Publications by authors named "Mélanie Morel-Rouhier"

21 Publications

  • Page 1 of 1

Diversity of Omega Glutathione Transferases in mushroom-forming fungi revealed by phylogenetic, transcriptomic, biochemical and structural approaches.

Fungal Genet Biol 2021 Mar 12;148:103506. Epub 2021 Jan 12.

Université de Lorraine, CNRS, CRM2, Nancy, France. Electronic address:

The Omega class of glutathione transferases (GSTs) forms a distinct class within the cytosolic GST superfamily because most of them possess a catalytic cysteine residue. The human GST Omega 1 isoform was first characterized twenty years ago, but it took years of work to clarify the roles of the human isoforms. Concerning the kingdom of fungi, little is known about the cellular functions of Omega glutathione transferases (GSTOs), although they are widely represented in some of these organisms. In this study, we re-assess the phylogeny and the classification of GSTOs based on 240 genomes of mushroom-forming fungi (Agaricomycetes). We observe that the number of GSTOs is not only extended in the order of Polyporales but also in other orders such as Boletales. Our analysis leads to a new classification in which the fungal GSTOs are divided into two Types A and B. The catalytic residue of Type-A is either cysteine or serine, while that of Type-B is cysteine. The present study focuses on Trametes versicolor GSTO isoforms that possess a catalytic cysteine residue. Transcriptomic data show that Type-A GSTOs are constitutive enzymes while Type-B are inducible ones. The crystallographic analysis reveals substantial structural differences between the two types while they have similar biochemical profiles in the tested conditions. Additionally, these enzymes have the ability to bind antioxidant molecules such as wood polyphenols in two possible binding sites as observed from X-ray structures. The multiplication of GSTOs could allow fungal organisms to adapt more easily to new environments.
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http://dx.doi.org/10.1016/j.fgb.2020.103506DOI Listing
March 2021

OSIP1 is a self-assembling DUF3129 protein required to protect fungal cells from toxins and stressors.

Environ Microbiol 2021 Mar 12;23(3):1594-1607. Epub 2021 Jan 12.

Université de Lorraine, INRAE, Interactions Arbres/Micro-organismes (IAM), UMR 1136, Nancy, 54000, France.

Secreted proteins are key players in fungal physiology and cell protection against external stressing agents and antifungals. Oak stress-induced protein 1 (OSIP1) is a fungal-specific protein with unknown function. By using Podospora anserina and Phanerochaete chrysosporium as models, we combined both in vivo functional approaches and biophysical characterization of OSIP1 recombinant protein. The P. anserina OSIP1 mutant showed an increased sensitivity to the antifungal caspofungin compared to the wild type. This correlated with the production of a weakened extracellular exopolysaccharide/protein matrix (ECM). Since the recombinant OSIP1 from P. chrysosporium self-assembled as fibers and was capable of gelation, it is likely that OSIP1 is linked to ECM formation that acts as a physical barrier preventing drug toxicity. Moreover, compared to the wild type, the OSIP1 mutant was more sensitive to oak extractives including chaotropic phenols and benzenes. It exhibited a strongly modified secretome pattern and an increased production of proteins associated to the cell-wall integrity signalling pathway, when grown on oak sawdust. This demonstrates that OSIP1 has also an important role in fungal resistance to extractive-induced stress.
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http://dx.doi.org/10.1111/1462-2920.15381DOI Listing
March 2021

Oxidized glutathione promotes association between eukaryotic translation elongation factor 1Bγ and Ure2p glutathione transferase from Phanerochaete chrysosporium.

FEBS J 2020 Oct 30. Epub 2020 Oct 30.

Université de Lorraine, Nancy, France.

The eukaryotic translation elongation factor 1Bγ (eEF1Bγ) is an atypical member of the glutathione transferase (GST) superfamily. Contrary to more classical GSTs having a role in toxic compound detoxification, eEF1Bγ is suggested to act as a scaffold protein, anchoring the elongation factor complex EF1B to the endoplasmic reticulum. In this study, we show that eEF1Bγ from the basidiomycete Phanerochaete chrysosporium is fully active as a glutathione transferase in vitro and undergoes conformational changes upon binding of oxidized glutathione. Using real-time analyses of biomolecular interactions, we show that GSSG allows eEF1Bγ to physically interact with other GSTs from the Ure2p class, opening new perspectives for a better understanding of the role of eEF1Bγ in cellular oxidative stress response.
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http://dx.doi.org/10.1111/febs.15614DOI Listing
October 2020

Glutathione Transferases: Surrogate Targets for Discovering Biologically Active Compounds.

J Nat Prod 2020 10 1;83(10):2960-2966. Epub 2020 Oct 1.

Faculté des sciences, Université de Lorraine, INRAE, IAM, F-54000 Nancy, France.

Glutathione transferases comprise a large class of multifunctional enzymes, some involved in detoxification pathways. Since these enzymes are able to interact with potentially toxic molecules, they could be used as targets to screen for compounds with biological activity. To test this hypothesis, glutathione transferases (GSTs) from the white-rot fungus have been used to screen for antifungal molecules from a library of tropical wood extracts. The interactions between a set of six GSTs from the omega class and 116 extracts from 21 tropical species were quantified using a high-throughput thermal shift assay. A correlation between these interactions and the antifungal properties of the tested extracts was demonstrated. This approach has been extended to the fractionation of an extract and led to the detection of maackiain and lapachol in this wood. Altogether, the present results supported the hypothesis that such detoxification enzymes could be used to detect biologically active molecules.
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http://dx.doi.org/10.1021/acs.jnatprod.0c00480DOI Listing
October 2020

Conserved white-rot enzymatic mechanism for wood decay in the Basidiomycota genus Pycnoporus.

DNA Res 2020 Apr;27(2)

INRAE, UMR1163, Biodiversity and Biotechnology of Fungi, Aix Marseille University, 13009 Marseille, France.

White-rot (WR) fungi are pivotal decomposers of dead organic matter in forest ecosystems and typically use a large array of hydrolytic and oxidative enzymes to deconstruct lignocellulose. However, the extent of lignin and cellulose degradation may vary between species and wood type. Here, we combined comparative genomics, transcriptomics and secretome proteomics to identify conserved enzymatic signatures at the onset of wood-decaying activity within the Basidiomycota genus Pycnoporus. We observed a strong conservation in the genome structures and the repertoires of protein-coding genes across the four Pycnoporus species described to date, despite the species having distinct geographic distributions. We further analysed the early response of P. cinnabarinus, P. coccineus and P. sanguineus to diverse (ligno)-cellulosic substrates. We identified a conserved set of enzymes mobilized by the three species for breaking down cellulose, hemicellulose and pectin. The co-occurrence in the exo-proteomes of H2O2-producing enzymes with H2O2-consuming enzymes was a common feature of the three species, although each enzymatic partner displayed independent transcriptional regulation. Finally, cellobiose dehydrogenase-coding genes were systematically co-regulated with at least one AA9 lytic polysaccharide monooxygenase gene, indicative of enzymatic synergy in vivo. This study highlights a conserved core white-rot fungal enzymatic mechanism behind the wood-decaying process.
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http://dx.doi.org/10.1093/dnares/dsaa011DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7406137PMC
April 2020

A reverse chemical ecology approach to explore wood natural durability.

Microb Biotechnol 2020 09 25;13(5):1673-1677. Epub 2020 Mar 25.

Université de Lorraine, INRAE, IAM, Nancy, France.

The natural durability of wood species, defined as their inherent resistance to wood-destroying agents, is a complex phenomenon depending on many biotic and abiotic factors. Besides the presence of recalcitrant polymers, the presence of compounds with antimicrobial properties is known to be important to explain wood durability. Based on the advancement in our understanding of fungal detoxification systems, a reverse chemical ecology approach was proposed to explore wood natural durability using fungal glutathione transferases. A set of six glutathione transferases from the white-rot Trametes versicolor were used as targets to test wood extracts from seventeen French Guiana neotropical species. Fluorescent thermal shift assays quantified interactions between fungal glutathione transferases and these extracts. From these data, a model combining this approach and wood density significantly predicts the wood natural durability of the species tested previously using long-term soil bed tests. Overall, our findings confirm that detoxification systems could be used to explore the chemical environment encountered by wood-decaying fungi and also wood natural durability.
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http://dx.doi.org/10.1111/1751-7915.13540DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7415366PMC
September 2020

Target Of Rapamycin pathway in the white-rot fungus Phanerochaete chrysosporium.

PLoS One 2020 20;15(2):e0224776. Epub 2020 Feb 20.

Université de Lorraine, INRA, IAM, France.

The Target Of Rapamycin (TOR) signaling pathway is known to regulate growth in response to nutrient availability and stress in eukaryotic cells. In the present study, we have investigated the TOR pathway in the white-rot fungus Phanerochaete chrysosporium. Inhibition of TOR activity by rapamycin affects conidia germination and hyphal growth highlighting the conserved mechanism of susceptibility to rapamycin. Interestingly, the secreted protein content is also affected by the rapamycin treatment. Finally, homologs of the components of TOR pathway can be identified in P. chrysosporium. Altogether, those results indicate that the TOR pathway of P. chrysosporium plays a central role in this fungus.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0224776PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7032718PMC
May 2020

The structure of Trametes versicolor glutathione transferase Omega 3S bound to its conjugation product glutathionyl-phenethylthiocarbamate reveals plasticity of its active site.

Protein Sci 2019 06 29;28(6):1143-1150. Epub 2019 Apr 29.

Université de Lorraine, CNRS, CRM2, Nancy, France.

Trametes versicolor glutathione transferase Omega 3S (TvGSTO3S) catalyzes the conjugation of isothiocyanates (ITC) with glutathione (GSH). Previously, this isoform was investigated in depth both biochemically and structurally. Structural analysis of complexes revealed the presence of a GSH binding site (G site) and a deep hydrophobic binding site (H site) able to bind plant polyphenols. In the present study, crystals of apo TvGSTO3S were soaked with glutathionyl-phenethylthiocarbamate, the product of the reaction between GSH and phenethyl isothiocyanate (PEITC). On the basis of this crystal structure, we show that the phenethyl moiety binds in a new site at loop β -α while the glutathionyl part exhibits a particular conformation that occupies both the G site and the entrance to the H site. This binding mode is allowed by a conformational change of the loop β -α at the enzyme active site. It forms a hydrophobic slit that stabilizes the phenethyl group at a distinct site from the previously described H site. Structural comparison of TvGSTO3S with drosophila DmGSTD2 suggests that this flexible loop could be the region that binds PEITC for both isoforms. These structural features are discussed in a catalytic context.
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http://dx.doi.org/10.1002/pro.3620DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6511745PMC
June 2019

Oak extractive-induced stress reveals the involvement of new enzymes in the early detoxification response of Phanerochaete chrysosporium.

Environ Microbiol 2018 10 5;20(10):3890-3901. Epub 2018 Oct 5.

Université de Lorraine, UMR1136 INRA-Université de Lorraine "Interactions Arbres/Micro-organismes", Faculté des Sciences et Technologies, Vandoeuvre-lès-Nancy Cedex, France.

Extensive evidence showed that the efficiency of fungal wood degradation is closely dependent on their ability to cope with the myriad of putative toxic compounds called extractives released during this process. By analysing global gene expression of Phanerochaete chrysosporium after short oak extractive treatment (1, 3 and 6 h), we show that the early molecular response of the fungus concerns first mitochondrial stress rescue followed by the oxidation and finally conjugation of the compounds. During these early responses, the lignolytic degradative system is not induced, rather some small secreted proteins could play an important role in cell protection or signaling. By focusing on the functional characterization of an hitherto uncharacterized glutathione transferase, we show that this enzyme interacts with wood molecules suggesting that it could be involved in the detoxification of some of them, or act as a scavenger to prevent their cytosolic toxicity and favour their transport.
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http://dx.doi.org/10.1111/1462-2920.14409DOI Listing
October 2018

Trametes versicolor glutathione transferase Xi 3, a dual Cys-GST with catalytic specificities of both Xi and Omega classes.

FEBS Lett 2018 09 6;592(18):3163-3172. Epub 2018 Sep 6.

CNRS, CRM2, Université de Lorraine, Nancy, France.

Glutathione transferases (GSTs) from the Xi and Omega classes have a catalytic cysteine residue, which gives them reductase activities. Until now, they have been assigned distinct substrates. While Xi GSTs specifically reduce glutathionyl-(hydro)quinones, Omega GSTs are specialized in the reduction of glutathionyl-acetophenones. Here, we present the biochemical and structural analysis of TvGSTX1 and TvGSTX3 isoforms from the wood-degrading fungus Trametes versicolor. TvGSTX1 reduces GS-menadione as expected, while TvGSTX3 reduces both Xi and Omega substrates. An in-depth structural analysis indicates a broader active site for TvGSTX3 due to specific differences in the nature of the residues situated in the C-terminal helix α9. This feature could explain the catalytic duality of TvGSTX3. Based on phylogenetic analysis, we propose that this duality might exist in saprophytic fungi and ascomycetes.
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http://dx.doi.org/10.1002/1873-3468.13224DOI Listing
September 2018

Molecular recognition of wood polyphenols by phase II detoxification enzymes of the white rot Trametes versicolor.

Sci Rep 2018 05 31;8(1):8472. Epub 2018 May 31.

Université de Lorraine, INRA, IAM, Nancy, France.

Wood decay fungi have complex detoxification systems that enable them to cope with secondary metabolites produced by plants. Although the number of genes encoding for glutathione transferases is especially expanded in lignolytic fungi, little is known about their target molecules. In this study, by combining biochemical, enzymatic and structural approaches, interactions between polyphenols and six glutathione transferases from the white-rot fungus Trametes versicolor have been demonstrated. Two isoforms, named TvGSTO3S and TvGSTO6S have been deeply studied at the structural level. Each isoform shows two distinct ligand-binding sites, a narrow L-site at the dimer interface and a peculiar deep hydrophobic H-site. In TvGSTO3S, the latter appears optimized for aromatic ligand binding such as hydroxybenzophenones. Affinity crystallography revealed that this H-site retains the flavonoid dihydrowogonin from a partially purified wild-cherry extract. Besides, TvGSTO6S binds two molecules of the flavonoid naringenin in the L-site. These data suggest that TvGSTO isoforms could interact with plant polyphenols released during wood degradation.
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http://dx.doi.org/10.1038/s41598-018-26601-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5981210PMC
May 2018

Enzyme Activities of Two Recombinant Heme-Containing Peroxidases, DyP1 and VP2, Identified from the Secretome of Trametes versicolor.

Appl Environ Microbiol 2018 04 2;84(8). Epub 2018 Apr 2.

INRA, Aix-Marseille Université, UMR1163, Biodiversité et Biotechnologie Fongiques, Marseille, France

is a wood-inhabiting agaricomycete known for its ability to cause strong white-rot decay on hardwood and for its high tolerance of phenolic compounds. The goal of the present work was to gain insights into the molecular biology and biochemistry of the heme-including class II and dye-decolorizing peroxidases secreted by this fungus. Proteomic analysis of the secretome of BRFM 1218 grown on oak wood revealed a set of 200 secreted proteins, among which were the dye-decolorizing peroxidase DyP1 and the versatile peroxidase VP2. Both peroxidases were heterologously produced in , biochemically characterized, and tested for the ability to oxidize complex substrates. Both peroxidases were found to be active against several substrates under acidic conditions, and DyP1 was very stable over a relatively large pH range of 2.0 to 6.0, while VP2 was more stable at pH 5.0 to 6.0 only. The thermostability of both enzymes was also tested, and DyP1 was globally found to be more stable than VP2. After 180 min of incubation at temperatures ranging from 30 to 50°C, the activity of VP2 drastically decreased, with 10 to 30% of the initial activity retained. Under the same conditions, DyP1 retained 20 to 80% of its enzyme activity. The two proteins were catalytically characterized, and VP2 was shown to accept a wider range of reducing substrates than DyP1. Furthermore, both enzymes were found to be active against two flavonoids, quercetin and catechin, found in oak wood, with VP2 displaying more rapid oxidation of the two compounds. They were tested for the ability to decolorize five industrial dyes, and VP2 presented a greater ability to oxidize and decolorize the dye substrates than DyP1. is a wood-inhabiting agaricomycete known for its ability to cause strong white-rot decay on hardwood and for its high tolerance of phenolic compounds. Among white-rot fungi, the basidiomycete has been extensively studied for its ability to degrade wood, specifically lignin, thanks to an extracellular oxidative enzymatic system. The corresponding oxidative system was previously studied in several works for classical lignin and manganese peroxidases, and in this study, two new components of the oxidative system of , one dye-decolorizing peroxidase and one versatile peroxidase, were biochemically characterized in depth and compared to other fungal peroxidases.
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http://dx.doi.org/10.1128/AEM.02826-17DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5881066PMC
April 2018

Crystal Structure of Saccharomyces cerevisiae ECM4, a Xi-Class Glutathione Transferase that Reacts with Glutathionyl-(hydro)quinones.

PLoS One 2016 13;11(10):e0164678. Epub 2016 Oct 13.

Université de Lorraine, CRM2, UMR 7036, F-54500 Vandœuvre-lès-Nancy, France.

Glutathionyl-hydroquinone reductases (GHRs) belong to the recently characterized Xi-class of glutathione transferases (GSTXs) according to unique structural properties and are present in all but animal kingdoms. The GHR ScECM4 from the yeast Saccharomyces cerevisiae has been studied since 1997 when it was found to be potentially involved in cell-wall biosynthesis. Up to now and in spite of biological studies made on this enzyme, its physiological role remains challenging. The work here reports its crystallographic study. In addition to exhibiting the general GSTX structural features, ScECM4 shows extensions including a huge loop which contributes to the quaternary assembly. These structural extensions are probably specific to Saccharomycetaceae. Soaking of ScECM4 crystals with GS-menadione results in a structure where glutathione forms a mixed disulfide bond with the cysteine 46. Solution studies confirm that ScECM4 has reductase activity for GS-menadione in presence of glutathione. Moreover, the high resolution structures allowed us to propose new roles of conserved residues of the active site to assist the cysteine 46 during the catalytic act.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0164678PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5063366PMC
May 2017

Secretion of small proteins is species-specific within Aspergillus sp.

Microb Biotechnol 2017 03 7;10(2):323-329. Epub 2016 May 7.

Faculté des Sciences et Technologies BP 70239, UMR1136 INRA-Université de Lorraine "Interactions Arbres/Micro-organismes", Université de Lorraine, Vandoeuvre-lès-Nancy Cedex, F-54506, France.

Small secreted proteins (SSP) have been defined as proteins containing a signal peptide and a sequence of less than 300 amino acids. In this analysis, we have compared the secretion pattern of SSPs among eight aspergilli species in the context of plant biomass degradation and have highlighted putative interesting candidates that could be involved in the degradative process or in the strategies developed by fungi to resist the associated stress that could be due to the toxicity of some aromatic compounds or reactive oxygen species released during degradation. Among these candidates, for example, some stress-related superoxide dismutases or some hydrophobic surface binding proteins (HsbA) are specifically secreted according to the species . Since these latter proteins are able to recruit lytic enzymes to the surface of hydrophobic solid materials and promote their degradation, a synergistic action of HsbA with the degradative system may be considered and need further investigations. These SSPs could have great applications in biotechnology by optimizing the efficiency of the enzymatic systems for biomass degradation.
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http://dx.doi.org/10.1111/1751-7915.12361DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5328806PMC
March 2017

The GSTome Reflects the Chemical Environment of White-Rot Fungi.

PLoS One 2015 1;10(10):e0137083. Epub 2015 Oct 1.

Université de Lorraine, Interactions Arbres-Microorganismes, UMR1136, F-54500, Vandoeuvre-lès-Nancy, France; INRA, Interactions Arbres-Microorganismes, UMR1136, F-54280, Champenoux, France.

White-rot fungi possess the unique ability to degrade and mineralize all the different components of wood. In other respects, wood durability, among other factors, is due to the presence of extractives that are potential antimicrobial molecules. To cope with these molecules, wood decay fungi have developed a complex detoxification network including glutathione transferases (GST). The interactions between GSTs from two white-rot fungi, Trametes versicolor and Phanerochaete chrysosporium, and an environmental library of wood extracts have been studied. The results demonstrate that the specificity of these interactions is closely related to the chemical composition of the extracts in accordance with the tree species and their localization inside the wood (sapwood vs heartwood vs knotwood). These data suggest that the fungal GSTome could reflect the chemical environment encountered by these fungi during wood degradation and could be a way to study their adaptation to their way of life.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0137083PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4591263PMC
June 2016

Evolutionary divergence of Ure2pA glutathione transferases in wood degrading fungi.

Fungal Genet Biol 2015 Oct 5;83:103-112. Epub 2015 Sep 5.

Université de Lorraine, UMR 1136 Interactions Arbres/Microorganismes, F-54506 Vandoeuvre-lès-Nancy, France; INRA, UMR 1136 Interactions Arbres/Microorganismes, F-54280 Champenoux, France. Electronic address:

The intracellular systems of detoxification are crucial for the survival of wood degrading fungi. Within these systems, glutathione transferases could play a major role since this family of enzymes is specifically extended in lignolytic fungi. In particular the Ure2p class represents one third of the total GST number in Phanerochaete chrysosporium. These proteins have been phylogenetically split into two subclasses called Ure2pA and Ure2pB. Ure2pB can be classified as Nu GSTs because of shared structural and functional features with previously characterized bacterial isoforms. Ure2pA can rather be qualified as Nu-like GSTs since they exhibit a number of differences. Ure2pA possess a classical transferase activity, a more divergent catalytic site and a higher structural flexibility for some of them, compared to Nu GSTs. The characterization of four members of this Ure2pA subclass (PcUre2pA4, PcUre2pA5, PcUre2pA6 and PcUre2pA8) revealed specific functional and structural features, suggesting that these enzymes have rapidly evolved and differentiated, probably to adapt to the complex chemical environment associated with wood decomposition.
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http://dx.doi.org/10.1016/j.fgb.2015.09.002DOI Listing
October 2015

Characterization of glutathione transferases involved in the pathogenicity of Alternaria brassicicola.

BMC Microbiol 2015 Jun 18;15:123. Epub 2015 Jun 18.

Université d'Angers, UMR 1345 IRHS, SFR 4207 QUASAV, 2 Bd Lavoisier, Angers cedex, F-49045, France.

Background: Glutathione transferases (GSTs) represent an extended family of multifunctional proteins involved in detoxification processes and tolerance to oxidative stress. We thus anticipated that some GSTs could play an essential role in the protection of fungal necrotrophs against plant-derived toxic metabolites and reactive oxygen species that accumulate at the host-pathogen interface during infection.

Results: Mining the genome of the necrotrophic Brassica pathogen Alternaria brassicicola for glutathione transferase revealed 23 sequences, 17 of which could be clustered into the main classes previously defined for fungal GSTs and six were 'orphans'. Five isothiocyanate-inducible GSTs from five different classes were more thoroughly investigated. Analysis of their catalytic properties revealed that two GSTs, belonging to the GSTFuA and GTT1 classes, exhibited GSH transferase activity with isothiocyanates (ITC) and peroxidase activity with cumene hydroperoxide, respectively. Mutant deficient for these two GSTs were however neither more susceptible to ITC nor less aggressive than the wild-type parental strain. By contrast mutants deficient for two other GSTs, belonging to the Ure2pB and GSTO classes, were distinguished by their hyper-susceptibility to ITC and low aggressiveness against Brassica oleracea. In particular AbGSTO1 could participate in cell tolerance to ITC due to its glutathione-dependent thioltransferase activity. The fifth ITC-inducible GST belonged to the MAPEG class and although it was not possible to produce the soluble active form of this protein in a bacterial expression system, the corresponding deficient mutant failed to develop normal symptoms on host plant tissues.

Conclusions: Among the five ITC-inducible GSTs analyzed in this study, three were found essential for full aggressiveness of A. brassicicola on host plant. This, to our knowledge is the first evidence that GSTs might be essential virulence factors for fungal necrotrophs.
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http://dx.doi.org/10.1186/s12866-015-0462-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4470081PMC
June 2015

Glutathionyl-hydroquinone reductases from poplar are plastidial proteins that deglutathionylate both reduced and oxidized glutathionylated quinones.

FEBS Lett 2015 Jan 29;589(1):37-44. Epub 2014 Nov 29.

Université de Lorraine, Interactions Arbres - Microorganismes, UMR1136, F-54500 Vandœuvre-lès-Nancy, France; INRA, Interactions Arbres - Microorganismes, UMR1136, F-54280 Champenoux, France. Electronic address:

Glutathionyl-hydroquinone reductases (GHRs) catalyze the deglutathionylation of quinones via a catalytic cysteine. The two GHR genes in the Populus trichocarpa genome, Pt-GHR1 and Pt-GHR2, are primarily expressed in reproductive organs. Both proteins are localized in plastids. More specifically, Pt-GHR2 localizes in nucleoids. At the structural level, Pt-GHR1 adopts a typical GHR fold, with a dimerization interface comparable to that of the bacterial and fungal GHR counterparts. Pt-GHR1 catalyzes the deglutathionylation of both reduced and oxidized glutathionylated quinones, but the enzyme is more catalytically efficient with the reduced forms.
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http://dx.doi.org/10.1016/j.febslet.2014.11.021DOI Listing
January 2015

Transcriptomic responses of Phanerochaete chrysosporium to oak acetonic extracts: focus on a new glutathione transferase.

Appl Environ Microbiol 2014 Oct 8;80(20):6316-27. Epub 2014 Aug 8.

Université de Lorraine, IAM, UMR 1136, IFR 110 EFABA, Champenoux, France INRA, IAM, UMR 1136, Vandoeuvre-les-Nancy, France

The first steps of wood degradation by fungi lead to the release of toxic compounds known as extractives. To better understand how lignolytic fungi cope with the toxicity of these molecules, a transcriptomic analysis of Phanerochaete chrysosporium genes was performed in the presence of oak acetonic extracts. It reveals that in complement to the extracellular machinery of degradation, intracellular antioxidant and detoxification systems contribute to the lignolytic capabilities of fungi, presumably by preventing cellular damages and maintaining fungal health. Focusing on these systems, a glutathione transferase (P. chrysosporium GTT2.1 [PcGTT2.1]) has been selected for functional characterization. This enzyme, not characterized so far in basidiomycetes, has been classified first as a GTT2 compared to the Saccharomyces cerevisiae isoform. However, a deeper analysis shows that the GTT2.1 isoform has evolved functionally to reduce lipid peroxidation by recognizing high-molecular-weight peroxides as substrates. Moreover, the GTT2.1 gene has been lost in some non-wood-decay fungi. This example suggests that the intracellular detoxification system evolved concomitantly with the extracellular ligninolytic machinery in relation to the capacity of fungi to degrade wood.
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http://dx.doi.org/10.1128/AEM.02103-14DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4178660PMC
October 2014

Diversification of fungal specific class a glutathione transferases in saprotrophic fungi.

PLoS One 2013 20;8(11):e80298. Epub 2013 Nov 20.

Université de Lorraine, IAM, UMR 1136, IFR 110 EFABA, Vandoeuvre-les-Nancy, France ; INRA, IAM, UMR 1136, Champenoux, France ; Laboratoire de biotechnologie, Pôle Biotechnologie et Sylviculture Avancée, FCBA, Campus Forêt-Bois de Pierroton, Cestas, France.

Glutathione transferases (GSTs) form a superfamily of multifunctional proteins with essential roles in cellular detoxification processes and endogenous metabolism. The distribution of fungal-specific class A GSTs was investigated in saprotrophic fungi revealing a recent diversification within this class. Biochemical characterization of eight GSTFuA isoforms from Phanerochaete chrysosporium and Coprinus cinereus demonstrated functional diversity in saprotrophic fungi. The three-dimensional structures of three P. chrysosporium isoforms feature structural differences explaining the functional diversity of these enzymes. Competition experiments between fluorescent probes, and various molecules, showed that these GSTs function as ligandins with various small aromatic compounds, derived from lignin degradation or not, at a L-site overlapping the glutathione binding pocket. By combining genomic data with structural and biochemical determinations, we propose that this class of GST has evolved in response to environmental constraints induced by wood chemistry.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0080298PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3835915PMC
September 2014

Atypical features of a Ure2p glutathione transferase from Phanerochaete chrysosporium.

FEBS Lett 2013 Jul 24;587(14):2125-30. Epub 2013 May 24.

Université de Lorraine, IAM, UMR 1136, IFR 110 EFABA,Vandoeuvre-lès-Nancy F-54506, France.

Glutathione transferases (GSTs) are known to transfer glutathione onto small hydrophobic molecules in detoxification reactions. The GST Ure2pB1 from Phanerochaete chrysosporium exhibits atypical features, i.e. the presence of two glutathione binding sites and a high affinity towards oxidized glutathione. Moreover, PcUre2pB1 is able to efficiently deglutathionylate GS-phenacylacetophenone. Catalysis is not mediated by the cysteines of the protein but rather by the one of glutathione and an asparagine residue plays a key role in glutathione stabilization. Interestingly PcUre2pB1 interacts in vitro with a GST of the omega class. These properties are discussed in the physiological context of wood degrading fungi.
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http://dx.doi.org/10.1016/j.febslet.2013.05.031DOI Listing
July 2013