A conserved fungal glycosyltransferase facilitates pathogenesis of plants by enabling hyphal growth on solid surfaces

Article Authors Metrics Comments Related Content Abstract Author summary Introduction Results and discussion Conclusions Methods Supporting information Acknowledgments References Reader Comments (0) Media Coverage (0) Figures Abstract Pathogenic fungi must extend filamentous hyphae across solid surfaces to cause diseases of plants. However, the full inventory of genes which support this is incomplete and many may be currently concealed due to their essentiality for the hyphal growth form. During a random T-DNA mutagenesis screen performed on the pleomorphic wheat (Triticum aestivum) pathogen Zymoseptoria tritici, we acquired a mutant unable to extend hyphae specifically when on solid surfaces. In contrast “yeast-like” growth, and all other growth forms, were unaffected. The inability to extend surface hyphae resulted in a complete loss of virulence on plants. The affected gene encoded a predicted type 2 glycosyltransferase (ZtGT2). Analysis of >800 genomes from taxonomically diverse fungi highlighted a generally widespread, but discontinuous, distribution of ZtGT2 orthologues, and a complete absence of any similar proteins in non-filamentous ascomycete yeasts. Deletion mutants of the ZtGT2 orthologue in the taxonomically un-related fungus Fusarium graminearum were also severely impaired in hyphal growth and non-pathogenic on wheat ears. ZtGT2 expression increased during filamentous growth and electron microscopy on deletion mutants (ΔZtGT2) suggested the protein functions to maintain the outermost surface of the fungal cell wall. Despite this, adhesion to leaf surfaces was unaffected in ΔZtGT2 mutants and global RNAseq-based gene expression profiling highlighted that surface-sensing and protein secretion was also largely unaffected. However, ΔZtGT2 mutants constitutively overexpressed several transmembrane and secreted proteins, including an important LysM-domain chitin-binding virulence effector, Zt3LysM. ZtGT2 likely functions in the synthesis of a currently unknown, potentially minor but widespread, extracellular or outer cell wall polysaccharide which plays a key role in facilitating many interactions between plants and fungi by enabling hyphal growth on solid matrices

Antiretroviral-naive and -treated HIV-1 patients can harbour more resistant viruses in CSF than in plasma

Objectives The neurological disorders in HIV-1-infected patients remain prevalent. The HIV-1 resistance in plasma and CSF was compared in patients with neurological disorders in a multicentre study. Methods Blood and CSF samples were collected at time of neurological disorders for 244 patients. The viral loads were >50 copies/mL in both compartments and bulk genotypic tests were realized. Results On 244 patients, 89 and 155 were antiretroviral (ARV) naive and ARV treated, respectively. In ARV-naive patients, detection of mutations in CSF and not in plasma were reported for the reverse transcriptase (RT) gene in 2/89 patients (2.2%) and for the protease gene in 1/89 patients (1.1%). In ARV-treated patients, 19/152 (12.5%) patients had HIV-1 mutations only in the CSF for the RT gene and 30/151 (19.8%) for the protease gene. Two mutations appeared statistically more prevalent in the CSF than in plasma: M41L (P = 0.0455) and T215Y (P = 0.0455). Conclusions In most cases, resistance mutations were present and similar in both studied compartments. However, in 3.4% of ARV-naive and 8.8% of ARV-treated patients, the virus was more resistant in CSF than in plasma. These results support the need for genotypic resistance testing when lumbar puncture is performe

A SARS-CoV-2 protein interaction map reveals targets for drug repurposing

The novel coronavirus SARS-CoV-2, the causative agent of COVID-19 respiratory disease, has infected over 2.3 million people, killed over 160,000, and caused worldwide social and economic disruption1,2. There are currently no antiviral drugs with proven clinical efficacy, nor are there vaccines for its prevention, and these efforts are hampered by limited knowledge of the molecular details of SARS-CoV-2 infection. To address this, we cloned, tagged and expressed 26 of the 29 SARS-CoV-2 proteins in human cells and identified the human proteins physically associated with each using affinity-purification mass spectrometry (AP-MS), identifying 332 high-confidence SARS-CoV-2-human protein-protein interactions (PPIs). Among these, we identify 66 druggable human proteins or host factors targeted by 69 compounds (29 FDA-approved drugs, 12 drugs in clinical trials, and 28 preclinical compounds). Screening a subset of these in multiple viral assays identified two sets of pharmacological agents that displayed antiviral activity: inhibitors of mRNA translation and predicted regulators of the Sigma1 and Sigma2 receptors. Further studies of these host factor targeting agents, including their combination with drugs that directly target viral enzymes, could lead to a therapeutic regimen to treat COVID-19

Metabolic pathway to propionate of Pectinatus frisingensis, a strictly anaerobic beer-spoilage bacterium

International audiencePectinatus frisingensis, a recently described species of anaerobic mesophilic beer-spoilage bacteria, grows by fermenting various organic compounds, and produces mainly propionate, acetate, and succinate. Although acrylate and succinate were both dismutated by dense resting-cell suspensions, propionate production proceeded through the succinate pathway: [3-13C]pyruvate consumption led to equal 13C-labeling of propionate on methyl and methylene groups. Growth on glucose or glycerol led to a similar propionate to acetate ratio, suggesting dihydroxyacetone phosphate as being a common metabolic intermediate. Diacetyl, 1,3-propanediol, and 2,3-butanediol were not growth substrates or fermentation products, but they were all dismutated by dense resting-cells suspensions to acetate and propionate. Acetoin was a minor fermentation product. The consumption of [2-13C] or [3-13C]pyruvate by dense resting-cell suspensions demonstrated the involvement of two equivalent pyruvate molecules during acetoin production. Key enzymes involved in this metabolism were measured in anoxic cell-free extracts. A tentative metabolic pathway to the main fermentation products was proposed from the above results

Effet de l'orientation des buses sur la taille et la vitesse des gouttes de sprays utilisés en viticulture

International audienceSpray drift has become an important issue in pesticide application. Vineyard spraying is particularly interesting to consider, as pesticide droplets are not directed towards the ground but rather towards the targeted crop. The aim of this study was to investigate the influence of nozzle orientation on droplet size and droplet velocity using three different nozzles (IDK, TVI, and TXA) used in vineyards. Two series of measurement were performed in order to assess the effect of the gravity on sprays. Droplet size and one-dimensional droplet velocity characteristics were measured using a phase Doppler particle analyser (PDPA). Two planes, i.e., one horizontal and one vertical, were considered. Results suggest that the nozzle orientation slightly affects the size distribution, which is shifted towards larger droplets when nozzles spray horizontally compared to vertically spray. However, droplet axial velocity distribution is shifted towards lower values. Supposing that the only droplets which can reach the crop are those with an axial velocity greater than 1 m/s and a diameter larger than 100 μm, results showed significant differences according to the nozzle and orientation. More than 98.6% of the spray volume would reach the target whatever the orientation of the IDK nozzle, 78.8% of the spray volume would reach the crop when the TVI nozzle sprays horizontally, while only 16.0% of the spray volume would reach the crop when TXA nozzle sprays horizontally. This paper offers new perspectives in the comprehension and the optimization of the deposition process into the vegetation based from droplet size and velocity profiles from horizontally oriented sprays from flat fan or hollow cone nozzles

Influence de l'écoulement concourant d'air en sprays agricoles : application aux pulvérisateurs utilisés en vigne

International audienceAgricultural hydraulic nozzles are generally classified according to mean values of spray droplet diameter, like Dv10, Dv50 (i.e. Volume Median Diameter) or Dv90 measured on vertical sprays without any air co-flow. In vineyards, some sprayers deliver sprays that are horizontally oriented, and may be surrounded by an air flow. A previous study showed that median diameter was not affected by nozzle orientation (horizontal versus vertical), but gravity effect was noticeable regarding spatial repartition of droplet diameter and velocity [1]. The objective of this study was to investigate the effects of air flow on horizontal sprays, regarding droplet diameter and droplet velocity

Contribution à l'étude des grenats mérovingiens (Basilique de Saint-Denis et autres collections du musée d'Archéologie nationale, diverses collections publiques et objets de fouilles récentes. Nouvelles analyses gemmologiques et géophysiques effectuées au Centre de Recherche et de restauration des musées de France

National audienc

Contribution à l'étude des grenats mérovingiens (Basilique de Saint-Denis et autres collections du musée d'Archéologie nationale, diverses collections publiques et objets de fouilles récentes. Nouvelles analyses gemmologiques et géophysiques effectuées au Centre de Recherche et de restauration des musées de France

National audienc

Influence des caractéristiques des sprays sur la dérive potentielle de pulvérisateurs en grandes cultures : une revue bibliographique

International audienceSpray drift is a practical consequence of agricultural spraying operation. Because of agronomical and environmental impact of this phenomenon, drift has been widely studied and large information is available. This paper consists of a literature review on the relationship between physical descriptors of agricultural sprays, air conditions and resulting drift, generally studied in wind tunnels. Basic physical factors are droplet size, droplet velocity, and physico-chemical characteristics of the sprayed product. When possible, data available in the literature are gathered to draw trends. Contradictory information can sometimes appear especially regarding droplet velocity and drift control. Main physical factors consist generally of medians such as Volume Median Diameter (VMD or Dv50) that do notthat do not always represent the heterogeneity into a spray and especially spatial distribution of particle size and velocity. Technological parameters such as nozzle height, spray angle, travel speed are then related to initial physical factors that may explain anti-drift performances by wind tunnel experiments and their contribution to driftability of sprays

Influence of nozzle type, nozzle arrangement and side wind speed on spray drift as measured in a wind tunnel

International audienceSpray drift is a great concern because of environmental consequences of agricultural prac-tices. Many studies were conducted in wind tunnel (Miller, 2011; Nuyttens, 2007; Herbst, 2003) mainly focusing on the definition of quantitative deposition on collectors at different distances or heights according to (ISO 22856, 2008). In most cases, only one nozzle posi-tioned frontally (wind direction perpendicular to the main axis of a Flat Fan spray) is tested. This study was carried out in IRSTEA wind tunnel that includes a 9 m distribution test bench. A short boom of 4 nozzles (50 cm spacing, 60 cm height) was oriented in either lateral or frontal position. The effect of wind speed (2, 4 and 7.5 m.s-1), nozzle type (including mix types) were studied. Nozzle types were FF110 02 (Albuz AXI), air injection FF (Albuz CVI) 110 02, and air injection twin jets (Albuz CVI Twin) 110 02 and were used at 2.5 bar. Differ-ent nozzle arrangements represented 18 tests in lateral position and 21 in frontal position. Deposition values every 5cm are processed with an inverse cumulative calculation. Results are expressed in terms of (i) the cumulated amount of drift (ii) drift values at 5m (minimum buffer zone width in France). Results logically showed that an increase of wind speed leads to an increase in lateral spray drift values for all modalities. Results confirmed that drift reduction classification of nozzles based on lateral or frontal measurements are not comparable (Douzals, 2012). In frontal position, the number of nozzles induced a cumulative effect on spray deposition without protective effect between collateral sprays. In lateral position, CVI and CVI Twin nozzles involved less drift amount compared to AXI nozzles. Drift values were reduced when replacing the first or the two first AXI nozzles -that are most exposed to the wind- by a CVI or CVI Twin. However, drift mitigation ratio was bet-ter for the CVI Twin compared to CVI nozzle. These results will contribute to a wider study on interactions between sprays types & position and their potential contribution to drift or drift mitigation