Fungi of Forests: Examining the Diversity of Root-associated Fungi and Their Responses to Acid Deposition

Global importance of forests is difficult to overestimate, given their role in oxygen production, ecological roles in nutrient cycling and supporting numerous living species, and economic value for industry and as recreational zones. Fitness of the forest-forming trees strongly depends on microbial communities associated with tree roots. In particular, fungi impact tree fitness: mycorrhizal species provide water and nutrients for the trees in exchange for C, endophytic fungi play key roles in host defense against pathogenic organisms, and saprotrophic fungi decompose dead organic matter and facilitate nutrient cycling. In addition, pathogenic fungal species strongly affect forest fitness. Despite their importance, fungal communities associated with forest trees are largely unknown because the typical morphological assay takes into consideration a scarce portion of fungal diversity: species that produce visible fruiting bodies at relatively frequent intervals. A more accurate assessment of fungal diversity in forests has become possible with the development of next-generation sequencing, where fungal species are being identified based on the presence of their DNA in the sample. In this work, DNA-metabarcoding was utilized to assess the diversity of fungi associated with roots of forest-forming trees within the families Fagaceae and Betulaceae (Europe), and Fagaceae, and Juglandaceae (North America). The data obtained provided unprecedented insight into hidden richness of root-associated fungi, which approached 1756 OTUs (a proxy for species) in the European dataset, and 2769 – in the North American dataset. Variation in fungal community composition was largely explained by geographical location (ca. 30%). However, the effect of host specificity (ca. 9-15% of variation) was significant as well. DNA-based data revealed strong positive and negative patters in fungal co-occurrence (e.g., a positive relationship was observed between Cenococcum geophilum and species of Russulaceae), which could indicate interactions between fungal species. In addition to diversity assays, fungal responses to acid precipitation were quantified, and revealed strong declines in fungal richness and abundance, including ectomycorrhizal species. I conclude that compositional shifts in root-associated fungal communities could be particularly suitable for monitoring of forest ecosystems, given an optimal response time in fungi (not too slow as in wooded plants and not as high as in bacteria)

A Phylogenetic Analysis of Species Diversity, Specificity, and Distribution of Mycodiplosis on Rust Fungi

There are more than 7800 species of Pucciniales (rust fungi) described. Aeciospores and urediniospores of rust fungi are a food source for the larval stage of members of the fly genus Mycodiplosis, hence these could be of interest as potential biological control agents. Currently, Mycodiplosis contains 49 described species based on adult male morphology. A survey of 1,350 rust-infected plants from 44 countries was recently conducted to assess the occurrence of Mycodiplosis fly larvae across a broad spectrum of Pucciniales. Larvae were found on 261 collections from 25 countries. Statistical analyses explored the distribution of larvae in relation to host species. Five of 127 rust species in the survey data were identified as infested at a greater frequency than expected using binomial probability analysis of presence/absence. DNA was extracted from individual larvae and 28S nuclear ribosomal RNA and mitochondrial cytochrome c oxidase subunit 1 (COI) genes were amplified and sequences were concatenated for maximum likelihood analyses. Test analyses were done using identical sequence regions of 28S and COI from Bradysia species and Asteromyia species respectively, to verify the ability of individual loci to resolve species. The 206 larval specimens analyzed were resolved into approximately 33 clades, 17 of which received significant support. One clade has a global distribution in the survey. Twelve clades occurred in the United States. There are currently seven species described from the United States, the finding of 12 clades in this study represents potential additional species in the Mycodiplosis. The distribution of larvae within clades could be explained partially by geographic origin but not by rust host at any taxonomic level; thus even though there is evidence for preferential feeding by larvae on some rust species, there is no evidence of host-specificity between clades of larvae and their hosts

Robust Network Stability of Mosquitoes and Human Pathogens of Medical Importance

Background: The exact number of mosquito species relevant to human health is unknown, posing challenges in understanding the scope and breadth of vector–pathogen relationships, and how resilient mosquito vector–pathogen networks are to targeted eradication of vectors. Methods: We performed an extensive literature survey to determine the associations between mosquito species and their associated pathogens of human medical importance. For each vector–pathogen association, we then determined the strength of the associations (i.e., natural infection, lab infection, lab dissemination, lab transmission, known vector). A network analysis was used to identify relationships among all pathogens and vectors. Finally, we examined how elimination of either random or targeted species affected the extinction of pathogens. Results: We found that 88 of 3578 mosquito species (2.5%) are known vectors for 78 human disease-causing pathogens; however, an additional 243 species (6.8%) were identified as potential or likely vectors, bringing the total of all mosquitos implicated in human disease to 331 (9.3%). Network analysis revealed that known vectors and pathogens were compartmentalized, with the removal of six vectors being enough to break the network (i.e., cause a pathogen to have no vector). However, the presence of potential or likely vectors greatly increased redundancies in the network, requiring more than 41 vectors to be eliminated before breaking the network. Conclusion: Although \u3c 10% of mosquitoes are involved in transmitting pathogens that cause human disease, our findings point to inherent robustness in global mosquito vector–pathogen networks

Arbuscular Mycorrhizal Fungi Taxa Show Variable Patterns of Micro-Scale Dispersal in Prairie Restorations

Human land use disturbance is a major contributor to the loss of natural plant communities, and this is particularly true in areas used for agriculture, such as the Midwestern tallgrass prairies of the United States. Previous work has shown that arbuscular mycorrhizal fungi (AMF) additions can increase native plant survival and success in plant community restorations, but the dispersal of AMF in these systems is poorly understood. In this study, we examined the dispersal of AMF taxa inoculated into four tallgrass prairie restorations. At each site, we inoculated native plant species with greenhouse-cultured native AMF taxa or whole soil collected from a nearby unplowed prairie. We monitored AMF dispersal, AMF biomass, plant growth, and plant community composition, at different distances from inoculation. In two sites, we assessed the role of plant hosts in dispersal, by placing known AMF hosts in a “bridge” and “island” pattern on either side of the inoculation points. We found that AMF taxa differ in their dispersal ability, with some taxa spreading to 2-m in the first year and others remaining closer to the inoculation point. We also found evidence that AMF spread altered non-inoculated neighboring plant growth and community composition in certain sites. These results represent the most comprehensive attempt to date to evaluate AMF spread

FungalTraits:A user-friendly traits database of fungi and fungus-like stramenopiles

The cryptic lifestyle of most fungi necessitates molecular identification of the guild in environmental studies. Over the past decades, rapid development and affordability of molecular tools have tremendously improved insights of the fungal diversity in all ecosystems and habitats. Yet, in spite of the progress of molecular methods, knowledge about functional properties of the fungal taxa is vague and interpretation of environmental studies in an ecologically meaningful manner remains challenging. In order to facilitate functional assignments and ecological interpretation of environmental studies we introduce a user friendly traits and character database FungalTraits operating at genus and species hypothesis levels. Combining the information from previous efforts such as FUNGuild and Fun(Fun) together with involvement of expert knowledge, we reannotated 10,210 and 151 fungal and Stramenopila genera, respectively. This resulted in a stand-alone spreadsheet dataset covering 17 lifestyle related traits of fungal and Stramenopila genera, designed for rapid functional assignments of environmental studies. In order to assign the trait states to fungal species hypotheses, the scientific community of experts manually categorised and assigned available trait information to 697,413 fungal ITS sequences. On the basis of those sequences we were able to summarise trait and host information into 92,623 fungal species hypotheses at 1% dissimilarity threshold

Determining the Utility of Wildlife Underpasses in Minnesota

Wildlife underpasses have been designed into some new wide-span bridges in northern Minnesota to provide a safer alternative to over-the-road crossings. Are wildlife, particularly deer, using the underpasses? Are over-the-road crossings decreasing near bridges? For 4 months pre-construction and for 18 months post- construction (and ongoing), we used trail cameras to monitor movements under four bridges and at the forest edge along the highway at three distances from the bridges. We have observed several species of wildlife using the underpasses. We will describe whether the frequency of use of underpasses by deer is increasing. We will analyze the frequency of deer movements along the road near the bridges to determine whether it is decreasing and whether it is less than pre-construction levels

The Resource Value Of Employers In The Development Of Post High School Occupational Training As Influenced By Their Awareness Of Such Programs And Other Related Factors.

PhDEducationUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/182400/2/5902161.pd

Non-Target Effects of Methoprene and Larvicidal Surface Films On Invertebrate Predators of Mosquito Larvae

Mosquito larvicides are used across a variety of aquatic habitats, although when applied they likely affect other aquatic organisms. The removal or impairment of top insect predators via larvicides could be beneficial to mosquitoes by allowing their populations to rebound once pesticide levels dissipate. Our goal was to determine if two larvicide types, growth regulators (IGRs) and surface films (SFs), harm non-target aquatic insect communities, and if these chemicals influence the ability of predatory aquatic insects to regulate mosquitoes. We surveyed aquatic sites before and after IGR and SF-application, then compared changes in insect community structure. Evenness was lower in SF treated habitats, and when analyzing prey/controphic taxa only, evenness and diversity changed in untreated reference areas, suggesting that differences measured were due to other environmental factors, not larvicide presence. A field experiment was then conducted by exposing specific predatory aquatic insects to varying doses of IGRs and SFs and then placing them in mesocosms containing mosquito larvae. Surface films were directly lethal to adult dytiscids at recommended and high concentrations. Although we found no significant differences in mosquito emergence among all treatment levels, there was a trend of negative controls (no predator mesocosms) and SF-treated predators allowing the most mosquitoes to emerge compared to positive controls (predators not exposed to larvicides) and IGR-treated predators. Thus, these larvicides may have minimal effects on mosquito larvae predators, but the direct effects of surface films on insects that interact with the water\u27s surface require further investigation