Project description:Fungal pathogens are emerging threats to global health and the rise of incidence is associated with climate change and increased geographical distribution; factors also influencing host susceptibility to infection. Accurate detection and diagnosis of fungal infections is paramount to align options for rapid and effective therapeutic treatments. For improved diagnostics, the discovery and development of biomarkers presents a promising avenue; however, this approach requires a priori knowledge of markers of infection. To uncover putative novel biomarkers of disease, profiling of the host immune response and pathogen virulence factor production is indispensable. In this study, we use mass spectrometry-based proteomics to resolve the temporal and spatial proteomes of Cryptococcus neoformans infection of the spleen following a murine model of infection. Dual perspective proteome profiling defines global remodeling of the host over a time course of infection, confirming activation of immune associated proteins connected to fungal infections. Conversely, pathogen proteomes detect well-characterized C. neoformans virulence determinants, along with novel mapped patterns of pathogenesis during progression of disease. Together, our systematic approach confirms immune protection against fungal pathogens and explores the discovery of putative biomarkers from complementary biological systems for monitoring the presence and progression of cryptococcal disease.
Project description:Understanding biological diversity and distribution patterns at multiple spatial scales is a central issue in ecology. Here, we investigated the biogeographical patterns of functional genes in soil microbes from 24 arctic heath sites using GeoChip-based metagenomics and principal coordinates of neighbour matrices (PCNM)-based analysis. Functional gene richness varied considerably among sites, while the proportions of each major functional gene category were evenly distributed. Functional gene composition varied significantly at most medium and broad spatial scales, and the PCNM analyses indicated that 14-20% of the variation in total and major functional gene categories could be attributed primarily to relatively broad-scale spatial effects that were consistent with broad-scale variation in soil pH and total nitrogen. The combination of variance partitioning and multi-scales analysis indicated that spatial distance effects contributed 12% to variation in functional gene composition,whereas environmental factors contributed only 3%. This relatively strong influence of spatial as compared to environmental variation in determining functional gene distributions contrasts sharply with typical microbial phylotype/species-based biogeographical patterns in the Arctic and elsewhere. Our results suggest that the distributions of soil functional genes cannot be predicted from phylogenetic distributions because spatial factors associated with historical contingencies are relatively important determinants of their biogeography.
Project description:Dynamic regulation of silencing histone marks, specifically H3K9me3 and H3K27me3, provide effector gene expression plasticity, which enables adaptative responses to environmental fluctuations in plant fungal pathogens. It remains an unanswered question whether the epigenetic regulatory mechanisms governing gene expression during infection stages in Phytophthora are the same as in fungal pathogens. We performed chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq) of three histone modifications, H3K4me3, H3K36me3, and H3K27me3 in P. sojae and P. infestans, encompassing both the mycelium stage, and infection stages (12h post-inoculation (hpi), and 24hpi in soybean, as well as 3dpi in potato respectively).Integrative analysis of ChIP-seq and RNA-seq data of mycelium and infection stages was performed.Overall, our work provides a comprehensive and detailed view of distinctive chromatin dynamic patterns during the infection stages of Phytophthora.
Project description:A first line of defense against pathogen infections is the recognition of pathogen-associated molecular patterns (PAMPs), leading to PAMP-triggered immunity (PTI). MicroRNAs (miRNAs) are primarily known as central regulators of plant development, but a few have also been connected to immunity. We have found that several fungal pathogens lead to a reduction in miR396 levels, suggesting that miR396 are negative regulators of downstream defense responses. In agreement with such as scenario, constitutive attenuation of miR396 activity enhances resistance to infection by fungal pathogens, while increased miR396 activity reduces pathogen resistance. We conclude that constitutive reduction of miR396 levels confer a primed state for enhanced defense reactions
Project description:Understanding the biogeographical patterns and underlying drivers of microbial functional diversity is essential for anticipating climate change impacts on ecosystem functioning worldwide. However, this matter remains scarcely addressed in freshwater ecosystems. Using the high-throughput gene array GeoChip 4.0, we show that functional gene alpha diversity and compositon differ across mountains, alpha diversity declines towards high elevations and compositional turnover increases with larger elevational distances. Both continental- and mountain-scale patterns were primarily driven by climatic variables.
2020-06-22 | GSE128826 | GEO
Project description:Biogeographical patterns in seagrass sedimentary and rhizosphere microbiomes