. PAMP-Induced Peptide (PIP) hormones are new class of signaling peptide with diverse functional roles in the regulation of plant development and stress responses. In this study, we have investigated the function of PAMP-Induced secreted Peptide-Like 6 (PIPL6) as an amplifier of plant immunity against necrotrophic fungal pathogens in Arabidopsis thaliana. We have applied an integrated omics approach to unveil the function and downstream signaling pathways initiated by PIPL6. PIPL6 is highly and transiently induced by treatment with different elicitors. Exogenous application of synthetic peptide designed from the C-terminal conserved domain of PIPL6 resulted in strong transcriptional induction of many genes involved in the regulation of plant immunity. Further gene expression analysis revealed that induction of marker genes by PIPL6 peptide requires the receptor-like kinase 7 (RLK7). Immunoblotting and gene expression analysis demonstrated that exogenous applications of PIPL6 peptide activates MAPK6, MAPK3, and WRKY33 module in an RLK7-dependent manner. The levels of salicylic acid, jasmonic acid, camalexin, and glucosinolates were differentially regulated in PIPL6 knock-down and overexpression lines challenged by necrotrophic pathogen Botrytis cinerea. Bioassays using the necrotrophic fungal pathogens Botrytis cinerea and Alternaria brassicae showed that pipl6 knock-down lines were more susceptible to these pathogens while PIPL6 overexpression lines exhibited enhanced resistance. Altogether, these results indicate that the PIPL6 peptide functions as a new damage-associated molecular pattern (DAMP) and acts as an amplifier of Arabidopsis immunity.

plant biology↗

bioRxiv2021

THESEUS1 modulates cell wall stiffness and abscisic acid production in Arabidopsis thaliana

Plant cells can be distinguished from animal cells by their cell walls and high turgor pressure. Although changes in turgor and stiffness of cell walls seem coordinated, we know little about the mechanism responsible for coordination. Evidence has accumulated that plants, like yeast, have a dedicated cell wall integrity maintenance mechanism. This mechanism monitors the functional integrity of the wall and maintains it through adaptive responses when cell wall damage occurs during growth, development, and interactions with the environment. The adaptive responses include osmo-sensitive-induction of phytohormone production, defence responses as well as changes in cell wall composition and structure. Here, we investigate how the cell wall integrity maintenance mechanism coordinates changes in cell wall stiffness and turgor in Arabidopsis thaliana. We show that the production of abscisic acid (ABA), the phytohormone modulating turgor pressure and responses to drought, depends on the presence of a functional cell wall. We find that the cell wall integrity sensor THESEUS1 modulates mechanical properties of walls, turgor loss point and ABA biosynthesis. We identify RECEPTOR-LIKE PROTEIN 12 as a new component of cell wall integrity maintenance controlling cell wall damage-induced jasmonic acid production. Based on the results we propose that THE1 is responsible for coordinating changes in turgor pressure and cell wall stiffness. Significance statementPlants need to constantly adapt to a changing environment. This includes responses to biotic and abiotic stress. Key elements influencing the response to abiotic stress are the plant cell walls surrounding all cells and the phytohormone abscisic acid, which influences turgor pressure in plants. Turgor pressure in plant cells is much higher than in animal cells and a key driver of plant growth and development. Here we investigate the mechanism regulating cell wall stiffness and coordinating changes in stiffness and turgor. We characterize key elements of the mechanism and dissect its mode of action. This knowledge will enable us to pursue novel approaches to improve plant resistance to drought stress, which is crucial in a rapidly changing environment.

plant biology↗