Two novel Pleosporales species isolated from the bark of Acer saccharum.

During a survey of culturable microfungi from the bark of sugar maple (Acer saccharum), Atrocalyx glutinosus and Nigrograna rubescens, two novel species of Pleosporales (Dothideomycetes) were isolated from several locations in eastern Ontario, Canada. Formal species descriptions are presented based on unique colony phenotypes and micromorphological characteristics and supported using multi-locus molecular phylogenetic comparisons with similar species. Both A. glutinosus and N. rubescens produce pycnidial asexual morphs in culture. As their names imply, under specific culture conditions, A. glutinosus excretes large amounts of the glutinous polysaccharide pullulan and N. rubescens produces a dark red naphthoquinone pigment that diffuses in the culture medium. Citation: Mack JN, Sproule A, Shields SW, Seifert KA, Smith M, Overy DP (2024). Two novel Pleosporales species isolated from the bark of Acer saccharum . Fungal Systematics and Evolution 13: 1-14. doi: 10.3114/fuse.2024.13.01.

Exploring within-ecodistrict lake organic matter variability and identifying possible environmental contaminant biomarkers using sedimentomics.

Sedimentomics methods offer insight into the physiological parameters that influence freshwater sediment organic matter (sedOM). To date, most sedimentomics studies characterized variations across large spatial and environmental gradients; here we examine whether sedimentomics methods capture subtle sedOM variations within a relatively homogeneous study area in southwestern Nova Scotia, Canada. Additionally, we explore the lake sedimentome for candidate biomarkers related to ongoing carnivorous animal farming in the region. Sediment cores were recovered from seven lakes across a trophic (oligo- to eu- trophic) and anthropogenic land use gradient (carnivorous animal farming in catchment, downstream of farming, no farming nearby). Subsamples that dated prior to 1910 (pre-carnivorous animal farming) and later than 2010 (during carnivorous animal farming) were analyzed using UHPLC-HRMS in both negative (ESI-) and positive (ESI+) electrospray ionization modes. Cluster analysis (k-means) showed replicate samples from a given lake clustered distinctly from one another in both ESI modes, indicating sedOM captured subtle variations between lake systems. PCA combined with multiple linear regression indicated carnivorous animal farming and OM source explained most of the observed variation in lake sedOM. Principal component analysis (PCA) and Partial Least Squares Discriminant Analysis (PLS-DA) of ESI- and ESI+ data sets identified 103 unique candidate biomarkers. Ten strong candidate biomarkers were identified using graphical methods; more research is required for biomarker verification and molecular characterization. Our results indicate sedimentomics could be used in environmentally homogeneous areas, offering insight into the controls of sedOM cycling. Additionally, we identified prospective biomarkers related to carnivorous animal farming that could be used to understand relative contributions of farming to ongoing eutrophication issues in southwestern Nova Scotia.