397 research outputs found

    Global distribution of two fungal pathogens threatening endangered sea turtles

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    This work was supported by grants of Ministerio de Ciencia e Innovación, Spain (CGL2009-10032, CGL2012-32934). J.M.S.R was supported by PhD fellowship of the CSIC (JAEPre 0901804). The Natural Environment Research Council and the Biotechnology and Biological Sciences Research Council supported P.V.W. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Thanks Machalilla National Park in Ecuador, Pacuare Nature Reserve in Costa Rica, Foundations Natura 2000 in Cape Verde and Equilibrio Azul in Ecuador, Dr. Jesus Muñoz, Dr. Ian Bell, Dr. Juan Patiño for help and technical support during samplingPeer reviewedPublisher PD

    Exploration of climate influences on the abundance of galls on red willow (Salix /aevigata) across two riparian communities in Southern California

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    In Southern California, the red willow (Sa/ix laevigata Bebb) hosts a variety of gall-inducing parasitic insects. However, little is known about the ecology of these parasites, particularly the characterization of their microclimate preferences. This study explores the relationship between microclimate and gall frequencies in S. laevigata in the Ballona Wetlands and Temescal Canyon, and gall count correlated with biotic and abiotic factors such as soil pH, soil moisture and willow density. Significantly more galls per leaf were found at Temescal Canyon than Ballona Wetlands. Although the number of galls per leaf correlated negatively with soil pH, soil moisture content and canopy openness, only site and gall location were found to significantly predict the number of galls. These results suggest that additional or interacting microclimate factors may influence gall frequencies between Temescal Canyon and the Ballona Wetlands

    An integrative approach to discovering cryptic species within the Bemisia tabaci whitefly species complex

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    Bemisia tabaci is a cryptic whitefly-species complex that includes some of the most damaging pests and plant-virus vectors of a diverse range of food and fibre crops worldwide. We combine experimental evidence of: (i) differences in reproductive compatibility, (ii) hybrid verification using a specific nuclear DNA marker and hybrid fertility confirmation and (iii) high-throughput sequencing-derived mitogenomes, to show that the “Mediterranean” (MED) B. tabaci comprises at least two distinct biological species; the globally invasive MED from the Mediterranean Basin and the “African silver-leafing” (ASL) from sub-Saharan Africa, which has no associated invasion records. We demonstrate that, contrary to its common name, the “ASL” does not induce squash silver-leafing symptoms and show that species delimitation based on the widely applied 3.5% partial mtCOI gene sequence divergence threshold produces discordant results, depending on the mtCOI region selected. Of the 292 published mtCOI sequences from MED/ASL groups, 158 (54%) are low quality and/or potential pseudogenes. We demonstrate fundamental deficiencies in delimiting cryptic B. tabaci species, based solely on partial sequences of a mitochondrial barcoding gene. We advocate an integrative approach to reveal the true species richness within cryptic species complexes, which is integral to the deployment of effective pest and disease management strategies

    Ectomycorrhizal Plant-Fungal Co-invasions as Natural Experiments for Connecting Plant and Fungal Traits to Their Ecosystem Consequences

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    Introductions and invasions by fungi, especially pathogens and mycorrhizal fungi, are widespread and potentially highly consequential for native ecosystems, but may also offer opportunities for linking microbial traits to their ecosystem functions. In particular, treating ectomycorrhizal (EM) invasions, i.e., co-invasions by EM fungi and their EM host plants, as natural experiments may offer a powerful approach for testing how microbial traits influence ecosystem functions. Forests dominated by EM symbiosis have unique biogeochemistry whereby the secretions of EM plants and fungi affect carbon (C) and nutrient cycling; moreover, particular lineages of EM fungi have unique functional traits. EM invasions may therefore alter the biogeochemistry of the native ecosystems they invade, especially nitrogen (N) and C cycling. By identifying “response traits” that favor the success of fungi in introductions and invasions (e.g., spore dispersal and germination) and their correlations with “effect traits” (e.g., nutrient-cycling enzymes) that can alter N and C cycling (and affect other coupled elemental cycles), one may be able to predict the functional consequences for ecosystems of fungal invasions using biogeochemistry models that incorporate fungal traits. Here, we review what is already known about how EM fungal community composition, traits, and ecosystem functions differ between native and exotic populations, focusing on the example of EM fungi associated with species of Pinus introduced from the Northern into the Southern Hemisphere. We develop hypotheses on how effects of introduced and invasive EM fungi may depend on interactions between soil N availability in the exotic range and EM fungal traits. We discuss how such hypotheses could be tested by utilizing Pinus introductions and invasions as a model system, especially when combined with controlled laboratory experiments. Finally, we illustrate how ecosystem modeling can be used to link fungal traits to their consequences for ecosystem N and C cycling in the context of biological invasions, and we highlight exciting avenues for future directions in understanding EM invasion.Fil: Hoeksema, Jason D.. University of Mississippi; Estados UnidosFil: Averill, Colin. No especifíca;Fil: Bhatnagar, Jennifer M.. Boston University; Estados UnidosFil: Brzostek, Edward. West Virginia University; Estados UnidosFil: Buscardo, Erika. Universidade do Brasília; BrasilFil: Chen, Ko Hsuan. University of Florida; Estados UnidosFil: Liao, Hui Ling. University of Florida; Estados UnidosFil: Nagy, Laszlo. Universidade Estadual de Campinas; BrasilFil: Policelli, Nahuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Ridgeway, Joanna. West Virginia University; Estados UnidosFil: Rojas, J. Alejandro. University of Arkansas for Medical Sciences; Estados UnidosFil: Vilgalys, Rytas. University of Duke; Estados Unido

    Analysis of lineage-specific Alu subfamilies in the genome of the olive baboon, Papio anubis

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    © 2018 The Author(s). Background: Alu elements are primate-specific retroposons that mobilize using the enzymatic machinery of L1 s. The recently completed baboon genome project found that the mobilization rate of Alu elements is higher than in the genome of any other primate studied thus far. However, the Alu subfamily structure present in and specific to baboons had not been examined yet. Results: Here we report 129 Alu subfamilies that are propagating in the genome of the olive baboon, with 127 of these subfamilies being new and specific to the baboon lineage. We analyzed 233 Alu insertions in the genome of the olive baboon using locus specific polymerase chain reaction assays, covering 113 of the 129 subfamilies. The allele frequency data from these insertions show that none of the nine groups of subfamilies are nearing fixation in the lineage. Conclusions: Many subfamilies of Alu elements are actively mobilizing throughout the baboon lineage, with most being specific to the baboon lineage

    Serpentine Soils Do Not Limit Mycorrhizal Fungal Diversity

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    Background: Physiologically stressful environments tend to host depauperate and specialized biological communities. Serpentine soils exemplify this phenomenon by imposing well-known constraints on plants; however, their effect on other organisms is still poorly understood. Methodology/Principal Findings: We used a combination of field and molecular approaches to test the hypothesis that serpentine fungal communities are species-poor and specialized. We conducted surveys of ectomycorrhizal fungal diversity from adjacent serpentine and non-serpentine sites, described fungal communities using nrDNA Internal Transcribed Spacer (ITS) fragment and sequence analyses, and compared their phylogenetic community structure. Although we detected low fungal overlap across the two habitats, we found serpentine soils to support rich fungal communities that include representatives from all major fungal lineages. We failed to detect the phylogenetic signature of endemic clades that would result from specialization and adaptive radiation within this habitat. Conclusions/Significance: Our results indicate that serpentine soils do not constitute an extreme environment for ectomycorrhizal fungi, and raise important questions about the role of symbioses in edaphic tolerance and the maintenanc

    Fungal associates of the lodgepole pine beetle, Dendroctonus murrayanae

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    Bark beetles are well known vectors of ophiostomatoid fungi including species of Ophiostoma, Grosmannia and Ceratocystis. In this study, the most common ophiostomatoid fungi associated with the lodgepole pine beetle, Dendroctonus murrayanae, were characterized. Pre-emergent and post-attack adult beetles were collected from lodgepole pines at four sites in British Columbia, Canada. Fungi were isolated from these beetles and identified using a combination of morphology and DNA sequence comparisons of five gene regions. In all four populations, Grosmannia aurea was the most common associate (74–100% of all beetles) followed closely by Ophiostoma abietinum (29–75%). Other fungi isolated, in order of their relative prevalence with individual beetles were an undescribed Leptographium sp. (0–13%), Ophiostoma ips (0–15%), Ophiostoma piliferum (0–11%), a Pesotum sp. (0–11%) and Ophiostoma floccosum (0–1%). Comparisons of the DNA sequences of Leptographium strains isolated in this study, with ex-type isolates of G. aurea, Grosmannia robusta, Leptographium longiclavatum, and Leptographium terebrantis, as well as with sequences from GenBank, revealed a novel lineage within the Grosmannia clavigera complex. This lineage included some of the D. murrayane isolates as well as several isolates from previous studies referred to as L. terebrantis. However, the monophyly of this lineage is not well supported and a more comprehensive study will be needed to resolve its taxonomic status as one or more novel taxa.National Science Foundation grant OISE-0434171 awarded to DLS, Natural Resources Canada, Canadian Forest Service Mountain Pine Beetle Initiative Grant to ALC, members of the Tree Co-operative Programme, the THRIP initiative of the Department of Trade and Industry, South Africa

    A software pipeline for processing and identification of fungal ITS sequences

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    <p>Abstract</p> <p>Background</p> <p>Fungi from environmental samples are typically identified to species level through DNA sequencing of the nuclear ribosomal internal transcribed spacer (<it>ITS</it>) region for use in BLAST-based similarity searches in the International Nucleotide Sequence Databases. These searches are time-consuming and regularly require a significant amount of manual intervention and complementary analyses. We here present software – in the form of an identification pipeline for large sets of fungal <it>ITS </it>sequences – developed to automate the BLAST process and several additional analysis steps. The performance of the pipeline was evaluated on a dataset of 350 <it>ITS </it>sequences from fungi growing as epiphytes on building material.</p> <p>Results</p> <p>The pipeline was written in Perl and uses a local installation of NCBI-BLAST for the similarity searches of the query sequences. The variable subregion <it>ITS2 </it>of the <it>ITS </it>region is extracted from the sequences and used for additional searches of higher sensitivity. Multiple alignments of each query sequence and its closest matches are computed, and query sequences sharing at least 50% of their best matches are clustered to facilitate the evaluation of hypothetically conspecific groups. The pipeline proved to speed up the processing, as well as enhance the resolution, of the evaluation dataset considerably, and the fungi were found to belong chiefly to the <it>Ascomycota</it>, with <it>Penicillium </it>and <it>Aspergillus </it>as the two most common genera. The <it>ITS2 </it>was found to indicate a different taxonomic affiliation than did the complete <it>ITS </it>region for 10% of the query sequences, though this figure is likely to vary with the taxonomic scope of the query sequences.</p> <p>Conclusion</p> <p>The present software readily assigns large sets of fungal query sequences to their respective best matches in the international sequence databases and places them in a larger biological context. The output is highly structured to be easy to process, although it still needs to be inspected and possibly corrected for the impact of the incomplete and sometimes erroneously annotated fungal entries in these databases. The open source pipeline is available for UNIX-type platforms, and updated releases of the target database are made available biweekly. The pipeline is easily modified to operate on other molecular regions and organism groups.</p
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