Endophytic fungi are integral components of plant microbiomes, contributing to host health, stress tolerance, and secondary metabolite production. While these communities have been extensively studied in several plant species, knowledge of fungal endophytes in Humulus lupulus (hop) remains limited, with previous research largely restricted to culture-dependent approaches or rhizosphere analyses. Here, we present the first metabarcoding-based assessment of fungal endophyte communities across multiple organs of wild H. lupulus plants sampled in Central Italy, using high-throughput sequencing of the ITS2 region. Our results reveal that fungal communities differed significantly in composition and diversity across plant organs, showing pronounced tissue-specificity and a limited shared core mycobiome. These findings advance our understanding of hop-associated fungal endophytes and provide a baseline for investigating their ecological roles and potential applications in sustainable agriculture and biotechnology.
Along a key life-history determining axis, I identify two fundamentally different growth strategies of mycelium-forming fungi, explaining differences in sporulation, mycelial lifespan and nutrient stoichiometry. One extreme is fast, ‘pyramid-scheme’-like, growth: an exponentially increasing number of hyphae provides the mycelium with a constant and high supply of nutrients. However, space and resources quickly become limiting for exponential growth, necessitating dispersal via spores away from short-lived mycelia. The other extreme is slow, sustainable, growth with mostly linear hyphal expansion. However, linear growth provides insufficient influx of nutrients to supply the entire colony at a constant rate, predicting that generally only the colony edge can be sustained in long-lived fungi. The identified differences between exponential and linear growth strategies are associated with relatively high and low N and P fungal stoichiometry, respectively. Next to asexual sporulation, I also propose cord formation, seen in some fairy-ring fungi, as a mechanism for local dispersal that initiates bursts of exponential growth with its accompanying N-P-biased fungal stoichiometry.
High-latitude ecosystems are experiencing rapid environmental change, yet fungal diversity in subantarctic regions remains underdescribed. Navarino Island (55 degrees S), represents a globally significant yet understudied landscape for describing fungal communities. In this study, we characterized soil fungal communities along an altitudinal gradient using ITS metabarcoding. Sequencing was carried out using Illumina and Oxford Nanopore technologies (ONT), to evaluate their complementarity for fungal community characterization. Bioinformatic processing was performed with LotuS2, adjusting the pipeline for ONT long reads. Community composition, alpha- and beta-diversity patterns, and functional guild composition was evaluated for both technologies. A total of 2858 OTUs were recovered by Illumina, while ONT recovered between 353 and 1179, depending on the processing approach. Illumina achieved better taxonomic resolution and detection of compositional differences, while ONT output was highly influenced by the pipeline. Despite methodological differences, both technologies detected a consistent ecological pattern of increasing ectomycorrhizal fungi abundance with altitude, consistent with previous descriptions, also recovering shared taxa across all fungal guilds. Furthermore, ONT detected some unique taxa, suggesting complementary potential for fungal community characterization. This study provides a baseline for understanding soil fungal diversity in the subantarctic ecoregion and contributes essential data for future monitoring of biodiversity responses to climate change.
Airborne fungal DNA is used as a tool to estimate fungal diversity inhabiting various ecosystem substrates. Understanding the spatial dynamics of airborne DNA assemblages is necessary to link airborne DNA assemblages with local fungal communities. In this study, we aimed to clarify how vegetation, which influences local fungal communities, and spatial distance shape the spatial structure of airborne DNA assemblages. In a continuously forested landscape of approximately 10 km, we selected ten stands across three vegetation types and monitored the airborne DNA assemblages in these stands for over five months. Although vegetation significantly influenced the DNA assemblages, temporal variation exceeded spatial variation. Little overlap in the assemblages was observed, even between the closest stands that were approximately 20 m apart, implying a limited dispersal even at this distance. By focusing on a heterogeneous environment, we demonstrated that airborne DNA assemblages show dynamics at a smaller spatial scale than previously recognized.
Ascension Island is a remote oceanic island that was a volcanic desert prior to human colonisation. In the 19th century, an artificial cloud forest was established by a military garrison to improve the scarce water supply. Using ITS metabarcoding of topsoil environmental DNA, we compared the fungal communities of the desert and the Green Mountain cloud forest. Forest soils had higher total nitrogen and carbon, and lower pH than desert soils. Fungal richness was higher in forest soils and ordination analysis revealed distinct fungal communities in each habitat. Both habitats contained a high percentage of unclassified fungal OTUs, implying the presence of native/endemic fungal flora, with a shift from Ascomycota in the desert to Asco-Basidiomycota in the forest. Indicator species analysis revealed habitat- and vegetation-specific fungal taxa, and the presence of cosmopolitan fungi in forest and unknown fungi in the desert soils, suggesting reshaping of fungal communities due to the afforestation.
