Climate Records,Isotopes, and C:N Stoichiometry Reveal Carbon and Nitrogen Flux Dynamics Differ Between Functional Groups of Ectomycorrhizal Fungi

Ecosystems - A major functional division in ectomycorrhizal fungi is between taxa with hydrophobic ectomycorrhizae (strong proteolytic capabilities, deep nitrogen (N) acquisition, and extensive...     

Mycological records from ISAM 9, Kevo,Finland

ISAM 9 (International Symposium of Arctic-Alpine Mycology) was held in August 2012?at the Kevo Lapland Research Station in Utsjoki in northernmost Finnish Lapland. In addition to Utsjoki, some excursions were made in Finnmark, the northernmost part of Norway. Kevo station lies in the subarctic zone characterized by mountain birch (Betula pubescens var. czerepanovii), but the fells reach the arctic tundra zone. Áilegas fells at Utsjoki village and at Nuvvus lie on acid ground as does Skalluvaara, and all are under influence of reindeer grazing. The Gistuskaidi fell is highest and is characterized by the presence of more basic rocks; the vegetation also reflects some amount of maritime influence. The places visited on the Norwegian side belong to the Nesseby commune at the sea shore and Tana commune on the shore of the Tana River and along the road to Båtsfjord where the tundra is maritime and mossy with calcareous spots. In all 123 taxa were found during the excursions, some of them not determined at species level. The reported fungal taxa belong to the Basidiomycota (115 taxa), Ascomycota (7 taxa), and Mycetozoa (1 taxon).     

Northern species of earth tongue genus Thuemenidium revisited, considering morphology, ecology and molecular phylogeny

Thuemenidium is a small earth tongue genus with three recognized white-spored species. Within Thuemenidium, T. atropurpureum and T. arenarium have been reported only from the northern hemisphere while T. berteroi is known solely in the southern hemisphere. We reviewed the ecology, examined the morphology and inferred the systematic positions of northern species of Thuemenidium from LSU-rDNA gene phylogeny of 48 taxa in Pezizomycotina including recent collections. Our results suggest that Thuemenidium in its current sense is polyphyletic and that T. atropurpureum, closely related to Microglossum and Leotia species, is a member of Leotiaceae (Helotiales, Leotiomycetes). Our phylogeny placed the other northern species, T. arenarium, in Geoglossaceae (Geoglossales, Geoglossomycetes), retaining genus Thuemenidium, pending further investigation.     

Radiocarbon evidence for the mining of organic nitrogen from soil by mycorrhizal fungi

Organic nitrogen use by mycorrhizal fungi and associated plants could fuel productivity in nitrogen-limited systems. To test whether fungi assimilated soil-derived organic nitrogen, we compared the ¹⁴C signal (expressed as Δ¹⁴C) from 1950s to 1960s thermonuclear testing in protein and structural carbon of ectomycorrhizal fungi. As expected, structural carbon had Δ¹⁴C similar to recent photosynthesis; however, protein Δ¹⁴C was either higher or lower than structural carbon depending on the fungal taxa. This suggests that some protein carbon derived from uptake of organic nitrogen with different Δ¹⁴C signals. Specimens from two taxa (Lactarius and Russula) adapted to taking up soluble nutrients had protein higher than structural carbon in Δ¹⁴C, indicating uptake of young, post-bomb organic nitrogen, whereas two taxa (Cortinarius and Leccinum) adapted to using insoluble, complex organic nutrients had protein lower than structural carbon in Δ¹⁴C, indicating uptake of old, pre-bomb organic nitrogen. Tuber, a genus common in mineral soil, was also consistently lower in Δ¹⁴C for protein than for structural carbon, with an estimated 10 % of protein carbon originating from old, deep organic nitrogen for this taxon. Our results indicate that radiocarbon can provide evidence of organic nitrogen use in ectomycorrhizal fungi and reflects the exploration depth of different taxa.