Fungal Ecology最新文献

Fungi in the phylum Cryptomycota have been recovered in numerous environmental DNA (eDNA) surveys but are only known from five described genera of intracellular parasites. These fungi are common in aquatic and soil habitats, but little is known about their relative diversity and specificity among particular habitats. We surveyed Cryptomycota from 80 eDNA samples including freshwater, soil, and marine habitats using Cryptomycota-preferential primers coupled with long-amplicon PacBio sequencing (1.2 kb of the 18S rRNA gene region). We found that freshwater samples were the most diverse, comprising 175 operational taxonomic units (OTUs) of Cryptomycota and also showed a high abundance of the related algae-parasitic group Aphelidiomycota, while marine samples were the least diverse with 25 OTUs. The composition of Cryptomycota communities was influenced by habitat, with freshwater and soil showing statistically distinct communities. Phylogenetic analyses showed that the present survey recovered most previously sampled major clades of Cryptomycota, but most (61%) OTUs were novel to this study, indicative of an extensive diversity of the group that remains largely uncharacterized.

The grapevine trunk diseases Eutypa and Botryosphaeria dieback, caused by fungal species that infect pruning wounds, are a threat to vineyard longevity worldwide. This study evaluated the susceptibility of grapevine pruning wounds in three climatic regions of Australia. In field trials, wounds were made early, mid- and late winter, and inoculated with spores of Eutypa lata or Diplodia seriata at various times, from 1 to 112 days after pruning. For both pathogens, wounds were highly susceptible immediately after pruning, followed by a rapid decrease in susceptibility over the next 14 days in McLaren Vale and Adelaide Hills, South Australia, whereas the period of susceptibility was longer in Big Rivers, New South Wales, where high natural disease pressure of D. seriata confounded results. In the Adelaide Hills, delaying pruning to late winter may reduce the risk of infection by E. lata. A detached cane assay confirmed that the duration of susceptibility of six commonly grown cultivars to E. lata infection was similar.

Serpula lacrymans causes structural damage in timber via cellulose and hemicellulose decomposition. Serpula lacrymans shares its habitat with bacteria and fungi, interactions that often result in stress and changed behaviour of the partners. A typical response to environmental stress is the production of bioactive metabolites and pigments. The diversity and function of these metabolites in inter- and intra-kingdom interactions, is largely elusive. Using dual culture approaches and secondary metabolite fingerprinting with high performance thin layer chromatography (HPTLC) it was demonstrated that stress induces an unspecific vs. Similar metabolite patterns were identified when S. lacrymans was co-cultured with different bacteria and mycoparasitic fungi (Trichoderma spp.). By analysing the metabolites produced along the gradient from the contact zone to more remote parts of the mycelium, we show a systemic reaction of S. lacrymans and that direct contact with other microbes is not a necessity to induce secondary metabolites.

Temperate forests across the globe are migrating as a result of global warming, but little is known about how changes in climate and host geographic distributions will affect the obligate symbionts of these forests. Analysis of past events can provide insight into how these symbionts have responded to previous climatic changes and inform predictions for contemporary and future climate change events. The Madrean Sky Islands Archipelago (MSIA) comprises mountain “islands” whose Pine-Oak forests appear in stark contrast to the surrounding “sea” of Sonoran Desert vegetation. The archipelago formed due to a post-Pleistocene warming climate that resulted in the expansion of the Sonoran Desert and migration of forests to fragmented, higher elevation areas. Rhizopogon (Boletales) consists of obligate ectomycorrhizal (EcM) symbionts that form truffle sporocarps and associate exclusively with Pinaceae. As such, the MSIA-Rhizopogon system represents a natural experiment of how fungal symbionts responded to climatic change and host migration. Rhizopogon was sampled from nine islands at two sites (one Pinus site and one Pseudotsuga site) per island, and diversity was characterized using the ITS rRNA gene determined from both sporocarps and bioassay-based EcM root tips derived from soil samples collected at each site. We described the biodiversity of Rhizopogon within and among sky islands of the MSIA, and tested whether symbiont species richness and community structure were determined by host association, island identity, geographic distance, or some interaction among these factors. Twenty-five OTUs at 99% similarity in the genus Rhizopogon were identified across nine sky islands with a range of 5–15 OTUs per island. While differential host association with Pinus and Pseudotsuga was a significant driver of community composition, our results supported an even stronger island effect. Furthermore, Rhizopogon communities associated with Pinus forest sites were characterized by random phylogenetic structures across sky islands and are not structured by geographic distance. Our results supported a strong isolation effect that involved historical habitat fragmentation of sky islands in response to past climate changes, and that both host association and stochastic processes, e.g., ecological drift, played a role in shaping Rhizopogon communities of the MSIA.

Vegetation indices are corner stones in vegetation monitoring. However, previous field studies on lichens and NDVI have been based on passive sensors. Active handheld sensors, with their own light sources, enables high-precision monitoring under variable ambient conditions. We investigated the use of handheld sensor NDVI for monitoring pale lichen cover across three study sites from boreal heathlands to High Arctic tundra (62–79 °N), and compared it with Sentinel-2 satellite NDVI. NDVI decreased with increasing cover of pale lichens but the correlation between active and satellite NDVI varied between areas. NDVI values declined with lichen cover and ranged from 0.4–0.18 when lichen cover was above 40%. Active ground measurements of NDVI explained 81% of the variation in the satellite NDVI values in Svalbard (High Arctic), while the relationships were lower (∼30% explained variation) in boreal regions (Troms-Finnmark and Røros). We show that active sensors are feasible for extracting information from lichen-dominated vegetation.

Plants are colonized by fungal endophytes. In this study we tested the hypothesis that endophyte communities in mountain plants changes along the elevation gradient. We identified fungal endophytes in aboveground parts and seeds of five plant species at altitudes of 1000–1750 m in the Tatra National Park. Endophytes isolated from them were grouped into morphotypes on the basis of macroscopic features, such as mycelium shape and colour. Isolates representing individual morphotypes were identified using molecular markers ITS1 and ITS2. When comparing species composition, we used Bray-Curtis distance matrices, calculated on the basis of frequency of the given fungal species. We identified 16 species of fungal endophytes. Five taxa were absent from seeds in spite of their occurrence in mother plant leaves. Differences in altitude were not significantly correlated with fungal species composition observed at a given sampling site. There was also no significant correlation between the species composition of leaf and seed mycobiota. This suggests imperfect vertical transmission in the studied plant species.

Rhizosphere and endophytic microbial communities are crucial for plant fitness and affect how plants cope with abiotic stress. In this study, we provide evidence that drought stress affected alpha and beta diversity of fungal communities associated with the roots and rhizosphere of castor bean (Ricinus communis) through metabarcoding of 18S rRNA gene. Plants were cultivated in soil columns in the greenhouse at three different watering regimes, i.e., 50% water holding capacity (WHC; wet) or adjusted to 50% WHC every 2 weeks (dry) or every month (extremely dry). Ascomycota, Basidiomycota, Chytridiomycota and Fusarium dominated the soil and rhizosphere and Fusarium, Cladosporium, Mucor, Cystofilobasidium, Penicillium and Malassezia the roots. Under extremely dry conditions, root and rhizosphere taxonomic and functional alpha diversity increased compared to the wet treatment. However, the species turnover decreased in the stressed compared to the non-stressed roots, enriching specific fungal groups. Drought did not affect the association between castor bean and arbuscular mycorrhizal (AM) fungi. The phenolic content in stressed roots was significantly lower compared to wet conditions with a negative correlation between AM fungal colonization and root phenolic content.

We measured extracellular bioelectrical activities of the ectomycorrhizal basidiomycete Laccaria bicolor under field conditions to examine its response to environmental factors. Six fruit bodies of L. bicolor in a cluster, to which electrodes were attached, exhibited less electrical potentials at the beginning, probably due to the lack of precipitation for over a week. However, its electrical potential fluctuated after raining, sometimes over 100 mV. The electrical potential of the fruit bodies and its fluctuation were correlated with precipitation. Causality analysis of electrical potential after the rain showed electrical signal transport among fruit bodies, particularly between spatially close ones, with potential directionality. Our preliminary results bring a call for studies on fungal electrical potentials in a more ecological context under field conditions.

Fungal infection in sea turtle nests has become a potential threat to sea turtle embryos. We screened the hatchery nest sand, eggshells of failed eggs, and stillbirths of green turtles and hawksbills collected from hatcheries in Malacca, Pahang, Perak and Terengganu for the presence of fungi. The DNA sequence of the ITS region of the three highest occurring isolated fungi confirmed that these species were Pseudallescheria ellipsoidea (35.4%), Scedosporium aurantiacum (27.2%), and Fusarium solani (22.0%). Morphological characteristics of these fungi were recorded. Although the total fungi abundance had no significant effect on hatching success (p > 0.05), the abundance of P. ellipsoidea significantly increased mortality in the nests (r = 0.70, p < 0.05). Future research should focus on understanding the biological aspects of this species to establish a more effective mitigation technique for the prevention of fungal infection of sea turtle eggs and hatchery employees.

Wood decay fungi are considered to be dispersed by wind, but dispersal by animals may also be important, and more so in managed forests where dead wood is scarce. We investigated whether beetles could disperse spores of the keystone species Fomitopsis pinicola. Beetles were collected on sporocarps and newly felled spruce logs, a favourable habitat for spore deposition. Viable spores (and successful germination) of F. pinicola were detected by dikaryotization of monokaryotic bait mycelium from beetle samples. Viable spores were on the exoskeleton and in the faeces of all beetles collected from sporulating sporocarps. On fresh spruce logs, nine beetle species transported viable spores, of which several bore into the bark. Our results demonstrate that beetles can provide directed dispersal of wood decay fungi. Potentially, it could contribute to a higher persistence of some species in fragmented forests where spore deposition by wind on dead wood is less likely.