Spore Dispersal Research Articles

Ophiocordyceps : Fungi Entomopatogen Penyebab Zombie Pada Serangga

Ophiocordyceps is special type of entomopathogenic fungi which well known to infect insects and turning them into zombie. A total of 250 species have been described from its genus, and some are known to control their hosts, which are most notably ants. They are ubiquitous within tropical rain forests across the board, with few publication reports from temperate ecosystems. These fungal pathogens possess the capacity to manipulate host behaviour in order to increase their own fitness. These entomopathogenic fungi cause their hosts frezee to die in an exposed area on the abaxial surface of leaves or branches, which then enhancing the fungus spore production and dispersal. Despite the high diversity of fungi and insect with vast tropical forest as well as drugs potency from Ophiocordyceps, publication of Ophiocordyces was rarely reported from Indonesia. This review will explain the evolution of Ophiocordyceps-insect interaction, simbiont distribution, and zombie-insect formation mechanism, in order to induce zombie-insect research in Indonesia.

Squirrel consuming “poisonous” mushrooms

The representative toadstool Amanita muscaria plays an important role in maintaining forest ecosystems by forming mutualistic associations with a variety of trees. A muscaria is also known for the poisonous properties of its hallucinogenic constituents, namely, ibotenic acid, muscimol, and muscarin. Serious cases of poisoning in humans may involve deliria, hallucinations, seizures, and (rarely) death. A typical symptom is visual distortion of the size of objects, a phenomenon that formed the basis of the mind-altering events described in Lewis Carroll’s 1865 novel Alice’s Adventures in Wonderland. Interestingly, we observed a Japanese squirrel (Sciurus lis) routinely feed not only on A muscaria but also on other Amanita species that are also poisonous to humans. This squirrel returned to feed on Amanita fruiting bodies for several days, indicating that it could safely consume the “poisonous” mushrooms. The ecological roles of fungal toxins remain largely unexplored. One possible role is to deter fungivores. However, fungivores are not always disadvantageous to Amanita, because they may disperse intact spores via their digestive tracts. Perhaps Amanita mushrooms facilitate mutualisms with toxin-resistant squirrels, which can disperse viable spores, while deterring toxin-susceptible enemies, which could negatively impact spore survival. If so, potential dispersal of fungal spores by squirrels is analogous to a seed dispersal mutualism, in which a plant offers a reward to an animal as a seed disperser. How do squirrels safely eat Amanita mushrooms? What role do squirrels play in Amanita spore dispersal? How would squirrel-assisted spore dispersal contribute to the establishment of ectomycorrhizal relationships within these ecosystems? These questions warrant further investigation.

Fungal ecology: Truffle-guzzling birds

A new study of truffle fungi in Patagonia reveals the importance of native bird species in spore dispersal. This has wide implications for the study of animal-fungal symbioses in the Southern Hemisphere.

Diversity, Dispersal and Mode of Reproduction of Amanita exitialis in Southern China.

Amanita exitialis is a poisonous mushroom and has caused many deaths in southern China. In this study, we collected 118 fruiting bodies of A. exitialis from seven different sites in Guangdong Province in southern China and investigated their genetic relationships using 14 polymorphic molecular markers. These 14 markers grouped the 118 fruiting bodies into 20 multilocus genotypes. Among these 20 genotypes, eight were each found only once while the remaining 12 were each represented by two to 54 fruiting bodies. Interestingly, among the 12 shared genotypes, four were shared between/among local populations that were separated by as far as over 80 km, a result consistent with secondary homothallic reproduction and long-distance spore dispersal. Despite the observed gene flow, significant genetic differentiations were found among the local populations, primarily due to the over-representation of certain genotypes within individual local populations. STRUCTURE analyses revealed that the 118 fruiting bodies belonged to three genetic clusters, consistent with divergence within this species in this geographic region. Interestingly, we found an excess of heterozygous individuals at both the local and the total sample level, suggesting potential inbreeding depression and heterozygous advantage in these populations of A. exitialis. We discuss the implications of our results for understanding the life cycle, dispersal, and evolution of this poisonous mushroom.

Fern fronds that move like pine cones: humidity-driven motion of fertile leaflets governs the timing of spore dispersal in a widespread fern species.

The sensitive fern, Onoclea sensibilis, is a widespread species in eastern North America and has an atypical timing of spore dispersal among temperate ferns. During early summer, this dimorphic species produces heavily modified spore-bearing fronds with leaflets tightly enveloping their sporangia and spores. These fronds senesce and persist above ground as dead mature structures until the following early spring when the leaflets finally open and spores are dispersed. While this timing of spore dispersal has been observed for over 120 years, the structural mechanisms underpinning this phenology have remained elusive. Based on field observations, growth chamber manipulations and scanning electron microscopy, the mechanisms underlying this distinctive timing of spore dispersal in the sensitive fern were investigated. I show that fertile leaflets of the sensitive fern move in direct response to changes in humidity, exhibiting structural and functional parallels with multicellular hygromorphic structures in seed plants, such as pine cones. These parallels include differences in cellulose microfibril orientation in cells on the abaxial and adaxial sides of the leaflet. The dynamics of this hygroscopic movement concomitant with regular abscission zones along the pinnules and coordinated senescence lead to the specific timing of early spring spore dispersal in the sensitive fern. While hygroscopic movement is common in seed-free plants, it mostly occurs in small structures that are either one or a few cells in size, such as the leptosporangium. Given its multicellular structure and integration across many cells and tissues, the movement and construction of the sensitive fern pinnules are more similar to structures in seed plants. The evolution of this complex trait in the sensitive fern efficiently regulates the timing of spore release, leading to early spring dispersal. This phenology likely gives gametophytes and subsequent sporophytes an advantage with early germination and growth.

Potential role of nitrogen in spore dispersal and infection of Paraphysoderma sedebokerense, a fungal parasite of Haematococcus pluvialis

Paraphysoderma sedebokerense, a parasitic fungus in Blastocladiomycota, can infect the microalga Haematococcus pluvialis and cause culture crashes. The early development including encystment and cyst germination of P. sedebokerense on microalgal cell walls is vital to the parasitism process. To evaluate the potential role of nitrogen in the early development of P. sedebokerense, we analyzed colony formation of P. sedebokerense on agar plates containing inorganic nitrogen (i.e., nitrate), transcriptome of P. sedebokerense during encystment and penetration, amino acid utilization by P. sedebokerense and amino acid profile of microalgal cell walls. Results indicated that nitrate facilitated the dispersal of amoeboid swarmers from sporangia. Transcriptome analysis indicated that Gene Ontology (GO) terms related to nitrate assimilation and methionine biosynthesis were enriched in P. sedebokerense when it encysted and penetrated the microalgal cell walls. Furthermore, amoeboid swarmers can encyst and penetrate the extracellular glycoproteinaceous matrix of microalgal aplanospores. These results suggested that organic nitrogen was involved in the early development of P. sedebokerense on microalgal cell walls. In addition, most of the abundant amino acids from the algal host were the preferable ones for fungal growth (i.e., l-alanine, l-arginine, l-glutamic acid and glycine). However, P. sedebokerense cannot directly utilize methionine, and methionine or amino acid biosynthesis inhibitors (i.e., pyrimethanil and cyprodinil) completely abolished the parasitism process. These evidences revealed that methionine biosynthesis in the fungal pathogen was essential for the parasitism process, and methionine or amino acid biosynthesis inhibitors are effective for disease control.

First report of stem rust, caused by Puccinia graminis, and crown rust, caused by Puccinia coronata var. avenae f. sp. avenae, on tall fescue (Festuca arundinacea) in Georgia, USA.

Stem rust, caused by Puccinia graminis, and crown rust, caused by P. coronata, are common rust diseases on cool-season grasses (Karakkat et al. 2018), for which long-distance spore dispersal was recorded in northern US (Harder and Haber 1992). During the summers of 2019 and 2020, severe infection of stem rust and crown rust was observed on > 60% of tall fescue (Festuca arundinacea) germplasm plants in a breeding nursery located at the University of Georgia, Griffin GA. Rust-infected leaves first presented uredinia pustules, then black telia towards the end of the season. The uredinia pustules of stem rust and crown rust were brick-red and, yellow and arranged along the host veins, respectively. The urediniospores were one-celled, round to ovoid and measured from 20.75±2.44 μm (crown rust) to 27±3.60 μm long (stem rust). The teliospores were two-celled and measured from 45.75±10.14 μm (stem rust) to 51.60±4.0 μm long (crown rust) (Leonard et al. 2005; Cummins 1971). Urediniospores of both rusts were collected from infected plants in the field in April of 2020 using a Piston vacuum pump (Welch by Gardner Denver Ltd.) and stored at -80 °C in 1.5 ml Eppendorf tubes. Genomic DNA was extracted by grinding the urediniospores in liquid nitrogen using mortar and pestle, followed by the cetyltrimethylammonium bromide method (Doyle and Doyle 1987). The internal transcribed spacer (ITS) region of the ribosomal DNA was amplified using the ITS5-ITS4 primers (White et al. 1990). BLASTn and phylogenetic analyses revealed that the sequence of stem rust (GenBank acc. no. MW430963) and crown rust (GenBank acc. no. MW431324) pathogens had >99% similarity with P. graminis (GenBank acc. no. HQ317538) and P. coronata var. avenae f. sp. avenae (clade V; Liu and Hambleton 2013) (GenBank acc. no. EU014044), respectively. Pathogenicity tests were conducted on the tall fescue cultivar 'Bandit'. For each rust, 12 pots (10 cm × 10 cm) were planted, each containing 13 seeds in a Sungro professional growing mix soil (Sun Gro Horticulture Distribution Inc.). The plant materials were kept in the greenhouse at 20°C/ 25°C (night/day),15-hrs of light, and watered twice a week for 4-weeks. Urediniospores were recovered from -80°C and allowed to acclimate at room temperature for 1 h. For each rust, 20 ml of suspension containing 1×105 urediniospores ml-1 and 5 μl of Tween-twenty (Agdia Inc. Elkhart, IN) were used to inoculate 6 pots; while 6 control pots were sprayed with sterile water. After inoculation, plants were allowed to dry for 1 h and then transferred to a dark chamber at 20°C and 90% of humidity for 12-15 h. At 10-days post inoculation, all inoculated plants developed rust symptoms identical to those observed in the field, whereas control plants had no symptoms. Stem and crown rust pathogens were re-isolated from the artificially inoculated tall fescue plants. Based on form, size, color and numbers of cells forming the spores, a 1947 Festuca elatior specimen from Georgia mentioning Puccinia coronata (Hanlin 1966), held at the Julian H. Miller Mycological Herbarium (Catalog No. GAM00013162), was discarded as an earlier record of P. coronata var. avenae and could have been misdiagnosed. Due to the fragile integrity of the original infected plant sample as well as the incipient infection, DNA identification was unsuccessful. To our knowledge, this is the first morphological, genetic and taxonomic report of P. graminis and P. coronata var. avenae f. sp. avenae on tall fescue in Georgia, USA.

Discovering the role of Patagonian birds in the dispersal of truffles and other mycorrhizal fungi

Dispersal is a key process that impacts population dynamics and structures biotic communities. Dispersal limitation influences the assembly of plant and microbial communities, including mycorrhizal fungi and their plant hosts. Mycorrhizal fungi play key ecological roles in forests by feeding nutrients to plants in exchange for sugars, so the dispersal of mycorrhizal fungi spores actively shapes plant communities. Although many fungi rely on wind for spore dispersal, some fungi have lost the ability to shoot their spores into the air and instead produce enclosed belowground fruiting bodies (truffles) that rely on animals for dispersal. The role of mammals in fungal spore dispersal is well documented, but the relevance of birds as dispersal agents of fungi has been understudied, despite the prominence of birds as seed dispersal vectors. Here, we use metagenomics and epifluorescence microscopy to demonstrate that two common, widespread, and endemic Patagonian birds, chucao tapaculos (Scelorchilus rubecula) and black-throated huet-huets (Pteroptochos tarnii), regularly consume mycorrhizal fungi and disperse viable spores via mycophagy. Our metagenomic analysis indicates that these birds routinely consume diverse mycorrhizal fungi, including many truffles, that are symbiotically associated with Nothofagaceae trees that dominate Patagonian forests. Epifluorescence microscopy of fecal samples confirmed that the birds dispersed copious viable spores from truffles and other mycorrhizal fungi. We show that fungi are a common food for both bird species and that this animal-fungi symbiosis is widespread and ecologically important in Patagonia. Our findings indicate that birds may also act as cryptic but critical fungal dispersal agents in other ecosystems.

Genetic variation and reproductive patterns in wetland mosses suggest efficient initial colonization of disturbed sites.

To understand colonization processes, it is critical to fully assess the role of dispersal in shaping biogeographical patterns at the gene, individual, population, and community levels. We test two alternative hypotheses (H I and H II) for the colonization of disturbed sites by clonal plants, by analyzing intraspecific genetic variation in one and reproductive traits in two typical fen mosses with separate sexes and intermittent spore dispersal, comparing disturbed, early‐succession (limed) fens and late‐successional rich fens. H I suggests initial colonization of disturbed sites by diverse genotypes of which fewer remain in late‐successional fens and an initially balanced sex ratio that develops into a possibly skewed population sex ratio. H II suggests initial colonization by few genotypes and gradual accumulation of additional genotypes and an initially skewed sex ratio that alters into the species‐specific sex ratio, during succession. Under both scenarios, we expect enhanced sexual reproduction in late‐successional fens due to resource gains and decreased intermate distances when clones expand. We show that the intraspecific genetic diversity, assessed by two molecular markers, in Scorpidium cossonii was higher and the genetic variation among sites was smaller in disturbed than late‐successional rich fens. Sex ratio was balanced in S. cossonii and Campylium stellatum in disturbed fens and skewed in C. stellatum in late‐successional fens, thus supporting H I. In line with our prediction, sex expression incidence was higher in, and sporophytes were confined to, late‐succession compared to disturbed rich fens. Late‐successional S. cossonii sites had more within‐site patches with two or more genotypes, and both species displayed higher sex expression levels in late‐successional than in disturbed sites. We conclude that diverse genotypes and both sexes disperse efficiently to, and successfully colonize new sites, while patterns of genetic variation and sexual reproduction in late‐successional rich fens are gradually shaped by local conditions and interactions over extended time periods.

Spatiotemporal distribution and the passive dispersal of fungal spores through HVAC systems

Spatiotemporal distribution and the passive dispersal of fungal spores through HVAC systems

Weather Conditions Conducive for the Early-Season Production and Dispersal of Cercospora beticola Spores in the Great Lakes Region of North America.

In many parts of the world including the Great Lakes region of North America, Cercospora leaf spot (CLS), caused by the fungal pathogen Cercospora beticola, is a major foliar disease of sugar beet (Beta vulgaris). Management of CLS involves an integrated approach which includes the application of fungicides. To guide fungicide application timings, disease prediction models are widely used by sugar beet growers in North America. While these models have generally worked well, they have not included information about pathogen presence. Thus, incorporating spore production and dispersal could make them more effective. The current study used sentinel beets to assess the presence of C. beticola spores in the environment early in the 2017 and 2018 growing seasons. Weather variables including air temperature, relative humidity, rainfall, leaf wetness, wind speed, and solar radiation were collected. These data were used to identify environmental variables that correlated with spore levels during a time when CLS is not generally observed in commercial fields. C. beticola spores were detected during mid-April both years, which is much earlier than previously reported. A correlation was found between spore data and all the weather variables examined during at least one of the two years, except for air temperature. In both years, spore presence was significantly correlated with rainfall (P < 0.0001) as well as relative humidity (P < 0.0090). Rainfall was particularly intriguing, with an adjusted R2 of 0.3135 in 2017 and 0.1652 in 2018. Efforts are ongoing to investigate information on spore presence to improve prediction models and CLS management.

Dynamics of Diaporthe ampelina Conidia Released from Grape Canes that Overwintered in the Vineyard.

Phomopsis cane and leaf spot (PCLS) is an important disease of grapevines that is mainly caused by Diaporthe ampelina. Dispersal dynamics of D. ampelina spores were investigated in two vineyards, one in northern Italy and one in Montenegro, by using spore samplers that collected α- and β-conidia from rain water running off from PCLS-affected canes. The canes were collected from each vineyard, deployed, and overwintered in the corresponding vineyards. In each of three years (2016, 2017, and 2018), conidial dispersal was investigated during one (Montenegro) or two (Italy) growing seasons following the deployment of the PCLS-affected canes. In the first growing season following cane deployment in both vineyards, α-conidia were mostly found in runoff water after grapevine bud break, especially in April and May, and β-conidia were regularly found in numbers comparable to those of α-conidia, most frequently from June to September. In Italy, high numbers of α- and β-conidia were also collected during the second growing season following cane deployment. The dispersal dynamics of α-conidia over time were described by a Gompertz equation using hydrothermal time (i.e., the accumulated effect of temperature on the maturation rate of pycnidia on days in which the number of hours of wetness was ≥6 or 9 h), with R2 and concordance correlation coefficient >0.9. Rain (≥0.2 mm) was a good predictor of conidial dispersal, with an overall accuracy of 0.97. These results increase our understanding of D. ampelina spore dispersal and should be integrated into warning systems for PCLS management.

Impact of Agro-met Conditions and Crop Growth Stages on the Progression of Brown Spot Disease in Basmati Rice

The present study was carried out at Crop Research Centre of SVPUAT Meerut, U.P during three cropping seasons i.e. 2018, 2019 and 2020 using basmati rice as test cultivar. The study was primarily focused upon the combined effect of weather parameters and crop growth stages of rice crop on the progression of brown spot disease. It was noticed that disease was first observed at late vegetative stage in every cropping season viz. 2018, 2019 and 2020 and reached its maximum towards maturity phase of the crop by obtaining total AUDPC’S of 1049.3, 1170.74 and 852.6 respectively. A significant negative correlation between weekly percent disease index (PDI) and T-max &amp; T-min was obtained recording correlation coefficients (r) of (- 0.71 &amp; - 0.98), (- 0.88 &amp; - 0.98) and (- 0.63 &amp; - 0.98) during 2018, 2019 and 2020 respectively indicating decline in maximum and minimum temperatures at the terminal stages of the crop can greatly favor disease progression. A non-significant positive correlation was obtained between weekly m-RH and PDI to the end of every crop season. During the year 2020, a highly significant negative correlation was obtained between weekly a-RH and PDI (r = - 0.803) in contrast with the years 2018 (r = - 0.55) and 2019 (r = -0.477) exhibiting non-significant negative correlation which might be the reason for low PDI during the year 2020 due to greater decline in relative humidity to the end of the crop season. Although, a non-significant negative correlation between weekly PDI and RF (rainfall) and partial positive correlation with weekly bright sunshine hours (BSS) was obtained during all three crop seasons, high intermittent rainfall from late vegetative to reproductive stage during 2018 and 2019 might be responsible for large amount of spore dispersal (high inoculum pressure) leading to greater disease progression. The regression model developed using 2018, 2019 and 2020 meteorological data, which was validated with disease severity data of 2019 yielded significant R2 value of 0.98 using observed and predicted values.

A general trait-based modelling framework for revealing patterns of airborne fungal dispersal threats to agriculture and native flora.

Fungal plant pathogens are of economic and ecological importance to global agriculture and natural ecosystems. Long-distance atmospheric dispersal of fungal spores (LAD) can pose threats to agricultural and native vegetation lands. An understanding of such patterns of fungal spore dispersal and invasion pathways can provide valuable insights into plant protection. Spore traits affect their dispersal abilities. We propose a general trait-based framework for modelling LAD to reveal dispersal patterns and pathways, and assess subsequent threats of arrival (TOA) quantitatively in the context of biosecurity. To illustrate the framework, we present a study of Australia and its surrounding land masses. The overall dispersal pattern covered almost the entire continent of Australia. Fungal spores in the size class of 10 and 20µm (aerodynamic diameter) posed the greatest TOA. Our study shows the effects of morphological traits on these potential TOA, and how they varied between source regions, size classes, and seasons. Our framework revealed spore dispersal patterns and pathways. It also facilitates comparisons of spatio-temporal dispersal dynamics among fungal classes, gaining insights into atmospheric long-distance dispersal of fungi as a whole, and provides a basis for assessing fungal pest threats in potential source regions based on easily measured spore characteristics.

Synergistic dispersal of plant pathogen spores by jumping-droplet condensation and wind

Plant pathogens are responsible for the annual yield loss of crops worldwide and pose a significant threat to global food security. A necessary prelude to many plant disease epidemics is the short-range dispersal of spores, which may generate several disease foci within a field. New information is needed on the mechanisms of plant pathogen spread within and among susceptible plants. Here, we show that self-propelled jumping dew droplets, working synergistically with low wind flow, can propel spores of a fungal plant pathogen (wheat leaf rust) beyond the quiescent boundary layer and disperse them onto neighboring leaves downwind. An array of horizontal water-sensitive papers was used to mimic healthy wheat leaves and showed that up to 25 spores/h may be deposited on a single leaf downwind of the infected leaf during a single dew cycle. These findings reveal that a single dew cycle can disperse copious numbers of fungal spores to other wheat plants, even in the absence of rain splash or strong gusts of wind.

Study on spore release of Polytrichum commune Hedw. var. commune by synergetic effects of sub-hygroscopic movement and wind.

The effect of humidity change on spore release of the Nematodontae Polytrichaceae has never been tested experimentally. Similarly, the impact of humidity alterations on structure of the peristome have never been studied. Polytrichum commune Hedw. var. commune from Guizhou Province, China, was selected as the research object to examine effects of simulated wind in the laboratory. By controlling humidity and wind, the mechanism of spore dispersal was revealed. When humidity increased, the size of the peristome and epiphragm enlarged significantly (the peristome has no obvious spatial displacement, unlike the hygroscopic movement of Arthrodontae mosses. Thus, we named it 'sub-hygroscopic movement'), then recovered to normal size when humidity decreased. When humidity was controlled and wind applied, the scattering of spores gradually decreased as the capsule dried out and finally reached a very low level; when the capsule was wetted or rewetted, the amount of spores released rose and returned to the initial state. Through comparison of moist and dry capsules, only enhanced humidity of the sporophytes led to increases in spore release. The results show that the dispersal of spores was significantly improved in windy conditions and the sub-hygroscopic movement of the capsule peristome, which ensure the continuity and effectiveness of P. commune reproduction.

Functional, temporal and spatial complementarity in mammal‐fungal spore networks enhances mycorrhizal dispersal following forest harvesting

Abstract Animals that disperse plant or fungal propagules following forest disturbances, including timber harvests, play an important role during forest regeneration by dispersing seeds or spores from intact communities to disturbed sites. Determining how complementary or redundant animal species are as dispersers of propagules is key to understanding the stability of dispersal dynamics and informing management practices. Here we examine the functional, temporal and spatial components of mycorrhizal fungal spore dispersal by small mammals (rodents and shrews) following timber harvest. We tracked the interactions of seven mammal species and 34 fungal taxa composed of two mycorrhizal functional types, arbuscular mycorrhizae (AM) and ectomycorrhizae (ECM), in 11 patch cuts (0.4 ha) distributed across hardwood and mixedwood forest in the north‐eastern United States. Over a 2‐year period directly following harvests, we measured the relative contribution of mammal species to spore dispersal using networks that integrated mammal abundance with spore loads in scat. We also measured species‐specific microhabitat associations. Mammals were complementary in their dispersal of AM and ECM fungal spores. However, within AM dispersal networks, mammals were redundant, with asynchrony in mammal population fluctuations among years leading to changes in the relative importance of mammal species. Comparatively, ECM fungal spore consumption and dispersal was primarily provided by one rodent species (Myodes gapperi), resulting in dispersal networks that were highly specialized. This indicates that AM spore dispersal is more robust to changes in mammal community turnover compared to ECM spore dispersal. Mammal species varied from having no microhabitat associations to associating with a variety of different forest structure and ground cover conditions, indicating that species play different roles from broadcasting spores widely to depositing spores in discrete locations. By preserving microhabitat characteristics that are associated with small mammals in harvested areas, particularly downed wood and patches of pre‐harvest vegetation, forest managers can help maintain dispersal of mycorrhizal fungi. A free Plain Language Summary can be found within the Supporting Information of this article.

Octopus stinkhorn Clathrus archeri (Berk.) Dring, an alien stinkhorn fungus (Phallaceae), in north-eastern Poland

Distribution of an alien fungus, octopus stinkhorn Clathrus archeri, has been studied in north-eastern Poland. The closest earlier known localities of this species, situated north of the new ones, were reported near the village of Dymnica (Lębork County) in Poland and near the town of Kartena in Lithuania. Field research was conducted in May–November in 2019-2020 and information from naturalists and foresters was verified, to map this species and draw attention to the problem of appearance of alien fungal species in forests. In the locality where the largest number of basidiomata was found, they were measured every day from 12 October till 2 November 2020: height and width of young ones at the egg phase, height of mature ones, and length of their longest arms. Additionally, arms of individual basidiomata were counted. We have documented 7 localities of C. archeri, including 5 situated in forests and 2 in other habitats. In total, we found 63 basidiomata of this species. In the localities outside forests, basidiomata of C. archeri appeared in places where timber was stored and the soil was covered with sawdust and pieces of bark. The other 5 localities were situated in broadleaved forests with a small proportion of coniferous species. It seems that C. archeri, when moisture level is suitable, finds favourable living conditions in fertile broadleaved forests of north-eastern Poland. It is sometimes re-moved from forest areas (e.g. with wood) to open and urbanized areas. Considering the observed climate change, we can expect a further spread of C. archeri to the north-eastern of Poland and an increase in the number of its localities in the Baltic Sea region. Spore dispersal of this species is facilitated not only by humans but also by insects. No negative impact of C. archeri on wooded habitats was noticed. Key words: Phallaceae, Clathrus archeri, octopus stinkhorn, alien species, ecology, distribution, forest, Poland

Mesofauna assemblages on the extraradical mycelium of Pinus greggii roots with three ectomycorrhizal fungi

Background: The extraradical mycelium (ERM) of ectomycorrhizal fungi is a network inhabited by soil mesofauna, mainly collembolans and mites, forming interactions during the fungal life-cycle, from grazing on hyphae to spore dispersal. However, it is still unknown if ERM of ectomycorrhizal fungi could influence the structure of mesofauna assemblages.&#x0D; Objective: To evaluate the abundance and community composition of the mesofauna inhabiting the ERM of Hebeloma mesophaeum, Laccaria laccata and Wilcoxina sp. in Pinus greggii roots.&#x0D; Methods: Mesofauna was collected from the root balls of P. greggii with 80 % of colonization using a washing method.&#x0D; Results and conclusions: An effect was observed due to ERM differences on species richness and species dominance, but not an effect on the abundance and community composition of the mesofauna. However, Wilcoxina sp. presented the lowest species richness and diversity. Fungus-feeding collembolans shaped species-rich assemblages, being isotomid-tullbergid forms the soil-dwelling taxa. Entomobryidae and Hypogastruridae were the most common families on the soil surface, not being found in Wilcoxina sp., and only a few predatory mites of the Mesostigmata and Endeostigmata were found. The ectomycorrhizal mycelium constitutes a trophic niche of the mesofauna and it might be an evolutionary force in structuring species composition and diversity.

Symbiotic nitrogen fixation in the reproductive structures of a basidiomycete fungus

Nitrogen (N) fixation is a driving force for the formation of symbiotic associations between N2-fixing bacteria and eukaryotes.1 Limited examples of these associations are known in fungi, and none with sexual structures of non-lichenized species.2-6 The basidiomycete Guyanagaster necrorhizus is a sequestrate fungus endemic to the Guiana Shield.7 Like the root rot-causing species in its sister genera Armillaria and Desarmillaria, G.necrorhizus sporocarps fruit from roots of decaying trees (Figures 1A-1C),8 and genome sequencing is consistent with observations that G.necrorhizus is a white-rotting decomposer. This species also represents the first documentation of an arthropod-dispersed sequestrate fungus. Numerous species of distantly related wood-feeding termites, which scavenge for N-rich food, feed on the mature spore-bearing tissue, or gleba, of G.necrorhizus. During feeding, mature spores adhere to termites for subsequent dispersal.9 Using chemical assays, isotope analysis, and high-throughput sequencing, we show that the sporocarps harbor actively N2-fixing Enterobacteriaceae species and that the N content within fungal tissue increases with maturation. Untargeted proteomic profiling suggests that ATP generation in the gleba is accomplished via fermentation. The use of fermentation-an anaerobic process-indicates that the sporocarp environment is anoxic, likely an adaptation to protect the oxygen-sensitive nitrogenase enzyme. Sporocarps also have a thick outer covering, possibly to limit oxygen diffusion. The enriched N content within mature sporocarps may offer a dietary inducement for termites in exchange for spore dispersal. These results show that the flexible metabolic capacity of fungi may facilitate N2-fixing associations, as well as higher-level organismal associations.