Dominant Tree Species and Soil Type Affect the Fungal Community Structure in a Boreal Peatland Forest.

Boreal peatlands play a crucial role in global carbon cycling, acting as an important carbon reservoir. However, little information is available on how peatland microbial communities are influenced by natural variability or human-induced disturbances. In this study, we have investigated the fungal diversity and community structure of both the organic soil layer and buried wood in boreal forest soils using high-throughput sequencing of the internal transcribed spacer (ITS) region. We have also compared the fungal communities during the primary colonization of wood with those of the surrounding soils. A permutational multivariate analysis of variance (PERMANOVA) confirmed that the community composition significantly differed between soil types (P< 0.001) and tree species (P< 0.001). The distance-based linear models analysis showed that environmental variables were significantly correlated with community structure (P< 0.04). The availability of soil nutrients (Ca [P= 0.002], Fe [P= 0.003], and P [P= 0.003]) within the site was an important factor in the fungal community composition. The species richness in wood was significantly lower than in the corresponding soil (P< 0.004). The results of the molecular identification were supplemented by fruiting body surveys. Seven of the genera of Agaricomycotina identified in our surveys were among the top 20 genera observed in pyrosequencing data. Our study is the first, to our knowledge, fungal high-throughput next-generation sequencing study performed on peatlands; it further provides a baseline for the investigation of the dynamics of the fungal community in the boreal peatlands.

Estimating the Phanerozoic history of the Ascomycota lineages: combining fossil and molecular data.

The phylum Ascomycota is by far the largest group in the fungal kingdom. Ecologically important mutualistic associations such as mycorrhizae and lichens have evolved in this group, which are regarded as key innovations that supported the evolution of land plants. Only a few attempts have been made to date the origin of Ascomycota lineages by using molecular clock methods, which is primarily due to the lack of satisfactory fossil calibration data. For this reason we have evaluated all of the oldest available ascomycete fossils from amber (Albian to Miocene) and chert (Devonian and Maastrichtian). The fossils represent five major ascomycete classes (Coniocybomycetes, Dothideomycetes, Eurotiomycetes, Laboulbeniomycetes, and Lecanoromycetes). We have assembled a multi-gene data set (18SrDNA, 28SrDNA, RPB1 and RPB2) from a total of 145 taxa representing most groups of the Ascomycota and utilized fossil calibration points solely from within the ascomycetes to estimate divergence times of Ascomycota lineages with a Bayesian approach. Our results suggest an initial diversification of the Pezizomycotina in the Ordovician, followed by repeated splits of lineages throughout the Phanerozoic, and indicate that this continuous diversification was unaffected by mass extinctions. We suggest that the ecological diversity within each lineage ensured that at least some taxa of each group were able to survive global crises and rapidly recovered.

New resinicolous Chaenothecopsis species from China.

Four new resinicolous species of Chaenothecopsis are described from China: Chaenothecopsis perforata from exudate of Rhus chinensis (Anacardiaceae), C. pallida from exudate of Ailanthus altissima (Simaroubaceae), C. resinophila from exudate of Kalopanax septemlobus (Araliaceae) and C. hunanensis from resin of Pinus massoniana (Pinaceae). All the new species are compared with previously described resinicolous mycocalicioid taxa, and several new features in these species are presented. The newly described species cannot always be distinguished by any single character, but they all possess unique combinations of morphological, chemical and ecological features. Several aspects in the ecology and evolution of boreal and tropical resinicolous species are briefly discussed.

Chaenothecopsis (Mycocaliciales, Ascomycota) from exudates of endemic New Zealand Podocarpaceae.

The order Mycocaliciales (Ascomycota) comprises fungal species with diverse, often highly specialized substrate ecologies. Particularly within the genus Chaenothecopsis, many species exclusively occur on fresh and solidified resins or other exudates of vascular plants. In New Zealand, the only previously known species growing on plant exudate is Chaenothecopsisschefflerae, found on several endemic angiosperms in the family Araliaceae. Here we describe three new species; Chaenothecopsismatai Rikkinen, Beimforde, Tuovila & A.R. Schmidt, C.nodosa Beimforde, Tuovila, Rikkinen & A.R. Schmidt, and C.novae-zelandiae Rikkinen, Beimforde, Tuovila & A.R. Schmidt, all growing on exudates of endemic New Zealand conifers of the Podocarpaceae family, particularly on Prumnopitystaxifolia. Phylogenetic analyses based on ribosomal DNA regions (ITS and LSU) grouped them into a distinct, monophyletic clade. This, as well as the restricted host range, suggests that all three taxa are endemic to New Zealand. Copious insect frass between the ascomata contain ascospores or show an early stage of ascomata development, indicating that the fungi are spread by insects. The three new species represent the first evidence of Chaenothecopsis from any Podocarpaceae species and the first from any gymnosperm exudates in New Zealand.

Chaenothecopsis khayensis, a new resinicolous calicioid fungus on African mahogany.

The new species Chaenothecopsis khayensis (Ascomycota, Mycocaliciaceae) is described from Ghana, western Africa, on the resin of Khaya anthotheca and K. ivorensis. The species is distinctive in forming asci without crosiers and in possessing ascospores that are faintly longitudinally striate. Analysis of large subunit rDNA gene sequences positioned this species within a clade corresponding to the Mycocaliciales and identified its closest relative as Sphinctrina leucopoda. Chaenothecopsis khayensis occurs commonly on resin exuding from trees damaged by the larvae of the mahogany shoot borer (Hypsipyla sp.), and we discuss the possible ecological relationship between the fungus and these moths.