The genomes of charophyte green algae, close relatives of land plants, typically do not show signs of developmental regulation by phytohormones. However, scattered reports of endogenous phytohormone production in these organisms exist. We performed a comprehensive analysis of multiple phytohormones in Viridiplantae, focusing mainly on charophytes. We show that auxin, salicylic acid, ethylene and tRNA-derived cytokinins including cis-zeatin are found ubiquitously in Viridiplantae. By contrast, land plants but not green algae contain the trans-zeatin type cytokinins as well as auxin and cytokinin conjugates. Charophytes occasionally produce jasmonates and abscisic acid, whereas the latter is detected consistently in land plants. Several phytohormones are excreted into the culture medium, including auxin by charophytes and cytokinins and salicylic acid by Viridiplantae in general. We note that the conservation of phytohormone biosynthesis and signaling pathways known from angiosperms does not match the capacity for phytohormone biosynthesis in Viridiplantae. Our phylogenetically guided analysis of established algal cultures provides an important insight into phytohormone biosynthesis and metabolism across Streptophyta.

• MeSH
• biologická evoluce MeSH
• Chlorophyta metabolismus   genetika   MeSH
• cyklopentany metabolismus   MeSH
• cytokininy * metabolismus   MeSH
• ethyleny metabolismus   MeSH
• fylogeneze * MeSH
• kyselina abscisová metabolismus   MeSH
• kyselina salicylová metabolismus   MeSH
• kyseliny indoloctové * metabolismus   MeSH
• oxylipiny metabolismus   MeSH
• regulace genové exprese u rostlin MeSH
• regulátory růstu rostlin * metabolismus   MeSH
• signální transdukce MeSH
• Viridiplantae metabolismus   genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• cyklopentany MeSH
• cytokininy * MeSH
• ethylene MeSH Prohlížeč
• ethyleny MeSH
• jasmonic acid MeSH Prohlížeč
• kyselina abscisová MeSH
• kyselina salicylová MeSH
• kyseliny indoloctové * MeSH
• oxylipiny MeSH
• regulátory růstu rostlin * MeSH

Seasonal dynamics of root growth play an important role in large-scale ecosystem processes; they are largely governed by growth regulatory compounds and influenced by environmental conditions. Yet, our knowledge about physiological drivers of root growth is mostly limited to laboratory-based studies on model plant species. We sampled root tips of Eriophorum vaginatum and analyzed their auxin concentrations and meristem lengths biweekly over a growing season in situ in a subarctic peatland, both in surface soil and at the permafrost thawfront. Auxin concentrations were almost five times higher in surface than in thawfront soils and increased over the season, especially at the thawfront. Surprisingly, meristem length showed an opposite pattern and was almost double in thawfront compared with surface soils. Meristem length increased from peak to late season in the surface soils but decreased at the thawfront. Our study of in situ seasonal dynamics in root physiological parameters illustrates the potential for physiological methods to be applied in ecological studies and emphasizes the importance of in situ measurements. The strong effect of root location and the unexpected opposite patterns of meristem length and auxin concentrations likely show that auxin actively governs root growth to ensure a high potential for nutrient uptake at the thawfront.

• Klíčová slova
• Eriophorum vaginatum, auxin, meristem length, permafrost, root growth, root phenology,
• MeSH
• ekosystém MeSH
• kořeny rostlin metabolismus   MeSH
• kyseliny indoloctové farmakologie   MeSH
• meristém * MeSH
• proteiny huseníčku * metabolismus   MeSH
• půda MeSH
• regulace genové exprese u rostlin MeSH
• roční období MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• kyseliny indoloctové MeSH
• proteiny huseníčku * MeSH
• půda MeSH

Polar auxin transport in the Arabidopsis (Arabidopsis thaliana) root tip maintains high auxin levels around the stem cell niche that gradually decrease in dividing cells but increase again once they transition toward differentiation. Protophloem differentiates earlier than other proximal tissues and employs a unique auxin "canalization" machinery that is thought to balance auxin efflux with retention. It consists of a proposed activator of PIN-FORMED (PIN) auxin efflux carriers, the cAMP-, cGMP- and Calcium-dependent (AGC) kinase PROTEIN KINASE ASSOCIATED WITH BRX (PAX); its inhibitor, BREVIS RADIX (BRX); and PHOSPHATIDYLINOSITOL-4-PHOSPHATE-5-KINASE (PIP5K) enzymes, which promote polar PAX and BRX localization. Because of a dynamic PAX-BRX-PIP5K interplay, the net cellular output of this machinery remains unclear. In this study, we deciphered the dosage-sensitive regulatory interactions among PAX, BRX, and PIP5K by their ectopic expression in developing xylem vessels. The data suggest that the dominant collective output of the PAX-BRX-PIP5K module is a localized reduction in PIN abundance. This requires PAX-stimulated clathrin-mediated PIN endocytosis upon site-specific phosphorylation, which distinguishes PAX from other AGC kinases. An ectopic assembly of the PAX-BRX-PIP5K module is sufficient to cause cellular auxin retention and affects root growth vigor by accelerating the trajectory of xylem vessel development. Our data thus provide direct evidence that local manipulation of auxin efflux alters the timing of cellular differentiation in the root.

• MeSH
• Arabidopsis * metabolismus   genetika   růst a vývoj   MeSH
• biologický transport MeSH
• fosfotransferasy s alkoholovou skupinou jako akceptorem metabolismus   genetika   MeSH
• kořeny rostlin metabolismus   růst a vývoj   genetika   MeSH
• kyseliny indoloctové * metabolismus   MeSH
• membránové transportní proteiny metabolismus   genetika   MeSH
• protein-serin-threoninkinasy * MeSH
• proteiny huseníčku * metabolismus   genetika   MeSH
• regulace genové exprese u rostlin MeSH
• xylém metabolismus   růst a vývoj   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• AT1G66150 protein, Arabidopsis MeSH Prohlížeč
• BREVIS RADIX protein, Arabidopsis MeSH Prohlížeč
• fosfotransferasy s alkoholovou skupinou jako akceptorem MeSH
• kyseliny indoloctové * MeSH
• membránové transportní proteiny MeSH
• protein-serin-threoninkinasy * MeSH
• proteiny huseníčku * MeSH

2,4-D is a broadly used auxin herbicide. The presence of the 2,4-D synthetic auxin in the medium is imperative for long-term BY-2 tobacco suspension viability. The precise mechanism of this symbiosis of the suspension and the synthetic auxin remains unclear. Our goal was to study the hormonal regulation of the growth of the cell suspension; and to describe the experiments clarifying the interaction between the chosen growth regulators and phytohormones on the cellular level, specifically between the 2,4-D synthetic auxin and the native stress phytohormone - ethylene. This study examined the influence of low 2,4-D concentrations stimulating cell growth in vitro as well as the influence of high herbicide concentrations on the model tobacco BY-2 suspension. The culture took 6 days. Different parameters were evaluated, including the influence of different 2,4-D concentrations on the production of the phytohormone ethylene and its precursor 1-Aminocyclopropane-1-carboxylic acid (ACC) in the tobacco cells. The content of 2,4-D in the cells and the medium was established. The observations of the morphological changes showed that a heavy impregnation of the cell walls taking place depending on the concentration of 2,4-D. A dramatic increase in protective polysaccharides and a remodulation of the cell walls by the formation of a pectin shield in artificial conditions were expected and observed. At the same time, massive production of the stress phytohormone ethylene took place, and, because of that, plant mutagenicity, anomalous tumour-type proliferation growth, and the production of supercells were observed. The hypothesis of the protective shield is discussed.

• Klíčová slova
• 2,4- dichlorophenoxyacetic acid, 2,4-D, BY-2 cell suspension, Ethylene, Pectin shield, Plant mutagenicity,
• MeSH
• ethyleny MeSH
• herbicidy * farmakologie   MeSH
• kyselina 2,4-dichlorfenoxyoctová farmakologie   MeSH
• kyseliny indoloctové MeSH
• regulace genové exprese u rostlin MeSH
• regulátory růstu rostlin farmakologie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• ethylene MeSH Prohlížeč
• ethyleny MeSH
• herbicidy * MeSH
• kyselina 2,4-dichlorfenoxyoctová MeSH
• kyseliny indoloctové MeSH
• regulátory růstu rostlin MeSH

Brassinosteroids are steroidal phytohormones that regulate plant development and physiology, including adaptation to environmental stresses. Brassinosteroids are synthesized in the cell interior but bind receptors at the cell surface, necessitating a yet to be identified export mechanism. Here, we show that a member of the ATP-binding cassette (ABC) transporter superfamily, ABCB19, functions as a brassinosteroid exporter. We present its structure in both the substrate-unbound and the brassinosteroid-bound states. Bioactive brassinosteroids are potent activators of ABCB19 ATP hydrolysis activity, and transport assays showed that ABCB19 transports brassinosteroids. In Arabidopsis thaliana, ABCB19 and its close homolog, ABCB1, positively regulate brassinosteroid responses. Our results uncover an elusive export mechanism for bioactive brassinosteroids that is tightly coordinated with brassinosteroid signaling.

• MeSH
• ABC transportéry * chemie   genetika   metabolismus   MeSH
• adenosintrifosfát metabolismus   MeSH
• Arabidopsis * genetika   metabolismus   MeSH
• brassinosteroidy * metabolismus   MeSH
• konformace proteinů MeSH
• kyseliny indoloctové metabolismus   MeSH
• proteiny huseníčku * chemie   genetika   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• ABC transportéry * MeSH
• ABCB19 protein, Arabidopsis MeSH Prohlížeč
• adenosintrifosfát MeSH
• brassinosteroidy * MeSH
• kyseliny indoloctové MeSH
• proteiny huseníčku * MeSH

The nuclear TIR1/AFB-Aux/IAA auxin pathway plays a crucial role in regulating plant growth and development. Specifically, the IAA17/AXR3 protein participates in Arabidopsis thaliana root development, response to auxin and gravitropism. However, the mechanism by which AXR3 regulates cell elongation is not fully understood. We combined genetical and cell biological tools with transcriptomics and determination of auxin levels and employed live cell imaging and image analysis to address how the auxin response pathways influence the dynamics of root growth. We revealed that manipulations of the TIR1/AFB-Aux/IAA pathway rapidly modulate root cell elongation. While inducible overexpression of the AXR3-1 transcriptional inhibitor accelerated growth, overexpression of the dominant activator form of ARF5/MONOPTEROS inhibited growth. In parallel, AXR3-1 expression caused loss of auxin sensitivity, leading to transcriptional reprogramming, phytohormone signaling imbalance and increased levels of auxin. Furthermore, we demonstrated that AXR3-1 specifically perturbs nuclear auxin signaling, while the rapid auxin response remains functional. Our results shed light on the interplay between the nuclear and cytoplasmic auxin pathways in roots, revealing their partial independence but also the dominant role of the nuclear auxin pathway during the gravitropic response of Arabidopsis thaliana roots.

• Klíčová slova
• Arabidopsis thaliana, ARF5/MP, AXR3-1, IAA17/AXR3, auxin, cell elongation, cytoplasmic auxin pathway, nuclear auxin pathway,
• MeSH
• Arabidopsis * metabolismus   MeSH
• kořeny rostlin metabolismus   MeSH
• kyseliny indoloctové metabolismus   MeSH
• proteiny huseníčku * metabolismus   MeSH
• regulace genové exprese u rostlin MeSH
• regulátory růstu rostlin metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• AXR3 protein, Arabidopsis MeSH Prohlížeč
• kyseliny indoloctové MeSH
• proteiny huseníčku * MeSH
• regulátory růstu rostlin MeSH

Microalgae-derived biostimulants provide an eco-friendly biotechnology for improving crop productivity. The strategy of circular economy includes reducing biomass production costs of new and robust microalgae strains grown in nutrient-rich wastewater and mixotrophic culture where media is enriched with organic carbon. In this study, Chlorella sorokiniana was grown in 100 l bioreactors under sub-optimal conditions in a greenhouse. A combination of batch and semi-continuous cultivation was used to investigate the growth, plant hormone and biostimulating effect of biomass grown in diluted pig manure and in nutrient medium supplemented with Na-acetate. C. sorokiniana tolerated the low light (sum of PAR 0.99 ± 0.18 mol/photons/(m2/day)) and temperature (3.7-23.7° C) conditions to maintain a positive growth rate and daily biomass productivity (up to 149 mg/l/day and 69 mg/l/day dry matter production in pig manure and Na-acetate supplemented cultures respectively). The protein and lipid content was significantly higher in the biomass generated in batch culture and dilute pig manure (1.4x higher protein and 2x higher lipid) compared to the Na-acetate enriched culture. Auxins indole-3-acetic acid (IAA) and 2-oxindole-3-acetic acid (oxIAA) and salicylic acid (SA) were present in the biomass with significantly higher auxin content in the biomass generated using pig manure (> 350 pmol/g DW IAA and > 84 pmol/g DW oxIAA) compared to cultures enriched with Na-acetate and batch cultures (< 200 pmol/g DW IAA and < 27 pmol/g DW oxIAA). No abscisic acid and jasmonates were detected. All samples had plant biostimulating activity measured in the mungbean rooting bioassay with the Na-acetate supplemented biomass eliciting higher rooting activity (equivalent to 1-2 mg/l IBA) compared to the pig manure (equivalent to 0.5-1 mg/l IBA) and batch culture (equivalent to water control) generated biomass. Thus C. sorokiniana MACC-728 is a robust new strain for biotechnology, tolerating low light and temperature conditions. The strain can adapt to alternative nutrient (pig manure) and carbon (acetate) sources with the generated biomass having a high auxin concentration and plant biostimulating activity detected with the mungbean rooting bioassay.

• Klíčová slova
• Auxin, Low light, Low temperature, Proteins, Rooting activity, Salicylic acid,
• MeSH
• biomasa MeSH
• Chlorella * MeSH
• hnůj MeSH
• kyselina octová metabolismus   MeSH
• kyseliny indoloctové metabolismus   MeSH
• mikrořasy * metabolismus   MeSH
• prasata MeSH
• uhlík metabolismus   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• hnůj MeSH
• kyselina octová MeSH
• kyseliny indoloctové MeSH
• uhlík MeSH

Waterlogging leads to hypoxic conditions in the root zone that subsequently cause systemic adaptive responses in the shoot, including leaf epinasty. Waterlogging-induced epinasty in tomato has long been ascribed to the coordinated action of ethylene and auxins. However, other hormonal signals have largely been neglected, despite evidence of their importance in leaf posture control. To cover a large group of growth regulators, we performed a tissue-specific and time-dependent hormonomics analysis. This revealed that multiple hormones are differentially affected throughout a 48 h waterlogging treatment, and that leaf age determines hormone homeostasis and modulates their changes during waterlogging. In addition, we distinguished early hormonal signals that contribute to fast responses to oxygen deprivation from those that potentially sustain the waterlogging response. We found that abscisic acid (ABA) levels peak in petioles within the first 12 h of the treatment, while its precursors only increase much later, suggesting that ABA transport is altered. At the same time, cytokinins (CKs) and their derivatives drastically decline during waterlogging in leaves of all ages. This drop in CKs possibly releases the inhibition of ethylene- and auxin-mediated cell elongation to establish epinastic bending. Auxins themselves rise substantially in the petiole of mature leaves, but mostly after 48 h of root hypoxia. Based on our hormone profiling, we propose that ethylene and ABA might act synergistically as an early signal to induce epinasty, while the balance of indole-3-acetic acid and CKs in the petiole ultimately regulates differential growth.

• Klíčová slova
• Abscisic acid, cytokinins, epinasty, hypoxia, plant hormones, tomato, waterlogging,
• MeSH
• cytokininy MeSH
• ethyleny farmakologie   MeSH
• hormony MeSH
• kyselina abscisová MeSH
• kyseliny indoloctové farmakologie   MeSH
• listy rostlin MeSH
• regulátory růstu rostlin fyziologie   MeSH
• Solanum lycopersicum * MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• cytokininy MeSH
• ethylene MeSH Prohlížeč
• ethyleny MeSH
• hormony MeSH
• kyselina abscisová MeSH
• kyseliny indoloctové MeSH
• regulátory růstu rostlin MeSH

The plant-signaling molecule auxin triggers fast and slow cellular responses across land plants and algae. The nuclear auxin pathway mediates gene expression and controls growth and development in land plants, but this pathway is absent from algal sister groups. Several components of rapid responses have been identified in Arabidopsis, but it is unknown if these are part of a conserved mechanism. We recently identified a fast, proteome-wide phosphorylation response to auxin. Here, we show that this response occurs across 5 land plant and algal species and converges on a core group of shared targets. We found conserved rapid physiological responses to auxin in the same species and identified rapidly accelerated fibrosarcoma (RAF)-like protein kinases as central mediators of auxin-triggered phosphorylation across species. Genetic analysis connects this kinase to both auxin-triggered protein phosphorylation and rapid cellular response, thus identifying an ancient mechanism for fast auxin responses in the green lineage.

• Klíčová slova
• RAF kinase, auxin, plant evolution, protein phosphorylation,
• MeSH
• Arabidopsis genetika   metabolismus   MeSH
• bílkoviny řas metabolismus   MeSH
• fosforylace MeSH
• kyseliny indoloctové metabolismus   MeSH
• proteinkinasy metabolismus   MeSH
• regulace genové exprese u rostlin MeSH
• rostlinné proteiny metabolismus   MeSH
• rostliny metabolismus   MeSH
• signální transdukce * MeSH
• vyšší rostliny * metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• bílkoviny řas MeSH
• kyseliny indoloctové MeSH
• proteinkinasy MeSH
• rostlinné proteiny MeSH

In situ separation and visualization of synthetic and naturally occurring isomers from heterogeneous plant tissues, especially when they share similar molecular structures, are a challenging task. In this study, we combined the ion mobility separation with desorption electrospray ionization mass spectrometry imaging (DESI-IM-MSI) to achieve a direct separation and visualization of two synthetic auxin derivatives, auxinole and its structural isomer 4pTb-MeIAA, as well as endogenous auxins from Arabidopsis samples. Distinct distribution of these synthetic isomers and endogenous auxins in Arabidopsis primary roots and hypocotyls was achieved in the same imaging analysis from both individually treated and cotreated samples. We also observed putative metabolites of synthetic auxin derivatives, i.e. auxinole amino acid conjugates and hydrolysed 4pTb-MeIAA product - 4pTb-IAA, based on their unique drifting ion intensity patterns. Furthermore, DESI-IM-MSI-revealed abundance of endogenous auxins and synthetic isomers was validated by liquid chromatography-mass spectrometry (LC-MS). Our results demonstrate that DESI-IM-MSI could be used as a robust technique for detecting endogenous and exogenous isomers and provide a spatiotemporal evaluation of hormonomics profiles in plants.

• Klíčová slova
• Auxin, Desorption electrospray ionization, Ion mobility, Isomer, Mass spectrometry imaging, Metabolite,
• MeSH
• Arabidopsis * MeSH
• hmotnostní spektrometrie s elektrosprejovou ionizací metody   MeSH
• isomerie MeSH
• kyseliny indoloctové analýza   MeSH
• molekulární struktura MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• kyseliny indoloctové MeSH