Un enfoque multiómico permite entender cómo Pleurotus eryngii transforma el material lignocelulósico no leñoso

1 p.Pleurotus eryngii es un hongo de prados y pastizales de interés biotecnológico por su capacidad para transformar el material lignocelulósico no leñoso. En este estudio combinamos análisis transcriptómicos, exoproteómicos y metabolómicos con objeto de ofrecer una explicación sobre los aspectos enzimáticos relacionados con la degradación de la paja de trigo. Durante la fase temprana de crecimiento encontramos un conjunto de enzimas extracelulares inducidas y constitutivas formado por glicosil hidrolasas, polisacárido liasas y carbohidrato esterasas activas sobre polisacáridos,lacasas activas sobre lignina, y una cantidad sorprendente de aril-alcohol oxidasas (AAOs). A tiempos largos identificamos una mayor diversidad y abundancia de enzimas, representada por oxidorreductasas implicadas en la despolimerización de celulosa y lignina, muchas de ellas inducidas desde la fase temprana de crecimiento. Estas enzimas oxidativas incluyeron monooxigenasas líticas de polisacáridos (LPMOs), celobiosa deshidrogenasa implicada en la activación de las LPMOs, y peroxidasas ligninolíticas (principalmente manganeso peroxidasas), junto a una gran abundancia de AAOs productoras de H2O2. Algunas de las enzimas más relevantes activas sobre polisacáridos aparecieron unidas a módulos de unión a celulosa. Esto se relacionó con el hábitat de P. eryngii.También elucidamos aspectos del catabolismo intracelular de compuestos aromáticos, un tema poco investigado en los basidiomicetos degradadores de lignina. Este enfoque multiómico revela que, aunque la descomposición de la paja de trigo no se traduce en grandes cambios (de acuerdo con análisis de 2D-NMR, entre otros), se produce la activación de enzimas hidrolíticas y oxidativas de gran interés biotecnológico en procesos dirigidos al aprovechamiento de la biomasa vegetal.Proyectos GENOBIOREF (BIO2017-86559-R), MICINN (cofinanciado con fondos FEDER); PIE-202120E019 y PIE-201620E081, CSIC; y contratos DE-AC02-05CH11231 y DE-AC36-08GO28308, U.S. DOEPeer reviewe

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

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.Peer reviewe

Clonostachys saulensis (Bionectriaceae, Hypocreales), a new species from French Guiana

Clonostachys saulensis sp. nov. is described and illustrated based on a collection on bark of dead liana in French Guiana. this species is placed in Clonostachys (= Bionectria) based on its clonostachys-like asexual morph, ascomata not changing colour in 3% Koh or lactic acid and phylogenetic comparison of itS sequences with known species of Clonostachys. Clonostachys saulensis is primarily characterized by nonstromatic,smooth, pale brown, globose ascomata coated with a whitish powdery scurf from base up to half height and turning blackish upon drying. Based on comparison of morphological characteristics of sexualasexual morphs and molecular data with known species, C. saulensis is proposed as a new species. .Clonostachys saulensis sp. nov. est décrite et illustrée d’après une récolte effectuée sur écorce de liane morte en Guyane française. cette espèce est placée dans le genre Clonostachys (= Bionectria) d’après sa forme asexuée de type clonostachys, les ascomes ne changeant pas de couleur dans Koh à 3% ou dans l’acide lactique et la comparaison phylogénétique des séquences itS avec les espèces connues de Clonostachys. Clonostachys saulensis est principalement caractérisée par des ascomes globuleux, sans stroma, brun pâle, couverts d’une pellicule poudreuse blanchâtre de la base jusqu’à la moitié de la hauteur, devenant noirâtres en séchant. en se fondant sur la comparaison des caractères morphologiques et des données moléculaires avec les espèces connues, C. saulensis est proposée comme une nouvelle espèce

Clonostachys saulensis (Bionectriaceae, Hypocreales), a new species from French Guiana

Appreciation to Parc National Amazonien de Guyane (PNAG) for having organized the field trip to SaülClonostachys saulensis sp. nov. is described and illustrated based on a collection on bark of deadliana in French Guiana. this species is placed in Clonostachys (= Bionectria) based on its clonostachys-likeasexual morph, ascomata not changing colour in 3% Koh or lactic acid and phylogenetic comparison of itSsequences with known species of Clonostachys. Clonostachys saulensis is primarily characterized by nonstromatic,smooth, pale brown, globose ascomata coated with a whitish powdery scurf from base up to halfheight and turning blackish upon drying. Based on comparison of morphological characteristics of sexualasexualmorphs and molecular data with known species, C. saulensis is proposed as a new species..Clonostachys saulensis sp. nov. est décrite et illustrée d’après une récolte effectuée sur écorce deliane morte en Guyane française. cette espèce est placée dans le genre Clonostachys (= Bionectria) d’aprèssa forme asexuée de type clonostachys, les ascomes ne changeant pas de couleur dans Koh à 3% ou dansl’acide lactique et la comparaison phylogénétique des séquences itS avec les espèces connues de Clonostachys.Clonostachys saulensis est principalement caractérisée par des ascomes globuleux, sans stroma, brunpâle, couverts d’une pellicule poudreuse blanchâtre de la base jusqu’à la moitié de la hauteur, devenant noirâtresen séchant. en se fondant sur la comparaison des caractères morphologiques et des données moléculairesavec les espèces connues, C. saulensis est proposée comme une nouvelle espèce

Inhibition of a NF-κB/Diap1 Pathway by PGRP-LF Is Required for Proper Apoptosis during Drosophila Development

International audienceNF-κB pathways are key signaling cascades of the Drosophila innate immune response. One of them, the Immune Deficiency (IMD) pathway, is under a very tight negative control. Although molecular brakes exist at each step of this signaling module from ligand availability to transcriptional regulation, it remains unknown whether repressors act in the same cells or tissues and if not, what is rationale behind this spatial specificity. We show here that the negative regulator of IMD pathway PGRP-LF is epressed in ectodermal derivatives. We provide evidence that, in the absence of any immune elicitor, PGRP-LF loss-of-function mutants, display a constitutive NF-κB/IMD activation specifically in ectodermal tissues leading to genitalia and tergite malformations. In agreement with previous data showing that proper development of these structures requires induction of apoptosis, we show that ectopic activation of NF-κB/IMD signaling leads to apoptosis inhibition in both genitalia and tergite primordia. We demonstrate that NF-κB/IMD signaling antagonizes apoptosis by up-regulating expression of the anti-apoptotic protein Diap1. Altogether these results show that, in the complete absence of infection, the negative regulation of NF-κB/IMD pathway by PGRP-LF is crucial to ensure proper induction of apoptosis and consequently normal fly development. These results highlight that IMD pathway regulation is controlled independently in different tissues, probably reflecting the different roles of this signaling cascade in both developmental and immune processes

Oligopeptide Transporters of the SLC15 Family Are Dispensable for Peptidoglycan Sensing and Transport in <b><i>Drosophila</i></b>

International audiencePeptidoglycan (PGN) detection by PGN recognition proteins (PGRP) is the main trigger of the antibacterial immune response in Drosophila. Depending on the type of immune cell, PGN can be sensed either at the cell membrane by PGRP-LC or inside the cell by PGRP-LE, which plays a role similar to that of Nod2 in mammals. Previous work, mainly in cell cultures, has shown that oligopeptide transporters of the SLC15 family are essential for the delivery of PGN for Nod2 detection inside of the cells, and that this function might be conserved in flies. By generating and analyzing the immune phenotypes of loss-of-function mutations in 3 SLC15 Drosophila family members, we tested their role in mediating PGRP-LE-dependent PGN activation. Our results show that Yin, CG2930, and CG9444 are required neither for PGRP-LE activation by PGN nor for PGN transport from the gut lumen to the insect blood. These data show that, while intracellular PGN detection is an essential step of the antibacterial response in both insects and mammals, the types of PGN transporters and sensors are different in these animals

Five new Camillea (Xylariales) species described from French Guiana

Abstract Background The genus Camillea was created in 1849 from collections made in French Guiana with eight species included. Numerous species assigned to Camillea were subsequently discovered, especially in the forests of the Amazon basin, but new discoveries have not been reported from French Guiana since 1849. Recent fieldwork in French Guiana has begun to fill this gap by identifying five new species, most of which were collected in the vicinity of Saül village. Results Based on macro- and micromorphological study of their stromata, including SEM images of ascospore wall ornamentation, five new species were recognized, including C. cribellum, C. heterostomoides, C. nitida, C. rogersii and C. saulensis. Cultures could be obtained for C. heterostomoides and C. rogersii, and ITS and LSU sequences were obtained for all of the five new species. Camillea heterostoma and its variety microspora were shown to be conspecific. Provisional molecular phylogenetic analyses support the possible reinstatement of Hypoxylon melanaspis, currently regarded as merely an applanate form of C. leprieurii. Conclusion The current study is based on a relatively limited fieldwork in its duration and sampling area but was able to substantially increase the number of Camillea species known from French Guiana. This augurs an exceptional and still unknown diversity of the genus in this area and by extension in the adjacent neotropical forests

PGRP-LF is mostly expressed in ectodermal derivatives.

<p>(A) <i>PGRP-LF</i>^<i>Gal4</i>, <i>UAS-nlsGFP</i> larvae showing GFP expression in salivary glands, foregut, hindgut and cuticle and to a lesser extend in fat body. <i>UAS-nlsGFP</i> larvae in a wild-type genetic background is shown as a negative control. (B) Relative <i>PGRP-LF mRNA expression</i> in third instar larvae dissected tissues. mRNA level in whole larvae was set to 100 and values obtained with dissected tissues were expressed as a fold of this value. For (B) histograms correspond to the mean value ± SD of three independent experiments. Values indicated by symbols (*) are statistically significant (t-test, p < 0.05). ns: not significantly different.</p

Cytosolic and Secreted Peptidoglycan-Degrading Enzymes in Drosophila Respectively Control Local and Systemic Immune Responses to Microbiota

International audienc

AMP expression in infected <i>PGRP-LF</i> mutants.

<p>(A) Overexpression of <i>AttacinD</i> and <i>Diptericin</i> mRNAs in <i>PGRP-LF</i> mutant larvae (either <i>PGRP-LF</i>^<i>KO</i> or <i>PGRP-LF</i>^<i>KO</i><i>/Df(3L)BSC113</i>) requires a functional PGRP-LC/IMD cascade. Inactivation of <i>IMD</i>, <i>Dredd</i>, <i>Diap2</i> and <i>Relish</i>, but not <i>dMyd88</i> or <i>PGRP-LE</i>, completely suppresses both <i>AttacinD</i> and <i>Diptericin</i> ectopic expression in <i>PGRP-LF</i> mutants. Expression of <i>UAS-PGRP-LF</i> under the control of <i>PGRP-LF</i>^{<i>Gal4strong</i>} suppresses the ectopic expression of AMPs observed in <i>PGRP-LF</i> mutants (B) Ectopic activation of AMP is not detected in mutants for other IMD pathway negative regulators such as <i>Pirk</i> or <i>PGRP-LB</i>. (C) IMD pathway activation, monitored by <i>Diptericin</i> expression, 5h after septic infection with <i>Ecc</i>. Although <i>Diptericin</i> is constitutively expressed at higher levels in uninfected <i>PGRP-LF</i> mutants (<i>PGRP-LF</i>^<i>KO</i><i>/Df(3L)BSC113</i>) than in wild-type, <i>Diptericin</i> mRNA levels are similar in fat body of wild-type and <i>PGRP-LF</i> mutant flies infected by septic injury. (D) IMD pathway activation, monitored by <i>Diptericin</i> expression, 24h after <i>Ecc</i> oral infection. While PGRP-LF inactivation does not modify IMD pathway inducibility in the midgut of <i>Ecc</i> orally infected flies, it does so in the fat body. For (A), (B), (C) and (D) mRNA level in controls was set to 1, and values obtained with indicated genotypes were expressed as a fold of this value. For (A) (B) (C) and (D) histograms correspond to the mean value ± SD of three independent experiments. Values indicated by symbols (*) are statistically significant (t-test, p < 0.05). ns: not significantly different.</p