Project description:Under steady state conditions, the immune system is poised to sense and respond to the microbiota. As such, immunity to the microbiota, including T cell responses, is expected to precede any inflammatory trigger. How this pool of preformed microbiota-specific T cells contributes to tissue pathologies remains unclear. Here, using an experimental model of psoriasis, we show that recall responses to commensal skin fungi can significantly aggravate tissue inflammation. Enhanced pathology caused by fungi pre-exposure depends on Th17 responses and neutrophil extracellular traps and recapitulates features of the transcriptional landscape of human lesional psoriatic skin. Together, our results propose that recall responses directed to skin fungi can directly promote skin inflammation and that exploration of tissue inflammation should be assessed in the context of recall responses to the microbiota.
Project description:The recent release of a large number of genomes from ectomycorrhizal, orchid mycorrhizal and root endophytic fungi have provided deep insight into fungal lifestyle-associated genomic adaptation. Comparative analyses of symbiotic fungal taxa showed that similar outcomes of interactions in distant related root symbioses are examples of convergent evolution. The order Sebacinales represents a sister group to the Agaricomycetes (Basidiomycota) that is comprised of ectomycorrhizal, ericoid-, orchid- mycorrhizal, root endophytic fungi and saprotrophs (Oberwinkler et al., 2013). Sebacinoid taxa are widely distributed from arctic to temperate to tropical ecosystems and are among the most common and species-rich groups of ECM, OM and endophytic fungi (Tedersoo et al., 2012, Tedersoo et al., 2010, Oberwinkler et al., 2013). The root endophyte Piriformospora indica and the orchid mycorrhizal fungus S. vermifera (MAFF 305830) are non-obligate root symbionts which were shown to be able to interact with many different experimental hosts, including the non-mycorrhizal plant Arabidopsis thaliana. These two fungi display similar colonization strategies in barley and in Arabidopsis and the ability to establish beneficial interactions with different hosts (Deshmukh et al., 2006). Colonization of the roots by P. indica and S. vermifera results in enhanced seed germination and biomass production as well as increased resistance against biotic and abiotic stresses in its experimental hosts, including various members of the Brassicaceae family, barley, Nicotiana attenuata and switchgrass (Ghimire, 2011, Ghimire et al., 2009, Ghimire et al., 2011, Waller et al., 2008, Barazani et al., 2007, Deshmukh et al., 2006). Microarray experiments were performed to identify and characterize conserved sebacinoid genes as key determinants in the Sebacinales symbioses.
Project description:Mycotoxins are secondary metabolites which are produced by numerous fungi and pose a continuous challenge to the safety and quality of food commodities in South Africa. These toxins have toxicologically relevant effects on humans and animals that eat contaminated foods. In this study, a diagnostic DNA microarray was developed for the identification of the most common food-borne fungi, as well as the genes leading to toxin production. A total of 40 potentially mycotoxigenic fungi isolated from different food commodities, as well as the genes that are involved in the mycotoxin synthetic pathways, were analyzed. For fungal identification, oligonucleotide probes were designed by exploiting the sequence variations of the elongation factor 1-alpha (EF-1 alpha) coding regions and the internal transcribed spacer (ITS) regions of the rRNA gene cassette. For the detection of fungi able to produce mycotoxins, oligonucleotide probes directed towards genes leading to toxin production from different fungal strains were identified in data available in the public domain. The probes selected for fungal identification and the probes specific for toxin producing genes were spotted onto microarray slides. The diagnostic microarray developed can be used to identify single pure strains or cultures of potentially mycotoxigenic fungi as well as genes leading to toxin production in both laboratory samples and maize-derived foods offering an interesting potential for microbiological laboratories. Keywords: Development of a diagnostic microarray for the identification of potentially mycotoxigenic fungi as well as genes leading to toxin production, 40 food-borne fungi, mycotoxins
Project description:We analyzed oxidized 5-methylcytosine derivatives 5-hydroxymethylcytosine, 5-formylcytosine and 5-carboxylcytosine in nucleic acids of multicellular fungi Laccaria bicolor and Coprinopsis cinerea which have been used as models to study DNA methylation, developmental processes and symbiotic interactions. All three cytosine derivatives were detected in the genomes of both fungi, and importantly, we discovered 5carC in the RNA fractions, potentially including large non-coding, messenger RNAs and small RNA molecules, indicating gene regulatory functions of 5carC.
Project description:Powdery mildew (PM) is one of the most important and widespread plant diseases caused by obligate biotrophic Ascomycete fungi in the order of Erysiphales. Monocot PM fungi such as Blumeria graminis f.sp. hordei (Bgh) infectious on barley and B. graminis f.sp. tritici (Bgt) infectious on wheat exhibit high-level of host-specialization. By contrast, many dicot PM fungi display rather broad host ranges. To understand why different PM fungi adopt distinct modes of host-adaption, we sequenced the genomes of four dicot PM strains belonging to Golovinomyces cichoracearum (GcC1, GcM1, GcM3) or Oidium neolycopersici (OnM2) and conducted comparative sequence analyses. PM fungi have highly repetitive genomes that are difficult to perform gene prediction. By combing RNA-seq expression evidence with ab initio gene prediction, we successfully improved the number of predicted genes from 4000 to 6000. By comparing the transcriptional profiling from haustoria with mycelia in OnM2 and GcM3, we found that 86%-96% of the predicted genes are expressed in mycelia and/or haustoria, indicating an efficient expression system of PM fungi. Besides, our results showed that gene regulation mechanisms in haustorial cells maybe under gone a much higher level of diversification between OnM2 and GcM3, since they share only a small proportion (21%) of genes up-regulated in huastoria cells. Notably, a higher proportion of candidate effector genes are selectively up-regulated in haustorial cells, agreeing with their function in suppressing host defense and facilitating nutrient uptake.
Project description:Target of rapamycin (TOR), discovered in Saccharomyces cerevisiae, is a highly conserved serine/threonine kinase acting as a regulatory hub between the cell and its environment. Like mammals, in fungi, the TOR complex 1 (TORC1) pathway is essential for coordinating cell growth in response to nutrient availability. The activation of TORC1 is similar in yeast and mammals, while its inhibition is more complex in mammals. This divergence of TORC1 regulation opens the question of how common are the yeast and mammalian variants in the fungal kingdom. In this work, we trace the evolutionary history of TORC1 components throughout the fungal kingdom. Our findings show that these fungi contain the mammalian-specific KICSTOR complex for TORC1 inhibition. They also possess orthologs of serine, arginine and methionine sensors of TORC1 pathway that orchestrate the response to nutrient starvation in mammals. The Rheb-TSC mediated activation of mammalian TORC1 that was lost in Saccharomycotina was also conserved in non-Dikarya. These findings indicate that the TORC1 pathway in non-Dikarya fungi resembles mammalian TORC1. Saccharomycotina lost many of the inhibitory components and evolved alternate regulatory mechanisms. Furthermore, our work highlights the limitations of using S. cerevisiae as a fungal model while putting forward other fungi as possible research models.
Project description:Mycotoxins are secondary metabolites which are produced by numerous fungi and pose a continuous challenge to the safety and quality of food commodities in South Africa. These toxins have toxicologically relevant effects on humans and animals that eat contaminated foods. In this study, a diagnostic DNA microarray was developed for the identification of the most common food-borne fungi, as well as the genes leading to toxin production. A total of 40 potentially mycotoxigenic fungi isolated from different food commodities, as well as the genes that are involved in the mycotoxin synthetic pathways, were analyzed. For fungal identification, oligonucleotide probes were designed by exploiting the sequence variations of the elongation factor 1-alpha (EF-1 α) coding regions and the internal transcribed spacer (ITS) regions of the rRNA gene cassette. For the detection of fungi able to produce mycotoxins, oligonucleotides directed towards genes leading to toxin production from different fungal strains were identified in data available in the public domain. The oligonucleotides selected for fungal identification and the oligonucleotides specific for toxin producing genes were spotted onto microarray slides. The diagnostic microarray developed can be used to identify potentially mycotoxigenic fungi as well as genes leading to toxin production in both laboratory and food samples offering an interesting potential for microbiological laboratories. Keywords: Development of a diagnostic microarray for the identification of potentially mycotoxigenic fungi as well as genes leading to toxin production, 40 food-borne fungi, mycotoxins Development of a diagnostic array for the identification of food-borne fungi and their potential mycotoxin-producing genes. Oligonucleotide probes to be printed onto the array were designed by exploiting the sequence variations of the elongation factor 1-alpha (EF-1 α) coding regions and the internal transcribed spacer (ITS) regions of the rRNA gene cassette. For the detection of fungi able to produce mycotoxins, oligonucleotides directed towards genes leading to toxin production from different fungal strains were identified in data available in the public domain. Analysis was performed with 40 fungal cultures were obtained from the Agricultural Research Council culture collection (ARC), Pretoria, South Africa.an in-house spotted oligonucleotide microarray. The identity of each fungus was confirmed by standard laboratory procedures. For DNA isolation, the fungal strains were grown on 1.5% malt extract agar at 25°C for 1-2 weeks and total genomic fungal DNA was extracted following the DNA extraction protocol described by Raeder and Broda (1985). The internal transcribed spacer oligonucleotides ITS1, ITS3 and ITS4 were used as a reference for normalization of all spot intensity data.Samples were fluorescently labelled with Cy5 dye by using a Cyâ¢Dye Post-labelling Reactive Dye Pack and wre hybridized to the oligonucleotide microarray overnight. Two biological and one technical replicate (using independent labelling reactions) was performed, each replication consisting of a reverse labelling experiment.