Drought poses a significant threat to global crop productivity and food security. In this study, we aimed to elucidate the impact of drought on transcriptional regulation and alternative splicing in barley (Hordeum vulgare), and to determine whether these transcriptomic alterations correlate with changes in hormonal profiles. We hypothesized that drought stress induces extensive reprogramming of gene expression, including alternative splicing events, and that these molecular responses are accompanied by tissue-specific shifts in hormone levels, ultimately underpinning adaptive responses in both leaves and roots. To test this, we performed RNA-seq and comprehensive hormone profiling on leaves and roots sampled at 25 days after planting under both optimal and drought conditions. Our analysis identified over 6,655 differentially expressed genes, with a substantial subset exhibiting differential alternative splicing. In leaves, drought primarily downregulated photosynthesis-related genes while upregulating pathways involved in water stress and abscisic acid (ABA) signaling. In contrast, roots displayed broader metabolic adjustments and significant isoform switching. Hormone analysis revealed marked ABA accumulation, particularly in roots, alongside organ-specific modulation of jasmonates and auxins. A limited assessment of the rhizosphere microbial community revealed low transcript abundance, underscoring the primacy of intrinsic plant responses. Collectively, these findings provide valuable insights into the multilayered adaptive strategies of barley under drought stress.

• Keywords
• Alternative splicing (AS), Barley, Drought, Hormones, Metatranscriptomics, Transcriptomics,
• MeSH
• Alternative Splicing MeSH
• Adaptation, Physiological * genetics   MeSH
• Stress, Physiological genetics   MeSH
• Hordeum * genetics   physiology   metabolism   MeSH
• Plant Roots * genetics   metabolism   MeSH
• Abscisic Acid metabolism   MeSH
• Plant Leaves * genetics   metabolism   MeSH
• Droughts * MeSH
• Gene Expression Regulation, Plant * MeSH
• Plant Growth Regulators * metabolism   MeSH
• Gene Expression Profiling MeSH
• Transcriptome * MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Abscisic Acid MeSH
• Plant Growth Regulators * MeSH

In response to environmental changes, plants continuously make architectural changes in order to optimize their growth and development. The regulation of plant branching, influenced by environmental conditions and affecting hormone balance and gene expression, is crucial for agronomic purposes due to its direct correlation with yield. Strigolactones (SL), the youngest class of phytohormones, function to shape the architecture of plants by inhibiting axillary outgrowth. Barley plants harboring the mutation in the HvDWARF14 (HvD14) gene, which encodes the SL-specific receptor, produce almost twice as many tillers as wild-type (WT) Sebastian plants. Here, through hormone profiling and comparison of transcriptomic and proteomic changes between 2- and 4-week-old plants of WT and hvd14 genotypes, we elucidate a regulatory mechanism that might affect the tillering of SL-insensitive plants. The analysis showed statistically significant increased cytokinin content and decreased auxin and abscisic acid content in 'bushy' hvd14 compared to WT, which aligns with the commonly known actions of these hormones regarding branching regulation. Further, transcriptomic and proteomic analysis revealed a set of differentially expressed genes (DEG) and abundant proteins (DAP), among which 11.6% and 14.6% were associated with phytohormone-related processes, respectively. Bioinformatics analyses then identified a series of potential SL-dependent transcription factors (TF), which may control the differences observed in the hvd14 transcriptome and proteome. Comparison to available Arabidopsis thaliana data implicates a sub-selection of these TF as being involved in the transduction of SL signal in both monocotyledonous and dicotyledonous plants.

• Keywords
• Hordeum vulgare, Branching, Phytohormone cross-talk, Strigolactones,
• MeSH
• Cytokinins metabolism   MeSH
• Heterocyclic Compounds, 3-Ring * MeSH
• Homeostasis MeSH
• Hordeum * growth & development   metabolism   MeSH
• Lactones * metabolism   MeSH
• Mutation MeSH
• Proteome analysis   MeSH
• Gene Expression Regulation, Plant MeSH
• Plant Growth Regulators * metabolism   MeSH
• Plant Proteins genetics   metabolism   MeSH
• Gene Expression Profiling MeSH
• Transcription Factors metabolism   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Cytokinins MeSH
• GR24 strigolactone MeSH Browser
• Heterocyclic Compounds, 3-Ring * MeSH
• Lactones * MeSH
• Proteome MeSH
• Plant Growth Regulators * MeSH
• Plant Proteins MeSH
• Transcription Factors MeSH

Wood of broad-leaf tree species is a valued source of renewable biomass for biorefinery and a target for genetic improvement efforts to reduce its recalcitrance. Glucuronoxylan (GX) plays a key role in recalcitrance through its interactions with cellulose and lignin. To reduce recalcitrance, we modified wood GX by expressing GH10 and GH11 endoxylanases from Aspergillus nidulans in hybrid aspen (Populus tremula L. × tremuloides Michx.) and targeting the enzymes to cell wall. The xylanases reduced tree height, modified cambial activity by increasing phloem and reducing xylem production, and reduced secondary wall deposition. Xylan molecular weight was decreased, and the spacing between acetyl and MeGlcA side chains was reduced in transgenic lines. The transgenic trees produced hypolignified xylem having thin secondary walls and deformed vessels. Glucose yields of enzymatic saccharification without pretreatment almost doubled indicating decreased recalcitrance. The transcriptomics, hormonomics and metabolomics data provided evidence for activation of cytokinin and ethylene signalling pathways, decrease in ABA levels, transcriptional suppression of lignification and a subset of secondary wall biosynthetic program, including xylan glucuronidation and acetylation machinery. Several candidate genes for perception of impairment in xylan integrity were detected. These candidates could provide a new target for uncoupling negative growth effects from reduced recalcitrance. In conclusion, our study supports the hypothesis that xylan modification generates intrinsic signals and evokes novel pathways regulating tree growth and secondary wall biosynthesis.

• Keywords
• Glucuronoxylan, fungal xylanases, lignocellulose, secondary cell wall, transgenic aspen, wood development,
• MeSH
• Aspergillus nidulans * genetics   physiology   MeSH
• Cell Wall * chemistry   metabolism   MeSH
• Wood * MeSH
• Endo-1,4-beta Xylanases metabolism   MeSH
• Populus * microbiology   physiology   MeSH
• Plant Cells MeSH
• Saccharin MeSH
• Trees physiology   MeSH
• Xylans * biosynthesis   genetics   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Endo-1,4-beta Xylanases MeSH
• Saccharin MeSH
• Xylans * MeSH

We have developed and validated a novel LC-MS/MS method for simultaneously analyzing amino acids, biogenic amines, and their acetylated and methylated derivatives in plants. This method involves a one-step extraction of 2-5 mg of lyophilized plant material followed by fractionation of different biogenic amine forms, and exploits an efficient combination of hydrophilic interaction liquid chromatography (HILIC), reversed phase (RP) chromatography with pre-column derivatization, and tandem mass spectrometry (MS). This approach enables high-throughput processing of plant samples, significantly reducing the time needed for analysis and its cost. We also present a new synthetic route for deuterium-labeled polyamines. The LC-MS/MS method was rigorously validated by quantifying levels of nitrogen-related metabolites in seedlings of seven plant species, including Arabidopsis, maize, and barley, all of which are commonly used model organisms in plant science research. Our results revealed substantial variations in the abundance of these metabolites between species, developmental stages, and growth conditions, particularly for the acetylated and methylated derivatives and the various polyamine fractions. However, the biological relevance of these plant metabolites is currently unclear. Overall, this work contributes significantly to plant science by providing a powerful analytical tool and setting the stage for future investigations into the functions of these nitrogen-related metabolites in plants.

• Keywords
• Acetylated amino acids, LC-MS/MS, acetylated biogenic amines, amino acids, biogenic amines, methylated amino acids, plant metabolism,
• MeSH
• Arabidopsis metabolism   growth & development   MeSH
• Chromatography, Liquid MeSH
• Nitrogen * metabolism   MeSH
• Hordeum metabolism   growth & development   MeSH
• Liquid Chromatography-Mass Spectrometry MeSH
• Zea mays metabolism   growth & development   MeSH
• Polyamines metabolism   analysis   MeSH
• Plants metabolism   MeSH
• Tandem Mass Spectrometry * methods   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Nitrogen * MeSH
• Polyamines MeSH

Plants in habitats with unpredictable conditions often have diversified bet-hedging strategies that ensure fitness over a wider range of variable environmental factors. A striking example is the diaspore (seed and fruit) heteromorphism that evolved to maximize species survival in Aethionema arabicum (Brassicaceae) in which external and endogenous triggers allow the production of two distinct diaspores on the same plant. Using this dimorphic diaspore model, we identified contrasting molecular, biophysical, and ecophysiological mechanisms in the germination responses to different temperatures of the mucilaginous seeds (M+ seed morphs), the dispersed indehiscent fruits (IND fruit morphs), and the bare non-mucilaginous M- seeds obtained by pericarp (fruit coat) removal from IND fruits. Large-scale comparative transcriptome and hormone analyses of M+ seeds, IND fruits, and M- seeds provided comprehensive datasets for their distinct thermal responses. Morph-specific differences in co-expressed gene modules in seeds, as well as in seed and pericarp hormone contents, identified a role of the IND pericarp in imposing coat dormancy by generating hypoxia affecting abscisic acid (ABA) sensitivity. This involved expression of morph-specific transcription factors, hypoxia response, and cell wall remodeling genes, as well as altered ABA metabolism, transport, and signaling. Parental temperature affected ABA contents and ABA-related gene expression and altered IND pericarp biomechanical properties. Elucidating the molecular framework underlying the diaspore heteromorphism can provide insight into developmental responses to globally changing temperatures.

• MeSH
• Brassicaceae * genetics   physiology   metabolism   MeSH
• Germination * genetics   physiology   MeSH
• Abscisic Acid metabolism   MeSH
• Fruit * genetics   physiology   growth & development   metabolism   MeSH
• Gene Expression Regulation, Plant * MeSH
• Plant Growth Regulators metabolism   MeSH
• Seeds * genetics   physiology   growth & development   metabolism   MeSH
• Temperature * MeSH
• Transcriptome genetics   MeSH
• Plant Dormancy genetics   physiology   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Abscisic Acid MeSH
• Plant Growth Regulators MeSH

BACKGROUND: Gaseous phytohormone ethylene levels are directly influenced by the production of its immediate non-volatile precursor 1-aminocyclopropane-1-carboxylic acid (ACC). Owing to the strongly acidic character of the ACC molecule, its quantification has been difficult to perform. Here, we present a simple and straightforward validated method for accurate quantification of not only ACC levels, but also major members of other important phytohormonal classes - auxins, cytokinins, jasmonic acid, abscisic acid and salicylic acid from the same biological sample. RESULTS: The presented technique facilitates the analysis of 15 compounds by liquid chromatography coupled with tandem mass spectrometry. It was optimized and validated for 10 mg of fresh weight plant material. The extraction procedure is composed of a minimal amount of necessary steps. Accuracy and precision were the basis for evaluating the method, together with process efficiency, recovery and matrix effects as validation parameters. The examined compounds comprise important groups of phytohormones, their active forms and some of their metabolites, including six cytokinins, four auxins, two jasmonates, abscisic acid, salicylic acid and 1-aminocyclopropane-1-carboxylic acid. The resulting method was used to examine their contents in selected Arabidopsis thaliana mutant lines. CONCLUSION: This profiling method enables a very straightforward approach for indirect ethylene study and explores how it interacts, based on content levels, with other phytohormonal groups in plants.

• Keywords
• 1-aminocyclopropane-1-carboxylic acid, ACC, Abscisic acid, Arabidopsis, Auxin, Cytokinin, Ethylene, Jasmonic acid, Liquid chromatography, Mass spectrometry, Plant hormones, Salicylic acid,
• Publication type
• Journal Article MeSH

Although the pesticide hexachlorocyclohexane (HCH) and its isomers have long been banned, their presence in the environment is still reported worldwide. In this study, we investigated the bioaccumulation potential of α, β, and δ hexachlorocyclohexane (HCH) isomers in black alder saplings (Alnus glutinosa) to assess their environmental impact. Each isomer, at a concentration of 50 mg/kg, was individually mixed with soil, and triplicate setups, including a control without HCH, were monitored for three months with access to water. Gas chromatography-mass spectrometry revealed the highest concentrations of HCH isomers in roots, decreasing towards branches and leaves, with δ-HCH exhibiting the highest uptake (roots-14.7 µg/g, trunk-7.2 µg/g, branches-1.53 µg/g, leaves-1.88 µg/g). Interestingly, α-HCH was detected in high concentrations in β-HCH polluted soil. Phytohormone analysis indicated altered cytokinin, jasmonate, abscisate, and gibberellin levels in A. glutinosa in response to HCH contamination. In addition, amplicon 16S rRNA sequencing was used to study the rhizosphere and soil microbial community. While rhizosphere microbial populations were generally similar in all HCH isomer samples, Pseudomonas spp. decreased across all HCH-amended samples, and Tomentella dominated in β-HCH and control rhizosphere samples but was lowest in δ-HCH samples.

• MeSH
• Biodegradation, Environmental MeSH
• Hexachlorocyclohexane analysis   MeSH
• Soil Pollutants * analysis   MeSH
• Alnus * MeSH
• Soil MeSH
• RNA, Ribosomal, 16S genetics   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• beta-hexachlorocyclohexane MeSH Browser
• delta-hexachlorocyclohexane MeSH Browser
• Hexachlorocyclohexane MeSH
• Soil Pollutants * MeSH
• Soil MeSH
• RNA, Ribosomal, 16S MeSH

The transition from seed to seedling represents a critical developmental step in the life cycle of higher plants, dramatically affecting plant ontogenesis and stress tolerance. The release from dormancy to acquiring germination ability is defined by a balance of phytohormones, with the substantial contribution of abscisic acid (ABA), which inhibits germination. We studied the embryonic axis of Pisum sativum L. before and after radicle protrusion. Our previous work compared RNA sequencing-based transcriptomics in the embryonic axis isolated before and after radicle protrusion. The current study aims to analyze ABA-dependent gene regulation during the transition of the embryonic axis from the germination to post-germination stages. First, we determined the levels of abscisates (ABA, phaseic acid, dihydrophaseic acid, and neo-phaseic acid) using ultra-high-performance liquid chromatography-tandem mass spectrometry. Second, we made a detailed annotation of ABA-associated genes using RNA sequencing-based transcriptome profiling. Finally, we analyzed the DNA methylation patterns in the promoters of the PsABI3, PsABI4, and PsABI5 genes. We showed that changes in the abscisate profile are characterized by the accumulation of ABA catabolites, and the ABA-related gene profile is accompanied by the upregulation of genes controlling seedling development and the downregulation of genes controlling water deprivation. The expression of ABI3, ABI4, and ABI5, which encode crucial transcription factors during late maturation, was downregulated by more than 20-fold, and their promoters exhibited high levels of methylation already at the late germination stage. Thus, although ABA remains important, other regulators seems to be involved in the transition from seed to seedling.

• Keywords
• ABA-associated genes, DNA methylation, Pisum sativum L., abscisic acid, embryonic axis, seed-to-seedling transition,
• Publication type
• Journal Article MeSH

The carnivorous plants in the order Caryophyllales co-opted jasmonate signalling from plant defence to botanical carnivory. However, carnivorous plants have at least 11 independent origins, and here we ask whether jasmonate signalling has been co-opted repeatedly in different evolutionary lineages. We experimentally wounded and fed the carnivorous plants Sarracenia purpurea (order Ericales), Cephalotus follicularis (order Oxalidales), Drosophyllum lusitanicum (order Caryophyllales), and measured electrical signals, phytohormone tissue level, and digestive enzymes activity. Coronatine was added exogenously to confirm the role of jasmonates in the induction of digestive process. Immunodetection of aspartic protease and proteomic analysis of digestive fluid was also performed. We found that prey capture induced accumulation of endogenous jasmonates only in D. lusitanicum, in accordance with increased enzyme activity after insect prey or coronatine application. In C. follicularis, the enzyme activity was constitutive while in S. purpurea was regulated by multiple factors. Several classes of digestive enzymes were identified in the digestive fluid of D. lusitanicum. Although carnivorous plants from different evolutionary lineages use the same digestive enzymes, the mechanism of their regulation differs. All investigated genera use jasmonates for their ancient role, defence, but jasmonate signalling has been co-opted for botanical carnivory only in some of them.

• Keywords
• Aspartic protease, carnivorous plant, digestive enzymes, electrical signal, jasmonic acid, phytohormone, plant defence, wounding,
• MeSH
• Carnivory * MeSH
• Carnivorous Plant * MeSH
• Proteomics MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• coronatine MeSH Browser
• jasmonic acid MeSH Browser

Brassinosteroids (BRs) are key phytohormones involved in the regulation of major processes of cell metabolism that guide plant growth. In the past decades, new evidence has made it clear that BRs also play a key role in the orchestration of plant responses to many abiotic and biotic stresses. In the present work, we analyzed the impact of foliar treatment with 24-epicastasterone (ECS) on the endogenous content of major phytohormones (auxins, salicylic acid, jasmonic acid, and abscisic acid) and their intermediates in soybean leaves 7 days following the treatment. Changes in the endogenous content of phytohormones have been identified and quantified by LC/MS. The obtained results point to a clear role of ECS in the upregulation of auxin content (indole-3-acetic acid, IAA) and downregulation of salicylic, jasmonic, and abscisic acid levels. These data confirm that under optimal conditions, ECS in tested concentrations of 0.25 µM and 1 µM might promote growth in soybeans by inducing auxin contents. Benzoic acid (a precursor of salicylic acid (SA)), but not SA itself, has also been highly accumulated under ECS treatment, which indicates an activation of the adaptation strategies of cell metabolism to possible environmental challenges.

• Keywords
• 24-epicastasterone, auxins, hormones, salicylic acid, soybean,
• Publication type
• Journal Article MeSH