Filters
Long term patterns of association between MHC and helminth burdens in the bank vole support Red Queen dynamics
AbstractMajor histocompatibility complex (MHC) genes encode proteins crucial for adaptive immunity of vertebrates. Negative frequency‐dependent selection (NFDS), resulting from adaptation of parasites to common MHC types, has been hypothesized to maintain high, functionally relevant polymorphism of MHC, but demonstration of this relationship has remained elusive. In particular, differentiation of NFDS from fluctuating selection, resulting from changes in parasite communities in time and space (FS), has proved difficult in short‐term studies. Here, we used temporal data, accumulated through long‐term monitoring of helminths infecting bank voles (Myodes glareolus), to test specific predictions of NFDS on MHC class II. Data were collected in three, moderately genetically differentiated subpopulations in Poland, which were characterized by some stable spatiotemporal helminth communities but also events indicating introduction of new species and loss of others. We found a complex association between individual MHC diversity and species richness, where intermediate numbers of DRB supertypes correlated with lowest species richness, but the opposite was true for DQB supertypes—arguing against universal selection for immunogenetic optimality. We also showed that particular MHC supertypes explain a portion of the variance in prevalence and abundance of helminths, but this effect was subpopulation‐specific, which is consistent with both NFDS and FS. Finally, in line with NFDS, we found that certain helminths that have recently colonized or spread in a given subpopulation, more frequently or intensely infected voles with MHC supertypes that have been common in the recent past. Overall, our results highlight complex spatial and temporal patterns of MHC‐parasite associations, the latter being consistent with Red Queen coevolutionary dynamics.
New Species of Bark Beetles in the Fauna of Poland - New Challenges for Forest Protection?
Forestry is one of the sectors particularly affected by the threats posed by changing climatic conditions. This is reflected in the deterioration of the health status of stands due to the synergistic effect of numerous abiotic and biotic factors. Current forest health problems are due to dynamic, negative changes in the forest environment. While the amount of precipitation remains at a similar level, its distribution varies throughout the year and, in particular, the lack of soil moisture during the growing season leads to the weakening of trees, including the main forest-forming species in Poland such as Pinus sylvestris. The weakening of trees, in turn, leads to species of insect pests that were previously considered secondary becoming primary pests, such as Ips acuminatus. It is likely that weakening of trees also favours increased occurrence of parasitic plants such as Viscum album ssp. austriacum or Loranthus europaeus. Infestations of the hemiparasitic, xylem-secreting pine mistletoe are of great interest because they are spreading rapidly throughout Europe. Drought in forests is not only a long-term water shortage, but also a situation in which plant-fungal relationships are disrupted. Reduced water availability leads to a number of negative changes in the soil and the mycobiota that live there, affecting entire ecosystems. The effects of climate change and increased international trade are leading to the spread of pathogenic fungi and other harmful organisms whose range was previously restricted to the south of our continent. Unfavourable abiotic and biotic factors leading to weakening of oak stands in the western part of Poland have resulted in activation of new pests like Mediterranean oak borer. Intensification of transport and shortening of its duration, as well as climatic changes, favour the introduction of various organisms, including bark beetles (Scolytinae). In Poland, cyclic insect outbreaks are one of the most important problems in forest protection. Developing methods to monitor, prevent outbreaks and control the density of insect populations below harmful levels can be a challenge to consider. Finding an innovative system for applying insecticides to control spruce bark beetle could also be an interesting solution, where insects attracted to pheromones die after contact with the insecticide. Contact with the insecticide has a dual effect: either directly when the tree is treated, or when the bark beetle attempts to invade the tree. Opportunities for the use of biostimulants in forestry and is an attractive way to regenerate plants after negative stressors such as frost, drought or damage caused by improper use of pesticides, as well as the negative effects of diseases and pests. It acts indirectly by stimulating leaf, stem and root development and improving nutrient uptake. The effects of chemical treatments on fungal biodiversity in forests should be studied using powerful molecular tools such as NGS.
Effect of Treatment of Beech Seeds with Copper Nanoparticles on Seed Coat Mycoflora
Seeds harbor a complex fungal community, of which some members may be pathogenic. For this reason, seeds are often treated with fungicides before sowing. Plant protection is constantly looking for environmentally friendly technological solutions and nanotechnology can provide a solution that is a green and environmentally friendly alternative to fungicide treatment. The aim of this study was to conduct a quantitative and qualitative analysis of the composition of fungal communities inhabiting the seed coats of healthy and damaged European beech seeds and to assess the effect of copper nanoparticles (CuNPs) on the composition of these communities. The seeds were soaked in a solution of CuNPs at a concentration of 50 ppm for 30 min. There were four groups of seeds: control—not treated with CuNPs, seeds examined 1 day after CuNP (CuNP_1day) treatment, seeds examined 3 weeks after CuNP (CuNP_3weeks) treatment, and damaged seeds—not treated. A community analysis was conducted based on the ITS1 region using Illumina sequencing. In total, we found 70 taxa of fungi and Oomycota. The community on the control seeds numbered 38 taxa, on damaged seeds—67, on seeds treated with CuNPs after 1 day—40, and after 3 weeks—15, respectively. In terms of biological diversity and species composition, the community on damaged seeds differed significantly from that on CuNP_3weeks seeds and both of these treatments differed from the remaining two. On the damaged seeds, the dominant species were as follows: Botritis cinerea Pers., Globisporangium intermedium (de Bary) Uzuhashi, Tojo & Kakish., and Pythium dissotocum Drechsler. The communities of the other seed groups were dominated by Fusicoccum quercus Oudem. and Apiognomonia errabunda (Roberge ex Desm.) Höhn., which proved resistant to CuNPs. Taxa belonging to the Oomycota, fungi of the genera Fusarium, Mucor, and Penicillium, were sensitive to CuNPs and did not occur on CuNP_3weeks seeds. The significant reduction in the number of taxa and the most favorable structure of trophic groups being found on the CuNP_3weeks seeds suggest that NPs could potentially replace traditional fungicides for seed treatment.
Fungal community diversity in soils under pedunculate oak Quercus robur L. and European beech Fagus sylvatica L. saplings produced with different technologies
Effect of Irrigation Dose on Powdery Mildew Incidence and Root Biomass of Sessile Oaks (Quercus petraea (Matt.) Liebl.)
The sessile oak is one of the most significant forest tree species in Europe. This species is vulnerable to various stresses, among which drought and powdery mildew have been the most serious threats. The aim of this study was to determine the influence of irrigation levels (overhead sprinklers) on the damage caused by powdery mildew to Quercus petraea growing in a nursery setting. Four irrigation rates were used: 100%, 75%, 50% and 25% of the full rate. The area of the leaves was measured and the ratio between the dry mass of the roots and the dry mass of the entire plant was calculated after the growing season in years’ 2015 and 2016. Limiting the total amount of water provided to a level between 53.6 mm × m−2 and 83.6 mm × m−2, particularly in the months when total precipitation was low (VII and VIII 2015), a supplemental irrigation rate between 3 and 9 mm × m−2 resulted in a lower severity of oak powdery mildew on leaves and lead to a favorable allocation of the biomass of the sessile oak seedlings to the root system. The severity of infection on oak leaf blades was lower when irrigation rates were reduced. The greatest mean degree of infestation in 2015 was noted in the 100% irrigation rate (14.6%), 75% (6.25%), 50% (4.35%) and 25% (5.47%). In 2016, there was no significant difference between the mean area of leaves infected by powdery mildew depending on the applied irrigation rate. The shoot-root biomass rate showed greater variation under limited irrigation rates. Controlling the irrigation rate can become an effective component of integrated protection strategies against this pathogen.
The community of soil fungi associated with the western red cedar (Thuja plicata Donn ex D. Don, 1824)
ABSTRACT The western red cedar (Thuja plicata Donn ex D. Don), an important forest-forming species in the Western part of the North American continent, is an alien species naturalised in Europe. It is popular and highly valued in horticulture. While considering the progressing climate change, it may also be a potential alternative to native species in European forests. The community of soil fungi associated with the western red cedar in forested areas of Europe has not been fully determined. Thus, this study is aimed to identify the community of soil fungi associated with the western red cedar. The experimental plots are located in the Kościan Forest District (51°98’87″ N; 16°23’54″ E). All soil samples were taken from the topsoil layer at a depth of 25 cm with a trowel, three from the centre of natural regeneration (1G, 2G, 5G) and three from the centre stand under the canopy of old-growth western red cedar (3G, 4G, 6G). Fungi were identified directly from the soil based on the ITS1 rDNA region. The derived product was sequenced using Illumina’s sequencing by synthesis (SBS) technology. Sequences were referred to the National Center for Biotechnology Information (NCBI) database applying the BLAST algorithm. The fungal counts were defined based on the number of operational taxonomic units (OTU) in the sample. The OTU number was 835 206, with fungal isolates accounting for 683 095 (81.79%). A total of 8 591 taxa belonging to the Kingdom Fungi were identified. The species with the greatest shares in the community included Mortierella spp. (10.5%), Russula spp. (5.6%), Hydnum spp. (3.44%), Solicoccozyma spp. (3.1%) and Penicillium spp. (2.2%). Results showed that saprotrophs and mycorrhizal fungi predominated in the community. The dominance of ectomycorrhizal fungi over arbuscular ones, quite impressive natural regeneration was shown in T. plicata stands in Kościan. Subsequent research should take into account tree stands in Poland in which natural regeneration does not occur or occurs sporadically.
Remotely sensed localised primary production anomalies predict the burden and community structure of infection in long‐term rodent datasets
AbstractThe increasing frequency and cost of zoonotic disease emergence due to global change have led to calls for the primary surveillance of wildlife. This should be facilitated by the ready availability of remotely sensed environmental data, given the importance of the environment in determining infectious disease dynamics. However, there has been little evaluation of the temporal predictiveness of remotely sensed environmental data for infection reservoirs in vertebrate hosts due to a deficit of corresponding high‐quality long‐term infection datasets. Here we employ two unique decade‐spanning datasets for assemblages of infectious agents, including zoonotic agents, in rodents in stable habitats. Such stable habitats are important, as they provide the baseline sets of pathogens for the interactions within degrading habitats that have been identified as hotspots for zoonotic emergence. We focus on the enhanced vegetation index (EVI), a measure of vegetation greening that equates to primary productivity, reasoning that this would modulate infectious agent populations via trophic cascades determining host population density or immunocompetence. We found that EVI, in analyses with data standardised by site, inversely predicted more than one‐third of the variation in an index of infectious agent total abundance. Moreover, in bipartite host occupancy networks, weighted network statistics (connectance and modularity) were linked to total abundance and were also predicted by EVI. Infectious agent abundance and, perhaps, community structure are likely to influence infection risk and, in turn, the probability of transboundary emergence. Thus, the present results, which were consistent in disparate forest and desert systems, provide proof‐of‐principle that within‐site fluctuations in satellite‐derived greenness indices can furnish useful forecasting that could focus primary surveillance. In relation to the well‐documented global greening trend of recent decades, the present results predict declining infection burden in wild vertebrates in stable habitats; but if greening trends were to be reversed, this might magnify the already upwards trend in zoonotic emergence.
Molecular identification of cestodes from rodents in the Mazury Lake District region of Poland
Abstract Rodents serve as hosts for many species of parasites, including cestodes, but the taxonomy of rodent-infecting tapeworms, especially in Central Europe, is still understudied. Therefore, the current study was conducted to identify larval and adult cestodes in free-living rodents from Northeastern Poland. The fieldwork was conducted between 2014 and 2023 in three forest sites. Cestodes were collected from five rodent species ( Clethrionomys glareolus, Alexandromys oeconomus , Microtus agrestis, Apodemus agrarius and A. flavicollis , and were identified through morphology and by several genetic markers (12S rDNA, cox1, nad 1 , 28S rDNA , 12S-16S rDNA) using phylogenetic analyses. A total of 58 cestode specimens were analyzed using molecular and phylogenetic analyses. Species identified included Catenotaenia henttoneni, Spasskijela kratochvili, Mesocestoides litteratus, Mesocestoides melesi , and others. Three Paranoplocephala specimens were identified as P. kalelai based on nad1 sequences. Morphological and genetic analyses indicated that the dominant adult cestode in bank vole was C. henttoneni and Mesocestoides spp. were the dominant larval cestodes. This study combined genetic and morphological methods to identify the cestodes infecting rodents in Poland. It confirmed the existence of P. kalelai in Poland, suggesting that previously reported Paranoplocephala spp., identified by morphological characters, may have corresponded to this molecularly identified species. Our study also highlighted gaps in genetic databases that currently still do not allow precise species identification.
Effects of nursery production methods on fungal community diversity within soil and roots of Abies alba Mill.
AbstractThe aim of this study was to elucidate how different nursery production methods influence the composition of and relationship between soil and root community levels of Abies alba. In the Międzylesie Forest District, we quantified the responses of samples of both community-level fine roots and surrounding soil to environmental changes evoked by various seedling production methods. Fungi levels were identified based on their ITS 1 region and 5.8 S rDNA component. Analysis was conducted using Illumina SBS technology, and the obtained sequences were compared with reference samples deposited in the UNITE. Chemical analysis of the soil was also performed. Different nursery production methods resulted in a strong decoupling in the responses of fungal community levels between soil and roots. Changes in growth conditions imposed by production methods were significant in determining species composition. We found differences in fungal communities among functional groups of samples. In the soil, the dominant species of mycorrhizal fungi were Tylospora asterophora, Amanita rubescens, and Russula ionochlora. Mycorrhizal fungi in roots included Tuber anniae, Thelephoraceae sp., and Acephala applanata. Specific soil substrate conditions significantly influenced fungal community composition, leading to an increase in abundance of mycorrhizal fungi, specifically T. anniae.
Influence of the methods of seedlings production of silver fir on diversity of root fungi in forest crop
The Community of Fine Root Fungi of Silver Fir (Abies alba Mill.) Saplings
This study aimed to assess the biodiversity of fungi colonizing the fine roots (diameter up to 2 mm) of 3-year-old silver fir saplings from areas of Międzylesie Forest District in Poland. It was hypothesized that quantitatively and qualitatively, mycorrhizal fungi would be the dominant fungi in root communities of silver fir. DNA extraction was performed using Plant Genomic DNA purification. The internal transcribed spacer1 (ITS1) rDNA region was amplified using specific primers, and the amplicons were purified and sequenced using sequencing by synthesis (SBS) Illumina technology. The obtained sequences were compared with reference sequences in the UNITE database (https://unite.ut.ee/) using the basic local alignment search tool (BLAST) algorithm to facilitate species identification. A total of 307,511 OTUs was obtained from each sample. There were 246,477 OTUs (80.15%) of fungi known from cultures. The genera Tuber spp. (7.51%) and Acephala spp. (3.23%) accounted for the largest share of the fungal communities on the fine roots of fir trees. Hence our results indicate the dominance of mycorrhizal fungi in these communities and reflect the excellent quality of the saplings that were assessed. Pathogenic fungi constituted a much smaller share of the fungal communities.
Heligmosomid infections in bank voles are associated with higher prevalence and greater abundance of other helminth species
Variability of Functional Groups of Rhizosphere Fungi of Norway Spruce (Picea abies (L.) H.Karst.) in the Boreal Range: The Wigry National Park, Poland
Rhizosphere microbial communities can influence plant growth and development. Natural regeneration processes take place in the tree stands of protected areas, which makes it possible to observe the natural changes taking place in the rhizosphere along with the development of the plants. This study aimed to determine the diversity (taxonomic and functional) of the rhizosphere fungal communities of Norway spruce growing in one of four developmental stages. Our research was based on the ITS region using Illumina system sequencing. Saprotrophs dominated in the studied rhizospheres, but their percentage share decreased with the age of the development group (for 51.91 from 43.13%). However, in the case of mycorrhizal fungi, an opposite trend was observed (16.96–26.75%). The most numerous genera were: saprotrophic Aspergillus (2.54–3.83%), Penicillium (6.47–12.86%), Pyrenochaeta (1.39–11.78%), pathogenic Curvularia (0.53–4.39%), and mycorrhizal Cortinarius (1.80–5.46%), Pseudotomentella (2.94–5.64%) and Tomentella (4.54–15.94%). The species composition of rhizosphere fungal communities was favorable for the regeneration of natural spruce and the development of multi-generational Norway spruce stands. The ratio of the abundance of saprotrophic and mycorrhizal fungi to the abundance of pathogens was high and promising for the durability of the large proportion of spruce in the Wigry National Park and for forest ecosystems in general.
Interplay between vertebrate adaptive immunity and bacterial infectivity genes: Bank vole MHC versus Borrelia afzelii OspC
AbstractCoevolution of parasites with their hosts may lead to balancing selection on genes involved in determining the specificity of host–parasite interactions, but examples of such specific interactions in wild vertebrates are scarce. Here, we investigated whether the polymorphic outer surface protein C (OspC), used by the Lyme disease agent, Borrelia afzelii, to manipulate vertebrate host innate immunity, interacts with polymorphic major histocompatibility genes (MHC), while concurrently eliciting a strong antibody response, in one of its main hosts in Europe, the bank vole. We found signals of balancing selection acting on OspC, resulting in little differentiation in OspC variant frequencies between years. Neither MHC alleles nor their inferred functional groupings (supertypes) significantly predicted the specificity of infection with strains carrying different OspC variants. However, we found that MHC alleles, but not supertypes, significantly predicted the level of IgG antibodies against two common OspC variants among seropositive individuals. Our results thus indicate that MHC alleles differ in their ability to induce antibody responses against specific OspC variants, which may contribute to selection of OspC polymorphism by the vole immune system.
Mycobiome of Post-Agricultural Soils 20 Years after Application of Organic Substrates and Planting of Pine Seedlings
A 20-year study of a pine stand on post-agricultural land showed that woody debris in the form of organic matter can be successfully used to restore symbiotic mycorrhizal communities, as is the case with forest soils. Woody substrates restored organic matter in soils altered by long agricultural use and had a positive effect on the composition of mycobiota antagonistic to pathogens, especially to Heterobasidion annosum, the causal agent of the dangerous disease root and stump rot of many forest tree species, including stands of Pinus sylvestris (L.). In a study that started in 2001 in the forest district of Czarne Człuchowskie (northern Poland), the following organic materials were used: wood residues (W), sawdust (S), bark compost (B), and compost applied to the root zone during planting (G). The organic materials were spread in the form of mulch over the entire area during planting. After twenty years, it was found that the substrates used provided suitable growth conditions for mycobiome useful for pines. The addition of organic matter did not change the alpha biodiversity of the soil, but in the long term led to significant changes in the composition of mycobiota (beta biodiversity). The changes in the soil after the addition of organic material naturally accelerated the formation of the forest habitat. A number of fungi evolved that degraded added lignin and cellulose while being antagonists of H. annosum and other pine pathogens. In particular, the well-known hyperpathogens of the genus Trichoderma played an important role by promoting resistance of the soil environment to pathogens. Soil enrichment by bark compost and wood residues increased the relative abundance of Trichoderma more than fourfold.Mycorrhizal fungi became dominant in soil enriched with organic matter. After enriching the soil with bark compost, the relative abundance of Amphinema and Inocybe increased to 5%. The relative abundance of Russula in soil enriched with wood residues and sawdust increased to 9% and 5%, respectively. Mycorrhizal fungi, e.g., of the genus Ąmanita, Rusula, which formed root mycorrhizae, not only increased the root receiving area many times over, but also protected the roots (mechanically and chemically from pathogens). Altogether, the observed positive changes increase the chances that the first generation of pines will survive on the ground.
