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…
Jasmonates (JAs) are a family of oxylipin phytohormones regulating plant development and growth and mediating ‘defense versus growth’ responses. The upstream JA biosynthetic precursor cis-(+)-12-oxo-phytodienoic acid (cis-OPDA) acts independently of CORONATIVE INSENSITIVE 1 (COI1)-mediated JA signaling in several stress-induced and developmental processes. However, its perception and metabolism are only partially understood. A few years ago, a low abundant isoleucine analog of the biologically active JA-Ile, OPDA-Ile, was detected years ago in wounded leaves of flowering plants, opening up the possibility that conjugation of cis-OPDA to amino acids might be a relevant mechanism for cis-OPDA regulation. Here, we extended the analysis of amino acid conjugates of cis-OPDA and identified naturally occurring OPDA-Val, OPDA-Phe, OPDA-Ala, OPDA-Glu, and OPDA-Asp accumulating in response to biotic and abiotic stress in Arabidopsis (Arabidopsis thaliana). The OPDA-amino acid conjugates displayed cis-OPDA-related plant responses in a JA-Ile-dependent manner. We also showed that the synthesis and hydrolysis of cis-OPDA amino acid conjugates are mediated by members of the amidosynthetase GRETCHEN HAGEN 3 (GH3) and the amidohydrolase INDOLE-3-ACETYL-LEUCINE RESISTANT 1 (ILR1)/ILR1-like (ILL) families. Thus, OPDA amino acid conjugates function in the catabolism or temporary storage of cis-OPDA in stress responses instead of acting as chemical signals per se.
Preprints
Zheng, K.; Lyu, J. C.; Thomas, E. L.; Schuster, M.; Sanguankiattichai, N.; Ninck, S.; Kaschani, F.; Kaiser, M.; Hoorn, R. A.;The proteome of agroinfiltrated Nicotiana benthamiana is shaped by extensive protein processingbioRxiv(2024)DOI: 10.1101/2023.11.02.565301
Processing by proteases irreversibly regulates the fate of plant proteins and hampers the production of recombinant protein in plants, yet only few processing events have been described in agroinfiltrated Nicotiana benthamiana, which has emerged as a favorite transient protein expression platform in plant science and molecular pharming. Here, we used in-gel digests and mass spectrometry to monitor the migration and topography of 5,040 plant proteins of agroinfiltrated N. benthamiana within a protein gel. By plotting the peptides over the gel slices, we generated peptographs that reveal where which part of each protein was detected within the protein gel. These data uncovered that 60% of the detected proteins have proteoforms that migrate at lower than predicted molecular weights, implicating extensive proteolytic processing. For instance, this analysis confirms the proteolytic removal and degradation of autoinhibitory prodomains of most but not all proteases, and revealed differential processing within pectinemethylesterase and lipase families. This analysis also uncovered intricate processing of glycosidases and uncovered that ectodomain shedding might be common for a diverse range of receptor-like kinases. Transient expression of double-tagged candidate proteins confirmed various processing events in vivo. This extensive proteomic dataset can be investigated further and demonstrates that most plant proteins are proteolytically processed and implicates an extensive proteolytic machinery shaping the proteome of agroinfiltrated N. benthamiana.
Preprints
Liu, Q.; Neefjes, A. C. M.; Kobylinska, R.; Mugford, S. T.; Marzo, M.; Canham, J.; Schuster, M.; Hoorn, R. A.; Chen, Y.; Hogenhout, S. A.;Aphid effectors suppress plant immunity via recruiting defence proteins to processing bodiesbioRxiv(2024)DOI: 10.1101/2024.11.20.624400
Aphids are small insects that have developed specialized mouthparts and effector proteins to establish long-term relationships with plants. The peach-potato aphid, Myzus persicae, is a generalist, feeding on many plant species and capable of transmitting numerous pathogens. This study reveals how host-responsive cathepsins B (CathB) in the oral secretions of M. persicae facilitate aphid survival by modulating plant immune responses. Aphid CathB localize to processing bodies (p-bodies) and recruit key immune regulators EDS1, PAD4, and ADR1 to these bodies, suppressing plant defenses. A plant protein, Acd28.9 (Hsp20 family), counteracts this CathB activity and contributes to plant resistance to aphids. These findings highlight a novel role for p-bodies in plant immunity and uncover a plant resistance mechanism to aphid infestation.
Preprints
Kourelis, J.; Schuster, M.; Demir, F.; Mattinson, O.; Krauter, S.; Kahlon, P. S.; O’Grady, R.; Royston, S.; Bravo-Cazar, A. L.; Mooney, B. C.; Huesgen, P. F.; Kamoun, S.; Hoorn, R. A.;Bioengineering secreted proteases converts divergent Rcr3 orthologs and paralogs into extracellular immune co-receptorsbioRxiv(2024)DOI: 10.1101/2024.02.14.580413
Secreted immune proteases Rcr3 and Pip1 of tomato are both inhibited by Avr2 from the fungal plant pathogen Cladosporium fulvumbut only Rcr3 act as a decoy co-receptor that detects Avr2 in the presence of the Cf-2 immune receptor. Here, we identified crucial residues from tomato Rcr3 required for Cf-2-mediated signalling and bioengineered various proteases to trigger Avr2/Cf-2 dependent immunity. Despite substantial divergences in Rcr3 orthologs from eggplant and tobacco, only minimal alterations were sufficient to trigger Avr2/Cf-2-triggered immune signalling. Tomato Pip1, by contrast, was bioengineered with 16 Rcr3-specific residues to initiate Avr2/Cf-2-triggered immune signalling. These residues cluster on one side next to the substrate binding groove, indicating a potential Cf-2 interaction site. Our findings also revealed that Rcr3 and Pip1 have distinct substrate preferences determined by two variant residues and that both are suboptimal for binding Avr2. This study advances our understanding of Avr2 perception and opens avenues to bioengineer proteases to broaden pathogen recognition in other crops.