Perception and transduction of temperature changes result in altered growth enabling plants to adapt to increased ambient temperature. While PHYTOCHROME-INTERACTING FACTOR4 (PIF4) has been identified as a major ambient temperature signaling hub, its upstream regulation seems complex and is poorly understood. Here, we exploited natural variation for thermo-responsive growth in Arabidopsis thaliana using quantitative trait locus (QTL) analysis. We identified GIRAFFE2.1, a major QTL explaining ~18% of the phenotypic variation for temperature-induced hypocotyl elongation in the Bay-0 x Sha recombinant inbred line population. Transgenic complementation demonstrated that allelic variation in the circadian clock regulator EARLY FLOWERING3 (ELF3) is underlying this QTL. The source of variation could be allocated to a single nucleotide polymorphism in the ELF3 coding region, resulting in differential expression of PIF4 and its target genes, likely causing the observed natural variation in thermo-responsive growth. In combination with other recent studies, this work establishes the role of ELF3 in the ambient temperature signaling network. Natural variation of ELF3-mediated gating of PIF4 expression during nightly growing periods seems to be affected by a coding sequence quantitative trait nucleotide that confers a selective advantage in certain environments. In addition, natural ELF3 alleles seem to differentially integrate temperature and photoperiod cues to induce architectural changes. Thus, ELF3 emerges as an essential coordinator of growth and development in response to diverse environmental cues and implicates ELF3 as an important target of adaptation.

Background Global increase in ambient temperatures constitute a significant challenge to wild and cultivated plant species. Forward genetic analyses of individual temperature-responsive traits have resulted in the identification of several signaling and response components. However, a comprehensive knowledge about temperature sensitivity of different developmental stages and the contribution of natural variation is still scarce and fragmented at best.Results Here, we systematically analyze thermomorphogenesis throughout a complete life cycle in ten natural Arabidopsis thaliana accessions grown in four different temperatures ranging from 16 to 28 °C. We used Q10, GxE, phenotypic divergence and correlation analyses to assess temperature sensitivity and genotype effects of more than 30 morphometric and developmental traits representing five phenotype classes. We found that genotype and temperature differentially affected plant growth and development with variing strengths. Furthermore, overall correlations among phenotypic temperature responses was relatively low which seems to be caused by differential capacities for temperature adaptations of individual accessions.Conclusion Genotype-specific temperature responses may be attractive targets for future forward genetic approaches and accession-specific thermomorphogenesis maps may aid the assessment of functional relevance of known and novel regulatory components.

The historic developmental hourglass concept depicts the convergence of animal embryos to a common form during the phylotypic period. Recently, it has been shown that a transcriptomic hourglass is associated with this morphological pattern, consistent with the idea of underlying selective constraints due to intense molecular interactions during body plan establishment. Although plants do not exhibit a morphological hourglass during embryogenesis, a transcriptomic hourglass has nevertheless been identified in the model plant Arabidopsis thaliana. Here, we investigated whether plant hourglass patterns are also found post-embryonically. We found that the two main phase changes during the life cycle of Arabidopsis, from embryonic to vegetative and from vegetative to reproductive development, are associated with transcriptomic hourglass patterns. In contrast, flower development, a process dominated by organ formation, is not. This suggests that plant hourglass patterns are decoupled from organogenesis and body plan establishment. Instead, they may reflect general transitions through organizational checkpoints.

Crystal structure data of cation-dependent catechol O-methyltransferases (COMTs) from mammals and related caffeoyl coenzyme A OMTs (CCoAOMTs) from plants have suggested operative molecular mechanisms. These include bivalent cations that facilitate deprotonation of vicinal aromatic dihydroxy systems and illustrate a conserved arrangement of hydroxyl and carboxyl ligands consistent with the requirements of a metal-activated catalytic mechanism. The general concept of metal-dependent deprotonation via a complexed aspartate is only one part of a more pronounced proton relay, as shown by semiempirical and DFT quantum mechanical calculations and experimental validations. A previously undetected catalytic triad, consisting of Lys157-Asn181-Asp228 residues is required for complete methyl transfer in case of a cation-dependent phenylpropanoid and flavonoid OMT, as described in this report. This triad appears essential for efficient methyl transfer to catechol-like hydroxyl group in phenolics. The observation is consistent with a catalytic lysine in the case of mammalian COMTs, but jettisons existing assumptions on the initial abstraction of the meta-hydroxyl proton to the metal stabilizing Asp154 (PFOMT) or comparable Asp-carboxyl groups in type of cation-dependent enzymes in plants. The triad is conserved among all characterized plant CCoAOMT-like enzymes, which are required not only for methylation of soluble phenylpropanoids like coumarins or monolignol monomers, but is also present in the similar microbial and mammalian cation-dependent enzymes which methylate a comparable set of substrates.

SOLUTIONS (2013 to 2018) is a European Union Seventh Framework Programme Project (EU-FP7). The project aims to deliver a conceptual framework to support the evidence-based development of environmental policies with regard to water quality. SOLUTIONS will develop the tools for the identification, prioritisation and assessment of those water contaminants that may pose a risk to ecosystems and human health. To this end, a new generation of chemical and effect-based monitoring tools is developed and integrated with a full set of exposure, effect and risk assessment models. SOLUTIONS attempts to address legacy, present and future contamination by integrating monitoring and modelling based approaches with scenarios on future developments in society, economy and technology and thus in contamination. The project follows a solutions-oriented approach by addressing major problems of water and chemicals management and by assessing abatement options. SOLUTIONS takes advantage of the access to the infrastructure necessary to investigate the large basins of the Danube and Rhine as well as relevant Mediterranean basins as case studies, and puts major efforts on stakeholder dialogue and support. Particularly, the EU Water Framework Directive (WFD) Common Implementation Strategy (CIS) working groups, International River Commissions, and water works associations are directly supported with consistent guidance for the early detection, identification, prioritisation, and abatement of chemicals in the water cycle. SOLUTIONS will give a specific emphasis on concepts and tools for the impact and risk assessment of complex mixtures of emerging pollutants, their metabolites and transformation products. Analytical and effect-based screening tools will be applied together with ecological assessment tools for the identification of toxicants and their impacts. The SOLUTIONS approach is expected to provide transparent and evidence-based candidates or River Basin Specific Pollutants in the case study basins and to assist future review of priority pollutants under the WFD as well as potential abatement options.

Carnosic acid (CA) is a phenolic diterpene with anti-tumour, anti-diabetic, antibacterial and neuroprotective properties that is produced by a number of species from several genera of the Lamiaceae family, including Salvia fruticosa (Cretan sage) and Rosmarinus officinalis (Rosemary). To elucidate CA biosynthesis, glandular trichome transcriptome data of S. fruticosa were mined for terpene synthase genes. Two putative diterpene synthase genes, namely SfCPS and SfKSL, showing similarities to copalyl diphosphate synthase and kaurene synthase-like genes, respectively, were isolated and functionally characterized. Recombinant expression in Escherichia coli followed by in vitro enzyme activity assays confirmed that SfCPS is a copalyl diphosphate synthase. Coupling of SfCPS with SfKSL, both in vitro and in yeast, resulted in the synthesis miltiradiene, as confirmed by 1D and 2D NMR analyses (1H, 13C, DEPT, COSY H-H, HMQC and HMBC). Coupled transient in vivo assays of SfCPS and SfKSL in Nicotiana benthamiana further confirmed production of miltiradiene in planta. To elucidate the subsequent biosynthetic step, RNA-Seq data of S. fruticosa and R. officinalis were searched for cytochrome P450 (CYP) encoding genes potentially involved in the synthesis of the first phenolic compound in the CA pathway, ferruginol. Three candidate genes were selected, SfFS, RoFS1 and RoFS2. Using yeast and N. benthamiana expression systems, all three where confirmed to be coding for ferruginol synthases, thus revealing the enzymatic activities responsible for the first three steps leading to CA in two Lamiaceae genera.

Hypoglycin A (HGA) in seeds of Acer spp. is suspected to cause seasonal pasture myopathy in North America and equine atypical myopathy (AM) in Europe, fatal diseases in horses on pasture. In previous studies, this suspicion was substantiated by the correlation of seed HGA content with the concentrations of toxic metabolites in urine and serum (MCPA-conjugates) of affected horses. However, seed sampling was conducted after rather than during an outbreak of the disease. The aim of this study was to further confirm the causality between HGA occurrence and disease outbreak by seed sampling during an outbreak and the determination of i) HGA in seeds and of ii) HGA and MCPA-conjugates in urine and serum of diseased horses. Furthermore, cograzing healthy horses, which were present on AM affected pastures, were also investigated. AM-pastures in Germany were visited to identify seeds of Acer pseudoplatanus and serum (n = 8) as well as urine (n = 6) from a total of 16 diseased horses were analyzed for amino acid composition by LC-ESI-MS/MS, with a special focus on the content of HGA. Additionally, the content of its toxic metabolite was measured in its conjugated form in body fluids (UPLC-MS/MS). The seeds contained 1.7–319.8 μg HGA/g seed. The content of HGA in serum of affected horses ranged from 387.8–8493.8 μg/L (controls < 10 μg/L), and in urine from 143.8–926.4 μg/L (controls < 10 μg/L), respectively. Healthy cograzing horses on AM-pastures showed higher serum (108.8 ± 83.76 μg/L) and urine concentrations (26.9 ± 7.39 μg/L) compared to control horses, but lower concentrations compared to diseased horses. The range of MCPA-carnitine and creatinine concentrations found in diseased horses in serum and urine were 0.17–0.65 mmol/L (controls < 0.01), and 0.34–2.05 μmol/mmoL (controls < 0.001), respectively. MCPA-glycine levels in urine of cograzing horses were higher compared to controls. Thus, the causal link between HGA intoxication and disease outbreak could be further substantiated, and the early detection of HGA in cograzing horses, which are clinically normal, might be a promising step in prophylaxis.

The androgen receptor is an important pharmaceutical target for a variety of diseases. This paper presents an in silico/in vitro screening procedure to identify new androgen receptor ligands. The two-step virtual screening procedure uses a three-dimensional pharmacophore model and a docking/scoring routine. About 39,000 filtered compounds were docked with PLANTS and scored by Chemplp. Subsequent to virtual screening, 94 compounds, including 28 steroidal and 66 nonsteroidal compounds, were tested by an androgen receptor fluorescence polarization ligand displacement assay. As a result, 30 compounds were identified that show a relative binding affinity of more than 50% in comparison to 100 nM dihydrotestosterone and were classified as androgen receptor binders. For 11 androgen receptor binders of interest IC50 and Ki values were determined. The compound with the highest affinity exhibits a Ki value of 10.8 nM. Subsequent testing of the 11 compounds in a PC-3 and LNCaP multi readout proliferation assay provides insights into the potential mode of action. Further steroid receptor ligand displacement assays and docking studies on estrogen receptors α and β, glucocorticoid receptor, and progesterone receptor gave information about the specificity of the 11 most active compounds.

Zanthoxylum lemairei is widely used in African folk medicine for its pharmacological relevance. Chemical investigation of the ethanol extract from the leaves of this plant lead to the isolation of two new tetraflavonoids, lemairones A (1) and B (2), along with three known compounds, lupeol, sitosterol, and sitosterol 3-O-β-d-glucopyranoside. The antibacterial screening of the leaves of this plant, characterization of compounds 1 and 2, and their antibacterial activity are reported for the first time. The isolation of the compounds was performed using different chromatographic methods while their structures were elucidated by spectroscopic techniques including MS and NMR, and by comparison of data with those of similar flavonoids reported in the literature. The isolated compounds and the crude extract were tested against ten Gram negative multi-resistance bacterial strains including clinical isolates using a broth dilution method. The crude ethanol extract showed weak activity against the tested bacteria strains with a minimal inhibitory concentration (MIC) ranging from 512 to 1024 μg/mL. Among the isolated metabolites, only the new tetraflavonoids were tested. Lemairone A displayed weak activity while lemairone B had moderate activity against the resistant Escherichia coli AG100 with MIC values of 128 μg/mL and 64 μg/mL respectively. In addition, both molecules displayed weak activity against Klebsiella pneumoniae KP55 (MIC 128 μg/mL).

Hygrophorone B12, a new antifungal constituent from the fruiting bodies of Hygrophorus abieticola, has been isolated and subsquently synthesized in enantiomerically pure form. The total synthesis includes a Sharpless asymmetric dihydroxylation protocol as the stereodifferentiating step, followed by two diastereoselective aldol‐type reactions. The approach allows the unambiguous control of all three stereogenic centres, and, furthermore, unequivocal determination of the relative and absolute configuration of antibiotic hygrophorones B for the first time.