IPB Halle: Leibniz-Institut für Pflanzenbiochemie Deutsch

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4. Juli 2025 am IPB
IPB-Newsletter | April 2025
Wir verstehen Pflanzen!

Der Film zum Institut
Molekulare Signalverarbeitung

Prof. Dr. Steffen Abel
Wie Pflanzen ihrer Umwelt trotzen.
Natur- und Wirkstoffchemie

Prof. Dr. Ludger Wessjohann
Die Chemie der Natur – Basis für Wirkstoffe zur Gesunderhaltung von Mensch und Pflanze.
Biochemie pflanzlicher Interaktionen

Prof. Dr. Tina Romeis
Wechselwirkungen in, von und mit Pflanzen.
Stoffwechsel- und Zellbiologie

Prof. Dr. Alain Tissier
Sekundär jedoch nicht zweitrangig - Die biologischen Funktionen pflanzlicher Sekundärmetaboliten.
Unabhängige Nachwuchsgruppe

Dr. Mariana Schuster

Aktuelles

Unser 10. Leibniz Plant Biochemistry Symposium am 7. und 8. Mai war ein großer Erfolg. Thematisch ging es in diesem Jahr um neue Methoden und Forschungsansätze der Naturstoffchemie. Die exzellenten Vorträge über Wirkstoffe…

Omanische Heilpflanze im Fokus der Phytochemie
IPB-Wissenschaftler und Partner aus Dhofar haben jüngst die omanische Heilpflanze Terminalia dhofarica unter die phytochemische Lupe genommen. Die Pflanze ist reich an…

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…

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Datum: 14.05.2025 Referenznummer: 10/2025

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Ortmann, S.; Marx, J.; Lampe, C.; Handrick, V.; Ehnert, T.-M.; Zinecker, S.; Reimers, M.; Bonas, U.; Lee Erickson, J.; A conserved microtubule-binding region in Xanthomonas XopL is indispensable for induced plant cell death reactions PLOS Pathog. 19 e1011263 (2023) DOI: 10.1371/journal.ppat.1011263

Pathogenic Xanthomonas bacteria cause disease on more than 400 plant species. These Gram-negative bacteria utilize the type III secretion system to inject type III effector proteins (T3Es) directly into the plant cell cytosol where they can manipulate plant pathways to promote virulence. The host range of a given Xanthomonas species is limited, and T3E repertoires are specialized during interactions with specific plant species. Some effectors, however, are retained across most strains, such as Xanthomonas Outer Protein L (XopL). As an ‘ancestral’ effector, XopL contributes to the virulence of multiple xanthomonads, infecting diverse plant species. XopL homologs harbor a combination of a leucine-rich-repeat (LRR) domain and an XL-box which has E3 ligase activity. Despite similar domain structure there is evidence to suggest that XopL function has diverged, exemplified by the finding that XopLs expressed in plants often display bacterial species-dependent differences in their sub-cellular localization and plant cell death reactions. We found that XopL from X. euvesicatoria (XopLXe) directly associates with plant microtubules (MTs) and causes strong cell death in agroinfection assays in N. benthamiana. Localization of XopLXe homologs from three additional Xanthomonas species, of diverse infection strategy and plant host, revealed that the distantly related X. campestris pv. campestris harbors a XopL (XopLXcc) that fails to localize to MTs and to cause plant cell death. Comparative sequence analyses of MT-binding XopLs and XopLXcc identified a proline-rich-region (PRR)/α-helical region important for MT localization. Functional analyses of XopLXe truncations and amino acid exchanges within the PRR suggest that MT-localized XopL activity is required for plant cell death reactions. This study exemplifies how the study of a T3E within the context of a genus rather than a single species can shed light on how effector localization is linked to biochemical activity.

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Moura, P. H. B.; Porzel, A.; Nunes, R. M.; Baratto, L. C.; Wessjohann, L. A.; Martins, R. C. C.; Leal, I. C. R.; Antioxidant capacity and fragmentation features of C‐glycoside isoflavones by high‐resolution electrospray ionization tandem mass spectrometry using collision‐induced and high‐energy collisional dissociation techniques J. Mass Spectrom. 56 e4793 (2021) DOI: 10.1002/jms.4793

The rapid annotation and identification by mass spectrometry techniques of flavonoids remains a challenge, due to their structural diversity and the limited availability of reference standards. This study applies a workflow to characterize two isoflavonoids, the orobol-C-glycosides analogs, using high-energy collisional dissociation (HCD)- and collision-induced dissociation (CID)-type fragmentation patterns, and also to evaluate the antioxidant effects of these compounds by ferric reducing antioxidant power (FRAP), 2,2′-azino-bis(3-ethylbenzothiazolin acid) 6-sulfonic acid (ABTS), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) methods. By the CID-type fragmentation, in positive mode and at all high-resolution mass spectrometry (HRMS) multiple stage, there were shown differences in the annotation of the compounds, mainly concerning some ratios of relative abundance. At CID-MS2 20 eV, the compounds could be efficiently characterized, because they present distinct base peaks [M + H]+ and [M + H–H2O]+ for the orobol-8-C- and orobol-6-C-glycoside, respectively. Similarly, by the HCD-type fragmentation, in HRMS2 stage, differences between orobol analogs in both mode of ionization were observed. However, the HR HCD-MS2 at 80 eV, in positive mode, generated more ions and each isomer presented different base peaks ions, [0,2X]+ for the orobol-8-C-glycoside and [0,3X]+ for the orobol-6-C-glycoside. By the DPPH, the 8-C-derivative showed a very close value compared with the standard rutin and, in the ABTS method, a higher radical-scavenging activity. In both methods, the EC50 of orobol-8-C-glycoside was almost twice better compared with orobol-6-C-glycoside. In FRAP, both C-glycosides showed a good capacity as Fe+3 reducing agents. We could realize that combined MS techniques, highlighting the positive mode of ionization, can be used to evaluate the isoflavones analogs being useful to differentiate between the isomeric flavones; therefore, these data are important to mass spectrometry dereplication studies become more efficient.

Publikation

Schmidt, J.; Kuck, D.; Franke, K.; Sultani, H.; Laub, A.; Wessjohann, L. A.; The unusual fragmentation of long-chain feruloyl esters under negative ion electrospray conditions J. Mass Spectrom. 54 549-556 (2019) DOI: 10.1002/jms.4357

Publikation

Ruttkies, C.; Schymanski, E. L.; Strehmel, N.; Hollender, J.; Neumann, S.; Williams, A. J.; Krauss, M.; Supporting non-target identification by adding hydrogen deuterium exchange MS/MS capabilities to MetFrag Anal. Bioanal. Chem. 411 4683-4700 (2019) DOI: 10.1007/s00216-019-01885-0

Liquid chromatography coupled with high-resolution mass spectrometry (LC-HRMS) is increasingly popular for the non-targeted exploration of complex samples, where tandem mass spectrometry (MS/MS) is used to characterize the structure of unknown compounds. However, mass spectra do not always contain sufficient information to unequivocally identify the correct structure. This study investigated how much additional information can be gained using hydrogen deuterium exchange (HDX) experiments. The exchange of “easily exchangeable” hydrogen atoms (connected to heteroatoms), with predominantly [M+D]+ ions in positive mode and [M-D]− in negative mode was observed. To enable high-throughput processing, new scoring terms were incorporated into the in silico fragmenter MetFrag. These were initially developed on small datasets and then tested on 762 compounds of environmental interest. Pairs of spectra (normal and deuterated) were found for 593 of these substances (506 positive mode, 155 negative mode spectra). The new scoring terms resulted in 29 additional correct identifications (78 vs 49) for positive mode and an increase in top 10 rankings from 80 to 106 in negative mode. Compounds with dual functionality (polar head group, long apolar tail) exhibited dramatic retention time (RT) shifts of up to several minutes, compared with an average 0.04 min RT shift. For a smaller dataset of 80 metabolites, top 10 rankings improved from 13 to 24 (positive mode, 57 spectra) and from 14 to 31 (negative mode, 63 spectra) when including HDX information. The results of standard measurements were confirmed using targets and tentatively identified surfactant species in an environmental sample collected from the river Danube near Novi Sad (Serbia). The changes to MetFrag have been integrated into the command line version available at http://c-ruttkies.github.io/MetFrag and all resulting spectra and compounds are available in online resources and in the Electronic Supplementary Material (ESM).

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Lange Nacht, die Wissen schafft

IPB-Newsletter | April 2025

Wir verstehen Pflanzen!

Molekulare Signalverarbeitung

Natur- und Wirkstoffchemie

Biochemie pflanzlicher Interaktionen

Stoffwechsel- und Zellbiologie

Unabhängige Nachwuchsgruppe

Aktuelles

Gelungenes Symposium

+++ Newsticker Wissenschaft #182 +++ Naturstoffe +++

+++ Newsticker Wissenschaft #181 +++ Maschinelles Lernen +++

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Referent*in der Geschäftsführung (m/w/d) (10/2025)

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