Publications by authors named "Ivo Feussner"

243 Publications

Chemokine-like MDL proteins modulate flowering time and innate immunity in plants.

J Biol Chem 2021 Mar 30:100611. Epub 2021 Mar 30.

RWTH Aachen University, Institute of Biology I, Unit of Plant Molecular Cell Biology, 52056, Aachen, Germany. Electronic address:

Human macrophage migration inhibitory factor (MIF) is an atypical chemokine implicated in intercellular signaling and innate immunity. MIF orthologs (MIF/D-DT-like proteins, MDLs) are present throughout the plant kingdom, but remain experimentally unexplored in these organisms. Here, we provide an in planta characterization and functional analysis of the three-member gene/protein MDL family in Arabidopsis thaliana. Subcellular localization experiments indicated a nucleo-cytoplasmic distribution of MDL1 and MDL2, while MDL3 is localized to peroxisomes. Protein-protein interaction assays revealed the in vivo formation of MDL1, MDL2, and MDL3 homo-oligomers, as well as the formation of MDL1-MDL2 hetero-oligomers. Functionally, Arabidopsis mdl mutants exhibited a delayed transition from vegetative to reproductive growth (flowering) under long-day conditions, but not in a short-day environment. In addition, mdl mutants were more resistant to colonization by the bacterial pathogen Pseudomonas syringae pv. maculicola. The latter phenotype was compromised by the additional mutation of SALICYLIC ACID INDUCTION DEFICIENT 2 (SID2), a gene, implicated in the defense-induced biosynthesis of the key signaling molecule salicylic acid; however, the enhanced antibacterial immunity was not associated with any constitutive or pathogen-induced alterations in the levels of characteristic phytohormones or defense-associated metabolites. Interestingly, bacterial infection triggered relocalization and accumulation of MDL1 and MDL2 at the peripheral lobes of leaf epidermal cells. Collectively, our data indicate redundant functionality and a complex interplay between the three chemokine-like Arabidopsis MDL proteins in the regulation of both developmental and immune-related processes. These insights expand the comparative cross-kingdom analysis of MIF/MDL signaling in human and plant systems.
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http://dx.doi.org/10.1016/j.jbc.2021.100611DOI Listing
March 2021

Sphingolipid long-chain base hydroxylation influences plant growth and callose deposition in Physcomitrium patens.

New Phytol 2021 Mar 15. Epub 2021 Mar 15.

University of Goettingen, Albrecht-von-Haller-Institute for Plant Sciences, Department of Plant Biochemistry, D-37077, Goettingen, Germany.

Sphingolipids are enriched in microdomains in the plant plasma membrane (PM). Hydroxyl groups in the characteristic long-chain base (LCB) moiety might be essential for the interaction between sphingolipids and sterols during microdomain formation. Investigating LCB hydroxylase mutants in Physcomitrium patens might therefore reveal the role of certain plant sphingolipids in the formation of PM subdomains. Physcomitrium patens mutants for the LCB C-4 hydroxylase S4H were generated by homologous recombination. Plants were characterised by analysing their sphingolipid and glycosylated sterol (SG) profiles and by investigating different gametophyte stages. s4h mutants lost the hydroxyl group at the C-4 position of their LCB moiety. Loss of this hydroxyl group caused global changes in the moss sphingolipidome and in SG composition. Changes in membrane lipid composition may trigger growth defects by interfering with the localisation of membrane-associated proteins that are crucial for growth processes such as signalling receptors or callose-modifying enzymes. Loss of LCB-C4 hydroxylation substantially changes the P. patens sphingolipidome and reveals a key role for S4H during development of non-vascular plants. P. patens represents a valuable model for studying the diversification of plant sphingolipids. The simple anatomy of P. patens facilitates visualisation of physiological processes in biological membranes.
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http://dx.doi.org/10.1111/nph.17345DOI Listing
March 2021

Mitochondrial Small Heat Shock Proteins Are Essential for Normal Growth of .

Front Plant Sci 2021 10;12:600426. Epub 2021 Feb 10.

Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET-UNR), Rosario, Argentina.

Mitochondria play important roles in the plant stress responses and the detoxification of the reactive oxygen species generated in the electron transport chain. Expression of genes encoding stress-related proteins such as the mitochondrial small heat shock proteins (M-sHSP) is upregulated in response to different abiotic stresses. In , three paralogous genes were identified, although their function under physiological conditions remains elusive. The aim of this work is to uncover the function of all three at the whole plant level. To accomplish this goal, we analyzed the phenotype, proteomic, and metabolic profiles of Arabidopsis knock-down lines of (single, double, and triple knock-down lines) during normal plant growth. The triple knock-down plants showed the most prominent altered phenotype at vegetative and reproductive stages without any externally applied stress. They displayed chlorotic leaves, growth arrest, and low seed production. Concomitantly, they exhibited increased levels of sugars, proline, and citric, malic, and ascorbic acid, among other metabolites. In contrast, single and double knock-down plants displayed a few changes in their phenotype. A redundant function among the three M-sHSPs is indicated by the impairment in vegetative and reproductive growth associated with the simultaneous loss of all three genes. The triple knock-down lines showed alteration of proteins mainly involved in photosynthesis and antioxidant defense compared to the control plants. On the other hand, heat stress triggered a distinct cytosolic response pattern and the upregulation of other sHSP members, in the knock-down plants. Overall, depletion of all three M-sHSPs in Arabidopsis severely impacted fundamental metabolic processes, leading to alterations in the correct plant growth and development. These findings expand our knowledge about the contribution of organelle-specific M-sHSPs to healthy plant growth under non-stress conditions.
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http://dx.doi.org/10.3389/fpls.2021.600426DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7902927PMC
February 2021

Fatty Acids and their Derivatives as Renewable Platform Molecules for the Chemical Industry.

Angew Chem Int Ed Engl 2021 Feb 22. Epub 2021 Feb 22.

Carl von Ossietzky Universität Oldenburg: Carl von Ossietzky Universitat Oldenburg, Institute of Chemistry, GERMANY.

Oils and fats of vegetable and animal origin remain an important renewable feedstock for the chemical industry. Their industrial use has increased during the last 10 years from 31 to 51 million tonnes. Remarkable achievements made in the field of oleochemistry in this timeframe are summarized herein, including the reduction of fatty esters to ethers, the selective oxidation and oxidative cleavage of double bonds, the synthesis of alkyl branched fatty compounds, the isomerizing hydroformylation and alkoxycarboxylation, and olefin metathesis. The use of oleochemicals for the synthesis of a great variety of polymeric materials has increased tremendously, too. In addition to lipases or phospholipases, other enzymes found their way into biocatalytic oleochemistry. Important achievements also generated new oil qualities in existing crop plants or by using microorganisms optimized by metabolic engineering.
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http://dx.doi.org/10.1002/anie.202100778DOI Listing
February 2021

The glycosyltransferase UGT76B1 modulates N-hydroxy-pipecolic acid homeostasis and plant immunity.

Plant Cell 2021 Jan 11. Epub 2021 Jan 11.

Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, University of Goettingen, D-37077 Goettingen, Germany.

The tradeoff between growth and defense is a critical aspect of plant immunity. Therefore, the plant immune response needs to be tightly regulated. Salicylic acid (SA) is an important plant hormone regulating defense against biotrophic pathogens. Recently, N-hydroxy-pipecolic acid (NHP) was identified as another regulator for plant innate immunity and systemic acquired resistance (SAR). Although the biosynthetic pathway leading to NHP formation is already been identified, how NHP is further metabolized is unclear. Here, we present UGT76B1 as a uridine diphosphate-dependent glycosyltransferase (UGT) that modifies NHP by catalyzing the formation of 1-O-glucosyl-pipecolic acid in Arabidopsis thaliana. Analysis of T-DNA and clustered regularly interspaced short palindromic repeats (CRISPR) knock-out mutant lines of UGT76B1 by targeted and nontargeted ultra-high performance liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-HRMS) underlined NHP and SA as endogenous substrates of this enzyme in response to Pseudomonas infection and UV treatment. ugt76b1 mutant plants have a dwarf phenotype and constitutive defense response which can be suppressed by loss of function of the NHP biosynthetic enzyme FLAVIN-DEPENDENT MONOOXYGENASE 1 (FMO1). This suggests that elevated accumulation of NHP contributes to the enhanced disease resistance in ugt76b1. Externally applied NHP can move to distal tissue in ugt76b1 mutant plants. Although glycosylation is not required for the long-distance movement of NHP during SAR, it is crucial to balance growth and defense.
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http://dx.doi.org/10.1093/plcell/koaa045DOI Listing
January 2021

Jasmonic acid biosynthesis by fungi: derivatives, first evidence on biochemical pathways and culture conditions for production.

PeerJ 2021 5;9:e10873. Epub 2021 Feb 5.

Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, University of Goettingen, Goettingen, Germany.

Jasmonic acid (JA) and its derivatives called jasmonates (JAs) are lipid-derived signalling molecules that are produced by plants and certain fungi. Beside this function, JAs have a great variety of applications in flavours and fragrances production. In addition, they may have a high potential in agriculture. JAs protect plants against infections. Although there is much information on the biosynthesis and function of JA concerning plants, knowledge on these aspects is still scarce for fungi. Taking into account the practical importance of JAs, the objective of this review is to summarize knowledge on the occurrence of JAs from fungal culture media, their biosynthetic pathways and the culture conditions for optimal JA production as an alternative source for the production of these valuable metabolites.
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http://dx.doi.org/10.7717/peerj.10873DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7869668PMC
February 2021

Convergence of sphingolipid desaturation across over 500 million years of plant evolution.

Nat Plants 2021 02 25;7(2):219-232. Epub 2021 Jan 25.

Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, University of Goettingen, Goettingen, Germany.

For plants, acclimation to low temperatures is fundamental to survival. This process involves the modification of lipids to maintain membrane fluidity. We previously identified a new cold-induced putative desaturase in Physcomitrium (Physcomitrella) patens. Lipid profiles of null mutants of this gene lack sphingolipids containing monounsaturated C24 fatty acids, classifying the new protein as sphingolipid fatty acid denaturase (PpSFD). PpSFD mutants showed a cold-sensitive phenotype as well as higher susceptibility to the oomycete Pythium, assigning functions in stress tolerance for PpSFD. Ectopic expression of PpSFD in the Atads2.1 (acyl coenzyme A desaturase-like 2) Arabidopsis thaliana mutant functionally complemented its cold-sensitive phenotype. While these two enzymes catalyse a similar reaction, their evolutionary origin is clearly different since AtADS2 is a methyl-end desaturase whereas PpSFD is a cytochrome b fusion desaturase. Altogether, we suggest that adjustment of membrane fluidity evolved independently in mosses and seed plants, which diverged more than 500 million years ago.
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http://dx.doi.org/10.1038/s41477-020-00844-3DOI Listing
February 2021

ABA-Dependent Salt Stress Tolerance Attenuates Immunity in Arabidopsis.

Front Plant Sci 2020 17;11:594827. Epub 2020 Nov 17.

Department of Plant Biochemistry, Center for Plant Molecular Biology, Eberhard Karls University of Tübingen, Tübingen, Germany.

Plants have evolved adaptive measures to cope with abiotic and biotic challenges simultaneously. Combinatorial stress responses require environmental signal integration and response prioritization to balance stress adaptation and growth. We have investigated the impact of salt, an important environmental factor in arid regions, on the innate immune response. Activation of a classical salt stress response resulted in increased susceptibility to infection with hemibiotrophic or necrotrophic , and , respectively. Surprisingly, pattern-triggered immunity (PTI)-associated responses were largely unaffected upon salt pre-treatment. However, we further observed a strong increase in phytohormone levels. Particularly, abscisic acid (ABA) levels were already elevated before pathogen infection, and application of exogenous ABA substituted for salt-watering in increasing susceptibility toward infection. We propose a regulatory role of ABA in attenuating immunity in this plant under salt stress conditions.
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http://dx.doi.org/10.3389/fpls.2020.594827DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7704454PMC
November 2020

Ustilago maydis effector Jsi1 interacts with Topless corepressor, hijacking plant jasmonate/ethylene signaling.

New Phytol 2021 03 3;229(6):3393-3407. Epub 2021 Jan 3.

Gregor Mendel Institute of Molecular Plant Biology (GMI), Austrian Academy of Sciences (OEAW), Vienna BioCenter (VBC), Vienna, 1030, Austria.

Ustilago maydis is the causal agent of maize smut disease. During the colonization process, the fungus secretes effector proteins that suppress immune responses and redirect the host metabolism in favor of the pathogen. As effectors play a critical role during plant colonization, their identification and functional characterization are essential to understanding biotrophy and disease. Using biochemical, molecular, and transcriptomic techniques, we performed a functional characterization of the U. maydis effector Jasmonate/Ethylene signaling inducer 1 (Jsi1). Jsi1 interacts with several members of the plant corepressor family Topless/Topless related (TPL/TPR). Jsi1 expression in Zea mays and Arabidopsis thaliana leads to transcriptional induction of the ethylene response factor (ERF) branch of the jasmonate/ethylene (JA/ET) signaling pathway. In A. thaliana, activation of the ERF branch leads to biotrophic susceptibility. Jsi1 likely activates the ERF branch via an EAR (ET-responsive element binding-factor-associated amphiphilic repression) motif, which resembles EAR motifs from plant ERF transcription factors, that interacts with TPL/TPR proteins. EAR-motif-containing effector candidates were identified from different fungal species, including Magnaporthe oryzae, Sporisorium scitamineum, and Sporisorium reilianum. Interaction between plant TPL proteins and these effector candidates from biotrophic and hemibiotrophic fungi indicates the convergent evolution of effectors modulating the TPL/TPR corepressor hub.
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http://dx.doi.org/10.1111/nph.17116DOI Listing
March 2021

Quantitative Hormone Signaling Output Analyses of Interactions With Virulent and Avirulent Isolates at Single-Cell Resolution.

Front Plant Sci 2020 6;11:603693. Epub 2020 Nov 6.

Department of Plant Cell Biology, Albrecht-von-Haller Institute of Plant Sciences, University of Göttingen, Göttingen, Germany.

The phytohormones salicylic acid (SA), jasmonic acid (JA), and ethylene (ET) are central regulators of biotic and abiotic stress responses in . Here, we generated modular fluorescent protein-based reporter lines termed COLORFUL-PR1pro, -VSP2pro, and -PDF1.2apro. These feature hormone-controlled nucleus-targeted transcriptional output sensors and the simultaneous constitutive expression of spectrally separated nuclear reference and plasma membrane-localized reporters. This set-up allowed the study of cell-type specific hormone activities, cellular viability and microbial invasion. Moreover, we developed a software-supported high-throughput confocal microscopy imaging protocol for output quantification to resolve the spatio-temporal dynamics of respective hormonal signaling activities at single-cell resolution. Proof-of-principle analyses in leaves revealed distinguished hormone sensitivities in mesophyll, epidermal pavement and stomatal guard cells, suggesting cell type-specific regulatory protein activities. In plant-microbe interaction studies, we found that virulent and avirulent () isolates exhibit different invasion dynamics and induce spatio-temporally distinct hormonal activity signatures. On the cellular level, these hormone-controlled reporter signatures demarcate the nascent sites of entry and progression, and highlight initiation, transduction and local containment of immune signals.
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http://dx.doi.org/10.3389/fpls.2020.603693DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7677359PMC
November 2020

Update on LIPID MAPS classification, nomenclature, and shorthand notation for MS-derived lipid structures.

J Lipid Res 2020 12 9;61(12):1539-1555. Epub 2020 Oct 9.

Department of Molecular Biosciences, University of Graz, Graz, Austria; Division of Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria. Electronic address:

A comprehensive and standardized system to report lipid structures analyzed by MS is essential for the communication and storage of lipidomics data. Herein, an update on both the LIPID MAPS classification system and shorthand notation of lipid structures is presented for lipid categories Fatty Acyls (FA), Glycerolipids (GL), Glycerophospholipids (GP), Sphingolipids (SP), and Sterols (ST). With its major changes, i.e., annotation of ring double bond equivalents and number of oxygens, the updated shorthand notation facilitates reporting of newly delineated oxygenated lipid species as well. For standardized reporting in lipidomics, the hierarchical architecture of shorthand notation reflects the diverse structural resolution powers provided by mass spectrometric assays. Moreover, shorthand notation is expanded beyond mammalian phyla to lipids from plant and yeast phyla. Finally, annotation of atoms is included for the use of stable isotope-labeled compounds in metabolic labeling experiments or as internal standards. This update on lipid classification, nomenclature, and shorthand annotation for lipid mass spectra is considered a standard for lipid data presentation.
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http://dx.doi.org/10.1194/jlr.S120001025DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7707175PMC
December 2020

Acyltransferases Regulate Oil Quality in Through Both Acyl Donor and Acyl Acceptor Specificities.

Front Plant Sci 2020 14;11:1144. Epub 2020 Aug 14.

Department of Plant Breeding, Swedish University of Agricultural Sciences, Alnarp, Sweden.

is an emerging biotechnology oil crop. However, more information is needed regarding its innate lipid enzyme specificities. We have therefore characterized several triacylglycerol (TAG) producing enzymes by measuring substrate specificities using different combinations of acyl-acceptors (diacylglycerol, DAG) and donors. Specifically, acyl-CoA:diacylglycerol acyltransferase (DGAT) 1 and 2 (which both use acyl-CoA as acyl donor) and phospholipid:diacylglycerol acyltransferase (PDAT, with phosphatidylcoline as acyl donor) were studied. The results show that the DGAT1 and DGAT2 specificities are complementary, with DGAT2 exhibiting a high specificity for acyl acceptors containing only polyunsaturated fatty acids (FAs), whereas DGAT1 prefers acyl donors with saturated and monounsaturated FAs. Furthermore, the combination of substrates that resulted in the highest activity for DGAT2, but very low activity for DGAT1, corresponds to TAG species previously shown to increase in seeds with downregulated DGAT1. Similarly, the combinations of substrates that gave the highest PDAT1 activity were also those that produce the two TAG species (54:7 and 54:8 TAG) with the highest increase in PDAT overexpressing seeds. Thus, the data correlate well with the changes in the overall fatty acid profile and TAG species in seeds with altered DGAT1 and PDAT activity. Additionally, studies of phosphatidycholine:diacylglycerol cholinephosphotransferase (PDCT), another activity involved in TAG biosynthesis, revealed that PDCT accepts substrates with different desaturation levels. Furthermore, PDCT was unable to use DAG with ricineoleyl groups, and the presence of this substrate also inhibited PDCT from using other DAG-moieties. This gives insights relating to previous studies regarding this enzyme.
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http://dx.doi.org/10.3389/fpls.2020.01144DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7456936PMC
August 2020

Elicits Media-Dependent Secretome Responses With Capacity to Distinguish Between Plant-Related Environments.

Front Microbiol 2020 6;11:1876. Epub 2020 Aug 6.

Department of Molecular Microbiology and Genetics, Göttingen Center for Molecular Biosciences, Institute of Microbiology and Genetics, University of Göttingen, Göttingen, Germany.

Verticillia cause a vascular wilt disease affecting a broad range of economically valuable crops. The fungus enters its host plants through the roots and colonizes the vascular system. It requires extracellular proteins for a successful plant colonization. The exoproteomes of the allodiploid upon cultivation in different media or xylem sap extracted from its host plant were compared. Secreted fungal proteins were identified by label free liquid chromatography-tandem mass spectrometry screening. induced two main secretion patterns. One response pattern was elicited in various non-plant related environments. The second pattern includes the exoprotein responses to the plant-related media, pectin-rich simulated xylem medium and pure xylem sap, which exhibited similar but additional distinct features. These exoproteomes include a shared core set of 221 secreted and similarly enriched fungal proteins. The pectin-rich medium significantly induced the secretion of 143 proteins including a number of pectin degrading enzymes, whereas xylem sap triggered a smaller but unique fungal exoproteome pattern with 32 enriched proteins. The latter pattern included proteins with domains of known pathogenicity factors, metallopeptidases and carbohydrate-active enzymes. The most abundant proteins of these different groups are the necrosis and ethylene inducing-like proteins Nlp2 and Nlp3, the cerato-platanin proteins Cp1 and Cp2, the metallopeptidases Mep1 and Mep2 and the carbohydrate-active enzymes Gla1, Amy1 and Cbd1. Their pathogenicity contribution was analyzed in the haploid parental strain . Deletion of the majority of the corresponding genes caused no phenotypic changes during growth or invasion and colonization of tomato plants. However, we discovered that the , , and deletion strains were compromised in plant infections. Overall, our exoproteome approach revealed that the fungus induces specific secretion responses in different environments. The fungus has a general response to non-plant related media whereas it is able to fine-tune its exoproteome in the presence of plant material. Importantly, the xylem sap-specific exoproteome pinpointed Nlp2 and Nlp3 as single effectors required for successful colonization.
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http://dx.doi.org/10.3389/fmicb.2020.01876DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7423881PMC
August 2020

Ectomycorrhizal fungi induce systemic resistance against insects on a nonmycorrhizal plant in a CERK1-dependent manner.

New Phytol 2020 10 8;228(2):728-740. Epub 2020 Jul 8.

Michael Smith Laboratories, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.

Below-ground microbes can induce systemic resistance against foliar pests and pathogens on diverse plant hosts. The prevalence of induced systemic resistance (ISR) among plant-microbe-pest systems raises the question of host specificity in microbial induction of ISR. To test whether ISR is limited by plant host range we tested the ISR-inducing ectomycorrhizal fungus Laccaria bicolor on the nonmycorrhizal plant Arabidopsis thaliana. We used the cabbage looper Trichoplusia ni and bacterial pathogen Pseudomonas syringae pv. tomato DC3000 (Pto) as readouts for ISR on Arabidopsis. We found that root inoculation with L. bicolor triggered ISR against T. ni and induced systemic susceptibility (ISS) against the bacterial pathogen Pto. We found that L. bicolor-triggered ISR against T. ni was dependent on jasmonic acid signaling and salicylic acid biosynthesis and signaling. Heat-killed L. bicolor and chitin were sufficient to trigger ISR against T. ni and ISS against Pto. The chitin receptor CERK1 was necessary for L. bicolor-mediated effects on systemic immunity. Collectively our findings suggest that some ISR responses might not require intimate symbiotic association, but rather might be the result of root perception of conserved microbial signals.
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http://dx.doi.org/10.1111/nph.16715DOI Listing
October 2020

The Fifth WS/DGAT Enzyme of the Bacterium Marinobacter aquaeolei VT8.

Lipids 2020 09 20;55(5):479-494. Epub 2020 May 20.

Department for Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, University of Goettingen, 37077, Goettingen, Germany.

Wax esters (WE) belong to the class of neutral lipids. They are formed by an esterification of a fatty alcohol and an activated fatty acid. Dependent on the chain length and desaturation degree of the fatty acid and the fatty alcohol moiety, WE can have diverse physicochemical properties. WE derived from monounsaturated long-chain acyl moieties are of industrial interest due to their very good lubrication properties. Whereas WE were obtained in the past from spermaceti organs of the sperm whale, industrial WE are nowadays mostly produced chemically from fossil fuels. In order to produce WE more sustainably, attempts to produce industrial WE in transgenic plants are steadily increasing. To achieve this, different combinations of WE producing enzymes are expressed in developing Arabidopsis thaliana or Camelina sativa seeds. Here we report the identification and characterization of a fifth wax synthase from the organism Marinobacter aquaeolei VT8, MaWSD5. It belongs to the class of bifunctional wax synthase/acyl-CoA:diacylglycerol O-acyltransferases (WSD). The protein was purified to homogeneity. In vivo and in vitro substrate analyses revealed that MaWSD5 is able to synthesize WE but no triacylglycerols. The protein produces WE from saturated and monounsaturated mid- and long-chain substrates. Arabidopsis thaliana seeds expressing a fatty acid reductase from Marinobacter aquaeolei VT8 and MaWSD5 produce WE. Main WE synthesized are 20:1/18:1 and 20:1/20:1. This makes MaWSD5 a suitable candidate for industrial WE production in planta.
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http://dx.doi.org/10.1002/lipd.12250DOI Listing
September 2020

Ex Vivo Metabolomics: A Powerful Approach for Functional Gene Annotation.

Trends Plant Sci 2020 08 25;25(8):829-830. Epub 2020 Apr 25.

Department for Plant Biochemistry, Albrecht von Haller Institute for Plant Sciences, University of Goettingen, Goettingen, Germany; Service Unit for Metabolomics and Lipidomics, Goettingen Center for Molecular Biosciences (GZMB), University of Goettingen, Goettingen, Germany.

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http://dx.doi.org/10.1016/j.tplants.2020.03.012DOI Listing
August 2020

Wax biosynthesis in response to danger: its regulation upon abiotic and biotic stress.

New Phytol 2020 08 3;227(3):698-713. Epub 2020 May 3.

Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, University of Goettingen, D-37077, Goettingen, Germany.

The plant cuticle is the first physical barrier between land plants and their terrestrial environment. It consists of the polyester scaffold cutin embedded and sealed with organic, solvent-extractable cuticular waxes. Cuticular wax ultrastructure and chemical composition differ with plant species, developmental stage and physiological state. Despite this complexity, cuticular wax consistently serves a critical role in restricting nonstomatal water loss. It also protects the plant against other environmental stresses, including desiccation, UV radiation, microorganisms and insects. Within the broader context of plant responses to abiotic and biotic stresses, our knowledge of the explicit roles of wax crystalline structures and chemical compounds is lacking. In this review, we summarize our current knowledge of wax biosynthesis and regulation in relation to abiotic and biotic stresses and stress responses.
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http://dx.doi.org/10.1111/nph.16571DOI Listing
August 2020

Identification of client iron-sulfur proteins of the chloroplastic NFU2 transfer protein in Arabidopsis thaliana.

J Exp Bot 2020 07;71(14):4171-4187

BPMP, Université de Montpellier, CNRS, INRAE, SupAgro, Montpellier, France.

Iron-sulfur (Fe-S) proteins have critical functions in plastids, notably participating in photosynthetic electron transfer, sulfur and nitrogen assimilation, chlorophyll metabolism, and vitamin or amino acid biosynthesis. Their maturation relies on the so-called SUF (sulfur mobilization) assembly machinery. Fe-S clusters are synthesized de novo on a scaffold protein complex and then delivered to client proteins via several transfer proteins. However, the maturation pathways of most client proteins and their specificities for transfer proteins are mostly unknown. In order to decipher the proteins interacting with the Fe-S cluster transfer protein NFU2, one of the three plastidial representatives found in Arabidopsis thaliana, we performed a quantitative proteomic analysis of shoots, roots, and seedlings of nfu2 plants, combined with NFU2 co-immunoprecipitation and binary yeast two-hybrid experiments. We identified 14 new targets, among which nine were validated in planta using a binary bimolecular fluorescence complementation assay. These analyses also revealed a possible role for NFU2 in the plant response to desiccation. Altogether, this study better delineates the maturation pathways of many chloroplast Fe-S proteins, considerably extending the number of NFU2 clients. It also helps to clarify the respective roles of the three NFU paralogs NFU1, NFU2, and NFU3.
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http://dx.doi.org/10.1093/jxb/eraa166DOI Listing
July 2020

The genome of jojoba (): A taxonomically isolated species that directs wax ester accumulation in its seeds.

Sci Adv 2020 03 11;6(11):eaay3240. Epub 2020 Mar 11.

National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China.

Seeds of the desert shrub, jojoba (), are an abundant, renewable source of liquid wax esters, which are valued additives in cosmetic products and industrial lubricants. Jojoba is relegated to its own taxonomic family, and there is little genetic information available to elucidate its phylogeny. Here, we report the high-quality, 887-Mb genome of jojoba assembled into 26 chromosomes with 23,490 protein-coding genes. The jojoba genome has only the whole-genome triplication (γ) shared among eudicots and no recent duplications. These genomic resources coupled with extensive transcriptome, proteome, and lipidome data helped to define heterogeneous pathways and machinery for lipid synthesis and storage, provided missing evolutionary history information for this taxonomically segregated dioecious plant species, and will support efforts to improve the agronomic properties of jojoba.
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http://dx.doi.org/10.1126/sciadv.aay3240DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7065883PMC
March 2020

Lolium perenne apoplast metabolomics for identification of novel metabolites produced by the symbiotic fungus Epichloë festucae.

New Phytol 2020 07 13;227(2):559-571. Epub 2020 Apr 13.

School of Fundamental Sciences, Massey University, Palmerston North, 4442, New Zealand.

Epichloë festucae is an endophytic fungus that forms a symbiotic association with Lolium perenne. Here we analysed how the metabolome of the ryegrass apoplast changed upon infection of this host with sexual and asexual isolates of E. festucae. A metabolite fingerprinting approach was used to analyse the metabolite composition of apoplastic wash fluid from uninfected and infected L. perenne. Metabolites enriched or depleted in one or both of these treatments were identified using a set of interactive tools. A genetic approach in combination with tandem MS was used to identify a novel product of a secondary metabolite gene cluster. Metabolites likely to be present in the apoplast were identified using MarVis in combination with the BioCyc and KEGG databases, and an in-house Epichloë metabolite database. We were able to identify the known endophyte-specific metabolites, peramine and epichloëcyclins, as well as a large number of unknown markers. To determine whether these methods can be applied to the identification of novel Epichloë-derived metabolites, we deleted a gene encoding a NRPS (lgsA) that is highly expressed in planta. Comparative MS analysis of apoplastic wash fluid from wild-type- vs mutant-infected plants identified a novel Leu/Ile glycoside metabolite present in the former.
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http://dx.doi.org/10.1111/nph.16528DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7317419PMC
July 2020

Insights Into Oxidized Lipid Modification in Barley Roots as an Adaptation Mechanism to Salinity Stress.

Front Plant Sci 2020 4;11. Epub 2020 Feb 4.

Metabolomics Australia, Bio21 Institute, University of Melbourne, Parkville, VIC, Australia.

Lipidomics is an emerging technology, which aims at the global characterization and quantification of lipids within biological matrices including biofluids, cells, whole organs and tissues. The changes in individual lipid molecular species in stress treated plant species and different cultivars can indicate the functions of genes affecting lipid metabolism or lipid signaling. Mass spectrometry-based lipid profiling has been used to track the changes of lipid levels and related metabolites in response to salinity stress. We have developed a comprehensive lipidomics platform for the identification and direct qualification and/or quantification of individual lipid species, including oxidized lipids, which enables a more systematic investigation of peroxidation of individual lipid species in barley roots under salinity stress. This new lipidomics approach has improved with an advantage of analyzing the composition of acyl chains at the molecular level, which facilitates to profile precisely the 18:3-containing diacyl-glycerophosphates and allowed individual comparison of lipids across varieties. Our findings revealed a general decrease in most of the galactolipids in plastid membranes, and an increase of glycerophospholipids and acylated steryl glycosides, which indicate that plastidial and extraplastidial membranes in barley roots ubiquitously tend to form a hexagonal II (HII) phase under salinity stress. In addition, salt-tolerant and salt-sensitive cultivars showed contrasting changes in the levels of oxidized membrane lipids. These results support the hypothesis that salt-induced oxidative damage to membrane lipids can be used as an indication of salt stress tolerance in barley.
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http://dx.doi.org/10.3389/fpls.2020.00001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7011103PMC
February 2020

Disruption of Arabidopsis neutral ceramidases 1 and 2 results in specific sphingolipid imbalances triggering different phytohormone-dependent plant cell death programmes.

New Phytol 2020 04 20;226(1):170-188. Epub 2019 Dec 20.

Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, University of Goettingen, D-37077, Goettingen, Germany.

Sphingolipids act as regulators of programmed cell death (PCD) and the plant defence response. The homeostasis between long-chain base (LCB) and ceramide (Cer) seems to play an important role in executions of PCD. Therefore, deciphering the role of neutral ceramidases (NCER) is crucial to identify the sphingolipid compounds that trigger and execute PCD. We performed comprehensive sphingolipid and phytohormone analyses of Arabidopsis ncer mutants, combined with gene expression profiling and microscopic analyses. While ncer1 exhibited early leaf senescence (developmentally controlled PCD - dPCD) and an increase in hydroxyceramides, ncer2 showed spontaneous cell death (pathogen-triggered PCD-like - pPCD) accompanied by an increase in LCB t18:0 at 35 d, respectively. Loss of NCER1 function resulted in accumulation of jasmonoyl-isoleucine (JA-Ile) in the leaves, whereas disruption of NCER2 was accompanied by higher levels of salicylic acid (SA) and increased sensitivity to Fumonisin B (FB ). All mutants were also found to activate plant defence pathways. These data strongly suggest that NCER1 hydrolyses ceramides whereas NCER2 functions as a ceramide synthase. Our results reveal an important role of NCER in the regulation of both dPCD and pPCD via a tight connection between the phytohormone and sphingolipid levels in these two processes.
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http://dx.doi.org/10.1111/nph.16336DOI Listing
April 2020

Pheophorbide May Regulate Jasmonate Signaling during Dark-Induced Senescence.

Plant Physiol 2020 02 21;182(2):776-791. Epub 2019 Nov 21.

Institute of Plant and Microbial Biology, University of Zürich, 8008 Zürich, Switzerland

Chlorophyll degradation is one of the most visible signs of leaf senescence. During senescence, chlorophyll is degraded in the multistep pheophorbide oxygenase (PAO)/phyllobilin pathway. This pathway is tightly regulated at the transcriptional level, allowing coordinated and efficient remobilization of nitrogen toward sink organs. Using a combination of transcriptome and metabolite analyses during dark-induced senescence of Arabidopsis () mutants deficient in key steps of the PAO/phyllobilin pathway, we show an unanticipated role for one of the pathway intermediates, i.e. pheophorbide Both jasmonic acid-related gene expression and jasmonic acid precursors specifically accumulated in , a mutant deficient in PAO. We propose that pheophorbide , the last intact porphyrin intermediate of chlorophyll degradation and a unique pathway "bottleneck," has been recruited as a signaling molecule of chloroplast metabolic status. Our work challenges the assumption that chlorophyll breakdown is merely a result of senescence, and proposes that the flux of pheophorbide through the pathway acts in a feed-forward loop that remodels the nuclear transcriptome and controls the pace of chlorophyll degradation in senescing leaves.
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http://dx.doi.org/10.1104/pp.19.01115DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6997679PMC
February 2020

The Microalga during Transition from Quiescence to Autotrophy in Response to Nitrogen Availability.

Plant Physiol 2020 02 18;182(2):819-839. Epub 2019 Nov 18.

Michigan State University-United States Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824

The marine microalgae (CCMP1779) is a prolific producer of oil and is considered a viable and sustainable resource for biofuel feedstocks. Nitrogen (N) availability has a strong impact on the physiological status and metabolism of microalgal cells, but the exact nature of this response is poorly understood. To fill this gap we performed transcriptomic profiling combined with cellular and molecular analyses of CCMP1779 during the transition from quiescence to autotrophy. N deprivation-induced quiescence was accompanied by a strong reorganization of the photosynthetic apparatus and changes in the lipid homeostasis, leading to accumulation of triacylglycerol. Cell cycle activation and re-establishment of photosynthetic activity observed in response to resupply of the growth medium with N were accompanied by a rapid degradation of triacylglycerol stored in lipid droplets (LDs). Besides observing LD translocation into vacuoles, we also provide evidence for direct interaction between the LD surface protein (LDSP) and AUTOPHAGY-RELATED8 (ATG8) protein and show a role of microlipophagy in LD turnover in CCMP1779. This knowledge is crucial not only for understanding the fundamental mechanisms controlling the cellular energy homeostasis in microalgal cells but also for development of efficient strategies to achieve higher algal biomass and better microalgal lipid productivity.
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http://dx.doi.org/10.1104/pp.19.00854DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6997683PMC
February 2020

Quantitative Jasmonate Profiling Using a High-Throughput UPLC-NanoESI-MS/MS Method.

Methods Mol Biol 2020 ;2085:169-187

Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, University of Goettingen, Goettingen, Germany.

Jasmonic acid (JA) and its many derivatives-collectively referred as jasmonates-occur ubiquitously in land plants and regulate a wide range of stress-responses and development. Measuring these signaling compounds is complicated by the large number of jasmonate derivatives and the comparatively low concentration of these metabolites in plant tissues. We, here, present a selective and sensitive method consisting of a two-phase extraction coupled with liquid chromatography, nanoelectrospray ionization, and mass spectrometry to determine jasmonate levels in tissues and fluids of various plant species. The application of stable deuterium-labelled standards in combination with authentic standards allows the absolute quantification of a multitude of jasmonates and, additionally, the semi-quantitative analysis of further metabolites from the jasmonate pathway.
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http://dx.doi.org/10.1007/978-1-0716-0142-6_13DOI Listing
December 2020

Erratum for Gerke et al., "Breaking the Silence: Protein Stabilization Uncovers Silenced Biosynthetic Gene Clusters in the Fungus Aspergillus nidulans".

Appl Environ Microbiol 2019 Dec 14;85(23). Epub 2019 Nov 14.

Abteilung für Molekulare Mikrobiologie & Genetik, Institut für Mikrobiologie & Genetik, Georg August Universität, Göttingen, Germany

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http://dx.doi.org/10.1128/AEM.02251-19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6856330PMC
December 2019

Isochorismate-derived biosynthesis of the plant stress hormone salicylic acid.

Science 2019 08;365(6452):498-502

Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, University of Goettingen, D-37077 Goettingen, Germany.

The phytohormone salicylic acid (SA) controls biotic and abiotic plant stress responses. Plastid-produced chorismate is a branch-point metabolite for SA biosynthesis. Most pathogen-induced SA derives from isochorismate, which is generated from chorismate by the catalytic activity of ISOCHORISMATE SYNTHASE1. Here, we ask how and in which cellular compartment isochorismate is converted to SA. We show that in , the pathway downstream of isochorismate requires only two additional proteins: ENHANCED DISEASE SUSCEPTIBILITY5, which exports isochorismate from the plastid to the cytosol, and the cytosolic amidotransferase avrPphB SUSCEPTIBLE3 (PBS3). PBS3 catalyzes the conjugation of glutamate to isochorismate to produce isochorismate-9-glutamate, which spontaneously decomposes into SA and 2-hydroxy-acryloyl--glutamate. The minimal requirement of three compartmentalized proteins controlling unidirectional forward flux may protect the pathway against evolutionary forces and pathogen perturbations.
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http://dx.doi.org/10.1126/science.aaw1720DOI Listing
August 2019

Comprehensive LC-MS-Based Metabolite Fingerprinting Approach for Plant and Fungal-Derived Samples.

Methods Mol Biol 2019 ;1978:167-185

Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, University of Goettingen, Goettingen, Germany.

Liquid chromatography-mass spectrometry (LC-MS)-based nontargeted metabolome approaches aim to detect chemotypes as markers for stress, disease, developmental, or genetic perturbation. Herein, we present a metabolite fingerprinting workflow, which is applicable for the analysis of tissues and fluids derived from plants and fungi. This is based on a broad metabolite coverage by a two-phase extraction and the separate analysis of polar, and nonpolar compounds by positive as well as negative electrospray ionization. For analysis of the resulting comprehensive data sets, the interactive and user-friendly data mining software MarVis-Suite is used. It supports statistical analysis, adduct correction, data merging, as well as visualization of multivariate data. Finally, MarVis shapes marker identification to the organism of interest. Therefore, it provides access to the species-specific databases KEGG and BioCyc and to custom databases tailored by the user.
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http://dx.doi.org/10.1007/978-1-4939-9236-2_11DOI Listing
November 2019

The glycosyltransferase UGT76E1 significantly contributes to 12--glucopyranosyl-jasmonic acid formation in wounded leaves.

J Biol Chem 2019 06 9;294(25):9858-9872. Epub 2019 May 9.

From the Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, University of Goettingen, Goettingen D-37077 and

Jasmonoyl-isoleucine (JA-Ile) is a phytohormone that orchestrates plant defenses in response to wounding, feeding insects, or necrotrophic pathogens. JA-Ile metabolism has been studied intensively, but its catabolism as a potentially important mechanism for the regulation of JA-Ile-mediated signaling is not well-understood. Especially the enzyme(s) responsible for specifically glycosylating 12-hydroxy-jasmonic acid (12-OH-JA) and thereby producing 12--glucopyranosyl-jasmonic acid (12--Glc-JA) is still elusive. Here, we used co-expression analyses of available transcriptomic data, identifying four UDP-dependent glycosyltransferase (UGT) genes as wound-induced and 12-OH-JA-related, namely, , , , and We heterologously expressed and purified the corresponding proteins to determine their individual substrate specificities and kinetic parameters. We then used an metabolite-fingerprinting approach to investigate these proteins in conditions as close as possible to their natural environment, with an emphasis on greatly extending the range of potential substrates. As expected, we found that UGT76E1 and UGT76E2 are 12-OH-JA-UGTs, with UGT76E1 contributing a major UGT activity, as deduced from mutants with abolished or increased gene expression. In contrast, recombinant UGT76E11 acted on an unidentified compound and also glycosylated two other oxylipins, 11-hydroxy-7,9,13-hexadecatrienoic acid (11-HHT) and 13-hydroxy-9,11,15-octadecatrienoic acid (13-HOT), which were also accepted by recombinant UGT76E1, UGT76E2, and UGT76E12 enzymes. UGT76E12 glycosylated 12-OH-JA only to a low extent, but also accepted an artificial hydroxylated fatty acid and low amounts of kaempferol. In conclusion, our findings have elucidated the missing step in the wound-induced synthesis of 12--glucopyranosyl-jasmonic acid in .
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http://dx.doi.org/10.1074/jbc.RA119.007600DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6597828PMC
June 2019

Arabidopsis mlo3 mutant plants exhibit spontaneous callose deposition and signs of early leaf senescence.

Plant Mol Biol 2019 Sep 2;101(1-2):21-40. Epub 2019 May 2.

Unit of Plant Molecular Cell Biology, Institute for Biology I, RWTH Aachen University, Worringerweg 1, 52056, Aachen, Germany.

Key Message: Arabidopsis thaliana mlo3 mutant plants are not affected in pathogen infection phenotypes but-reminiscent of mlo2 mutant plants-exhibit spontaneous callose deposition and signs of early leaf senescence. The family of Mildew resistance Locus O (MLO) proteins is best known for its profound effect on the outcome of powdery mildew infections: when the appropriate MLO protein is absent, the plant is fully resistant to otherwise virulent powdery mildew fungi. However, most members of the MLO protein family remain functionally unexplored. Here, we investigate Arabidopsis thaliana MLO3, the closest relative of AtMLO2, AtMLO6 and AtMLO12, which are the Arabidopsis MLO genes implicated in the powdery mildew interaction. The co-expression network of AtMLO3 suggests association of the gene with plant defense-related processes such as salicylic acid homeostasis. Our extensive analysis shows that mlo3 mutants are unaffected regarding their infection phenotype upon challenge with the powdery mildew fungi Golovinomyces orontii and Erysiphe pisi, the oomycete Hyaloperonospora arabidopsidis, and the bacterial pathogen Pseudomonas syringae (the latter both in terms of basal and systemic acquired resistance), indicating that the protein does not play a major role in the response to any of these pathogens. However, mlo3 genotypes display spontaneous callose deposition as well as signs of early senescence in 6- or 7-week-old rosette leaves in the absence of any pathogen challenge, a phenotype that is reminiscent of mlo2 mutant plants. We hypothesize that de-regulated callose deposition in mlo3 genotypes might be the result of a subtle transient aberration of salicylic acid-jasmonic acid homeostasis during development.
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http://dx.doi.org/10.1007/s11103-019-00877-zDOI Listing
September 2019