Project description:Predatory interactions among microbes are a major evolutionary driving force for biodiversity. The fungivorous amoeba Protostelium aurantium has a wide fungal food spectrum including major pathogenic members of the genus Candida. Phagocytic feeding by P. aurantium is highly effective with C. parapsilosis, a major pathogenic yeast. Here we show that upon ingestion by the amoeba C. parapsilosis is confronted with an oxidative burst and undergoes phagosomal lysis within minutes. On the fungal side, a functional genomic approach identified the fungal copper and redox homeostasis as primary targets of amoeba predation with the highly expressed copper exporter Crp1 and the peroxiredoxin Prx1 contributing to survival when encountering P. aurantium. The fungolytic activity was largely retained in intracellular vesicles of the amoebae. Following their isolation, the content of these vesicles induced immediate killing and lysis of C. parapsilosis. A proteomic analyses identified 56 vesicular proteins. Although fully unknown proteins were dominant, many of them could be categorized as hydrolytic enzymes presumably targeting the fungal cell wall, indicating that fungal cell wall structures are under predatory selection pressure in natural environments.
2021-12-01 | PXD023816 | Pride
Project description:Biodiversity of beneficial soil-borne fungal probiotics
Project description:A functional biodiversity microarray (EcoChip) prototype has been developed to facilitate the analysis of fungal communities in environmental samples with broad functional and phylogenetic coverage and to enable the incorporation of nucleic acid sequence data as they become available from large-scale (next generation) sequencing projects. A dual probe set (DPS) was designed to detect a) functional enzyme transcripts at conserved protein sites and b) phylogenetic barcoding transcripts at ITS regions present in precursor rRNA. Deviating from the concept of GeoChip-type microarrays, the presented EcoChip microarray phylogenetic information was obtained using a dedicated set of barcoding microarray probes, whereas functional gene expression was analyzed by conserved domain-specific probes. By unlinking these two target groups, the shortage of broad sequence information of functional enzyme-coding genes in environmental communities became less important. The novel EcoChip microarray could be successfully applied to identify specific degradation activities in environmental samples at considerably high phylogenetic resolution. Reproducible and unbiased microarray signals could be obtained with chemically labeled total RNA preparations, thus avoiding the use of enzymatic labeling steps. ITS precursor rRNA was detected for the first time in a microarray experiment, which confirms the applicability of the EcoChip concept to selectively quantify the transcriptionally active part of fungal communities at high phylogenetic resolution. In addition, the chosen microarray platform facilitates the conducting of experiments with high sample throughput in almost any molecular biology laboratory. In this study, two independent RNA samples from a pine forest soil were labelled and hybridised to a custom-made EcoChip microarray consisting of about 9000 probes targeting expressed fungals genes and about 5000 probes targeting the precursor-rRNA of different fungal lineages