3,000 species and no end – species richness and community pattern of woodland macrofungi in Mecklenburg-Western Pomerania, Germany

Exploring phyllosphere fungal communities of 29 alpine meadow plant species: composition, structure, function, and implications for plant fungal diseases

The phyllosphere of plants hosts diverse fungal microbial communities. Despite the significant impact of plant fungal diseases on productivity and community ecology, the relationship between phyllosphere fungal communities and plant health in natural environments remains poorly understood. This study utilized high-throughput sequencing and field investigations to explore the composition, dynamics, and incidence of fungal diseases across 29 plant species from four functional groups (forbs, grasses, legumes, and sedges) in alpine meadow plant communities of the Qinghai-Tibetan Plateau. We identified Ascomycetes and Basidiomycetes as the predominant phyllosphere fungi. Significant differences were observed in the Shannon diversity index, β-diversity, indicator fungi, and hub fungi among the functional groups. With the exception of the sedge group, the incidence of fungal diseases in other groups was positively correlated with the proportion of pathogens in the phyllosphere fungal community. Predictive analyses revealed that Ascochyta was strongly associated with high disease incidence in grasses, Cercospora in forbs, and Podosphaera in legumes, while Calophoma was associated with low disease incidence in sedges. These findings enhance our understanding of how plant phyllosphere fungal communities assemble in natural environments and improve our ability to predict and manage foliar fungal diseases in alpine meadows.

Temporal variation of fungal diversity in a mosaic landscape in Germany

This study aims at characterizing the diversity and temporal changes of species richness and composition of fungi in an ecotone of a forest border and a meadow in the Taunus mountain range in Germany. All macroscopically visible, epigeous fungi and vascular plants were sampled monthly over three years, together with climatic variables like humidity and temperature that influence fungal diversity and composition as shown by previous studies. In this mosaic landscape, a total of 855 fungal species were collected and identified based on morphological features, the majority of which belonged to Ascomycota (51 %) and Basidiomycota (45 %). Records of fungal species and plant species (218) for this area yielded a fungus to plant species ratio of 4:1, with a plant species accumulation curve that reached saturation. The three years of monitoring, however, were not sufficient to reveal the total fungal species richness and estimation factors showed that a fungus to plant species ratio of 6:1 may be reached by further sampling efforts. The effect of climatic conditions on fungal species richness differed depending on the taxonomic and ecological group, with temporal patterns of occurrence of Basidiomycota and mycorrhizal fungi being strongly associated with temperature and humidity, whereas the other fungal groups were only weakly related to abiotic conditions. In conclusion, long-term, monthly surveys over several years yield a higher diversity of macroscopically visible fungi than standard samplings of fungi in autumn. The association of environmental variables with the occurrence of specific fungal guilds may help to improve estimators of fungal richness in temperate regions.

Spatio-Temporal Variation of Core and Satellite Arbuscular Mycorrhizal Fungus Communities in Miscanthus giganteus

Arbuscular mycorrhizal fungi (AMF) are a group of obligate plant symbionts which can promote plant nutrition. AMF communities are diverse, but the factors which control their assembly in space and time remain unclear. In this study, the contributions of geographical distance, environmental heterogeneity and time in shaping AMF communities associated with Miscanthus giganteus (a perennial grass originating from south-east Asia) were determined over a 13 months period. In particular, the community was partitioned into core (abundant and persistent taxa) and satellite (taxa with low abundance and persistence) constituents and the drivers of community assembly for each determined. β-diversity was exceptionally low across the 140 m line transects, and there was limited evidence of geographical scaling effects on the composition of the core, satellite or combined communities. However, AMF richness and community composition changed over time associated with fluctuation within both the core and satellite communities. The degree to which AMF community variation was explained by soil properties was consistently higher in the core community than the combined and satellite communities, suggesting that the satellite community had considerable stochasticity associated with it. We suggest that the partitioning of communities into their core and satellite constituents could be employed to enhance the variation explained within microbial community analyses.

Ectomycorrhizal fungal assemblages of Abies alba Mill. outside its native range in Poland

Abies alba (Mill.) is an important forest tree species, native to the mountainous regions of Europe but has been also widely introduced in the lowlands outside its native range. Like most forest tree species, A. alba forms obligate mutualisms with ectomycorrhizal (ECM) fungi. This investigation sought to examine ECM fungal communities of A. alba when the species grows 400 km north of its native range in the region of Pomerania in Poland. We surveyed for ECM fungi by sampling live roots from four mature forest stands where the A. alba component ranged from 20 to 100%. Ectomycorrhizal fungal symbionts were identified based on morphotyping and sequencing of the internal transcribed spacer (ITS) of nuclear ribosomal DNA (rDNA). Thirty-five ECM fungal taxa were distinguished on root tips of A. alba from all tested stands with 22 to 27 ECM fungal taxa in the individual stand. The diversity and similarity metrics revealed a lack of statistical differences in the structure of the ECM fungal community between stands varying in overstory tree composition. Cenococcum geophilum was the most common fungal species at all investigated A. alba stands, with an abundance of 50 to 70%. The ECM community was characterized by the lack of Abies-specific fungal symbionts and a rich and diverse suite of host-generalist mycobionts that seem to be sufficient for successful growth and development of A. alba outside of its native range.