Geschmack ist vorhersagbar: Mit FlavorMiner. FlavorMiner heißt das Tool, das IPB-Chemiker und Partner aus Kolumbien jüngst entwickelt haben. Das Programm kann, basierend auf maschinellem Lernen (KI), anhand der…
Seit Februar 2021 bietet Wolfgang Brandt, ehemaliger Leiter der Arbeitsgruppe Computerchemie am IPB, sein Citizen Science-Projekt zur Pilzbestimmung an. Dafür hat er in regelmäßigen Abständen öffentliche Vorträge zur Vielfalt…
Plant immunity is a multilayered process that includes recognition of patterns or effectors from pathogens to elicit defense responses. These include the induction of a cocktail of defense metabolites that typically restrict pathogen virulence. Here, we investigate the interaction between barley roots and the fungal pathogens Bipolaris sorokiniana (Bs) and Fusarium graminearum (Fg) at the metabolite level. We identify hordedanes, a previously undescribed set of labdane-related diterpenoids with antimicrobial properties, as critical players in these interactions. Infection of barley roots by Bs and Fg elicits hordedane synthesis from a 600-kb gene cluster. Heterologous reconstruction of the biosynthesis pathway in yeast and Nicotiana benthamiana produced several hordedanes, including one of the most functionally decorated products 19-b-hydroxy-hordetrienoic acid (19-OH-HTA). Barley mutants in the diterpene synthase genes of this cluster are unable to produce hordedanes but, unexpectedly, show reduced Bs colonization. By contrast, colonization by Fusarium graminearum, another fungal pathogen of barley and wheat, is 4-fold higher in the mutants completely lacking hordedanes. Accordingly, 19-OH-HTA enhances both germination and growth of Bs, whereas it inhibits other pathogenic fungi, including Fg. Analysis of microscopy and transcriptomics data suggest that hordedanes delay the necrotrophic phase of Bs. Taken together, these results show that adapted pathogens such as Bs can subvert plant metabolic defenses to facilitate root colonization.
Publikation
Noleto‐Dias, C.; Farag, M. A.; Porzel, A.; Tavares, J. F.; Wessjohann, L. A.;A multiplex approach of MS, 1D‐, and 2D‐NMR metabolomics in plant ontogeny: A case study on Clusia minor L. organs (leaf, flower, fruit, and seed)Phytochem. Anal.35445-468(2024)DOI: 10.1002/pca.3300
Introduction: The genus Clusia L. is mostly recognised for the production of prenylated benzophenones and tocotrienol derivatives.Objectives: The objective of this study was to map metabolome variation within Clusia minor organs at different developmental stages.Material and Methods: In total 15 organs/stages (leaf, flower, fruit, and seed) were analysed by UPLC‐MS and 1H‐ and heteronuclear multiple‐bond correlation (HMBC)‐NMR‐based metabolomics.Results: This work led to the assignment of 46 metabolites, belonging to organic acids(1), sugars(2) phenolic acids(1), flavonoids(3) prenylated xanthones(1) benzophenones(4) and tocotrienols(2). Multivariate data analyses explained the variability and classification of samples, highlighting chemical markers that discriminate each organ/stage. Leaves were found to be rich in 5‐hydroxy‐8‐methyltocotrienol (8.5 μg/mg f.w.), while flowers were abundant in the polyprenylated benzophenone nemorosone with maximum level detected in the fully mature flower bud (43 μg/mg f.w.). Nemorosone and 5‐hydroxy tocotrienoloic acid were isolated from FL6 for full structural characterisation. This is the first report of the NMR assignments of 5‐hydroxy tocotrienoloic acid, and its maximum level was detected in the mature fruit at 50 μg/mg f.w. Seeds as typical storage organ were rich in sugars and omega‐6 fatty acids.Conclusion: To the best of our knowledge, this is the first report on a comparative 1D‐/2D‐NMR approach to assess compositional differences in ontogeny studies compared with LC‐MS exemplified by Clusia organs. Results derived from this study provide better understanding of the stages at which maximal production of natural compounds occur and elucidate in which developmental stages the enzymes responsible for the production of such metabolites are preferentially expressed.
Publikation
Noleto-Dias, C.; Picoli, E. A. T.; Porzel, A.; Wessjohann, L. A.; Tavares, J. F.; Farag, M. A.;Metabolomics characterizes early metabolic changes and markers of tolerant Eucalyptus ssp. clones against drought stressPhytochemistry212113715(2023)DOI: 10.1016/j.phytochem.2023.113715
L’Hér. (Myrtaceae) is one of the economically most important and widely cultivated trees for wood crop purposes worldwide. Climatic changes together with the constant need to expand plantations to areas that do not always provide optimal conditions for plant growth highlight the need to assess the impact of abiotic stresses on eucalypt trees. We aimed to unveil the drought effect on the leaf metabolome of commercial clones with differential phenotypic response to this stress. For this, seedlings of 13 clones were grown at well-watered (WW) and water-deficit (WD) conditions and their leaf extracts were subjected to comparative analysis using ultra-high performance liquid chromatography coupled to mass spectrometry (UPLC-MS) and nuclear magnetic resonance spectroscopy (NMR). UPLC-MS and NMR analyses led to the annotation of over 100 molecular features of classes such as cyclitols, phenolics, flavonoids, formylated phloroglucinol compounds (FPCs) and fatty acids. Multivariate data analysis was employed for specimens\' classifications and markers identification from both platforms. The results obtained in this work allowed us to classify clones differing in drought tolerance. Classification models were validated using an extra subset of samples. Tolerant plants exposed to water deficit accumulated arginine, gallic acid derivatives, caffeic acid and tannins at higher levels. In contrast, stressed drought-sensitive clones were characterised by a significant reduction in glucose, inositol and shikimic acid levels. These changes in contrasting drought response eucalypt pave ways for differential outcomes of tolerant and susceptible phenotypes. Under optimal growth conditions, all clones were rich in FPCs. These results can be used for early screening of tolerant clones and to improve our understanding of the role of these biomarkers in Eucalyptus tolerance to drought stress.
Publikation
Lam, Y. T. H.; Hoppe, J.; Dang, Q. N.; Porzel, A.; Soboleva, A.; Brandt, W.; Rennert, R.; Hussain, H.; Davari, M. D.; Wessjohann, L.; Arnold, N.;Purpurascenines A–C, azepino-indole alkaloids from Cortinarius purpurascens: Isolation, biosynthesis, and activity studies on the 5-HT2A receptorJ. Nat. Prod.861373-1384(2023)DOI: 10.1021/acs.jnatprod.2c00716
Three previously undescribed azepino-indole alkaloids, named purpurascenines A−C (1−3), together with the new-to-nature 7-hydroxytryptophan (4) as well as two known compounds, adenosine (5) and riboflavin (6), were isolated from fruiting bodies of Cortinarius purpurascens Fr. (Cortinariaceae). The structures of 1−3 were elucidated based on spectroscopic analyses and ECD calculations. Furthermore, the biosynthesis of purpurascenine A (1) was investigated by in vivo experiments using 13C-labeled sodium pyruvate, alanine, and sodium acetate incubated with fruiting bodies of C. purpurascens. The incorporation of 13C into 1 was analyzed using 1D NMR and HRESIMS methods. With [3-13C]-pyruvate, a dramatic enrichment of 13C was observed, and hence a biosynthetic route via a direct Pictet−Spengler reaction between α-keto acids and 7-hydroxytryptophan (4) is suggested for the biosynthesis of purpurascenines A−C (1−3). Compound 1 exhibits no antiproliferative or cytotoxic effects against human prostate (PC-3), colorectal (HCT-116), and breast (MCF-7) cancer cells. An in silico docking study confirmed the hypothesis that purpurascenine A (1) could bind to the 5-HT2A serotonin receptor’s active site. A new functional 5-HT2A receptor activation assay showed no functional agonistic but some antagonistic effects of 1 against the 5-HT-dependent 5-HT2A activation and likely antagonistic effects on putative constitutive activity of the 5-HT2A receptor.