Fungal Ecology最新文献

All vascular plants contain communities of endophyte fungi within their foliar tissues. These fungi can act as plant bodyguards and disrupt the efficacy of weed biological control agents, yet studies of invasive plant biology hardly ever consider the background endophyte communities. Here, we investigated the factors that affect the structure of cultivable endophyte communities in the highly invasive weed Impatiens glandulifera. We found that community composition varies according to location, but that seasonal accumulation patterns of endophytes are similar between sites. Biotic factors influencing endophytes include arbuscular mycorrhizal fungi, insect herbivores and plant pathogens. Endophyte species richness per plant was consistently low compared with other herbaceous plants and communities appear to be a random sub-set of the available species pool, with the plant acting as a strong filter of species. This information should enable community structure to be modelled and manipulated, making biological control of this weed more effective.

Phyllosphere fungi exhibit a wide range of species and play a pivotal role in island ecosystem biodiversity. They bolster plant resilience against diseases and environmental stresses, facilitate the decomposition of organic materials, and enhance nutrient exchange between plants and their surroundings. Despite extensive research on island biogeography pertaining to flora and fauna, the assembly of phyllosphere fungal communities has not been thoroughly explored. This study addresses this gap by employing high-throughput sequencing to examine phyllosphere fungi associated with three island plant species (Messerschmidia argentea, Morinda citrifolia, and Suriana maritima) across 13 islands in the Xisha Islands region. Our findings reveal significant variances in fungal α-diversity and community composition across different islands, plant species, and functional guilds. The variation in fungal α-diversity was notably correlated with the geographical distance from the mainland and a satellite-derived vegetation index, while the Bray-Curtis similarity in fungal communities was primarily influenced by the geographical distance between islands. Stochastic elements, particularly dispersal limitation and drift, were identified as major drivers of fungal community assembly. Furthermore, we observed that island size impacts the distribution of potential keystone species and their co-occurrence patterns within the fungal groups. Intriguingly, host vegetation was found to exert a stronger selective influence on phyllosphere fungi than island characteristics. These results provide valuable insights into the complex ecological interactions and processes governing fungal communities in isolated and unique environmental settings.

This study evaluated the growth-promoting action of 16 isolates of the entomopathogenic fungal genus Metarhizium spp., representing 14 from the native pastures and two commercial isolates, on the forage grass Urochloa brizantha, via drench application to seeds. Multivariate analysis of plant height, length of the longest leaf and root, and dry and fresh weight of leaves and roots indicated the most promising isolates, five from native pastures (CEPAF_ENT25, CEPAF_ENT26, CEPAF_ENT27, CEPAF_ENT42, and CEPAF_ENT59) and one commercial (IBCB 425), all isolates of Metarhizium anisopliae. Except for isolate CEPAF_ENT59, there was a positive correlation between growth parameters of U. brizantha with the contents of chlorophyll a and b and carotenoids and with the contents of N, P, and Zn in the leaves. Endophytic colonization tests indicated the presence of Metarhizium spp. in all plant parts, most frequently in the stems. Furthermore, the selected isolates of Metarhizium spp. were recovered from the cultivation substrate and positively affected the germination and initial growth of U. brizantha. Thus, the most promising isolates have potential for application to seeds of U. brizantha.

Extreme climatic events and related disturbances such as hurricanes are increasingly altering forest ecosystems. How these events impact forest fungal communities is poorly characterized. We examined the effect of a hurricane on mycorrhizal community structure and potential interspecific fungal interactions, inferred from OTU co-occurrences. We characterized the root fungal communities of dual-mycorrhizal plants from nine plots during two consecutive years after a category four hurricane impacted the coastal Mexican Pacific tropical forest in Jalisco. Presence-abundance matrices were used to calculate properties of mycorrhizal networks including nestedness and modularity, and to infer patterns of co-occurrence. One year after the hurricane there was a loss of links between plants and fungi. Increased network modularity and connectivity were observed after two years. We also found that disturbance changed arbuscular mycorrhizal fungal network structure more strongly than ectomycorrhizal fungal networks. Fungal guilds changed their putative interspecific interactions, from mutual exclusion in the first year to a significant increase in co-occurrence of plant pathogens, saprotrophs, and endophytes in the second year. Our results suggest that in the short term, rhizospheric interactions can be resilient to hurricanes, but fungal guilds may have divergent responses.

The Phialocephala fortinii s.l. – Acephala applanata species complex (PAC) is composed of closely related endophytic ascomycetes colonizing roots of coniferous trees. Their means of dispersal and teleomorphic form are still unknown. Accordingly, we focused on vegetative mycelial spread of PAC i) via root contacts from PAC-inoculated to PAC-free saplings, ii) through semi-sterile soil from PAC-colonized to PAC-free saplings (without contact) and iii) through semi-sterile soil from PAC-colonized substrate to PAC-free saplings (without contact). Five PAC strains were selected for the experiment. All three modes of PAC transmission found support and were confirmed by metabarcoding. However, transmission via root contact was found to be the most successful. Growth of PAC through soil was also observed whereby transmission from PAC-colonized substrate to PAC-free saplings was more frequent than transmission from PAC-colonized to PAC-free saplings. The transmission rates depended on the PAC strain. Overall, we found support for vegetative transmission of PAC via root contact and active mycelial spread through semi-sterile soil.

Desertification-control policies have been applied in the Mu Us Desert since the 1950s. The landscape there is characterized by patches of shrub plants and well-developed lichen and moss crusts, some covered by shrub canopies and some in interspace soils. Little is known about how shrub cover and biocrusts shape soil fungal community structure in this ecosystem. Using high-throughput amplicon sequencing, the effects of biocrust types and shrub cover on soil fungal communities were analyzed. The results showed that biocrust types were more important than shrub cover in affecting soil properties and shaping soil fungal communities. Among all the measured soil properties, significant effects of shrub cover on soil pH and available P were observed. Biocrust types had significant effects on soil total organic carbon, C:N, and C:P ratios. Fungal taxa relating to plant pathogens and formation of lichens, (e.g., the Eurotiomycetes and Dothideomycetes and the of genera Endocarpon and Knufia) were dominant across biocrust types and shrub cover. Furthermore, although relative abundances of dominant fungal taxa were statistically similar among microhabitats, abundances of lichenized and pathogenic fungi differed significantly among biocrust types, with the former showing higher abundances in lichen crusts, and the latter exhibiting higher abundances in moss crosts. Soil total nitrogen and C:N were correlated with fungal community structure. Our results highligh the dominant role of biocrust types over shrub cover in shaping soil fungal communities in the Mu Us Desert. With the succession from lichen to moss crusts, increasing N limitation (soil TOC:TN ratio) may drive higher abundances of pathogenic fungi in lichen crusts and fewer lichenized fungi in moss crusts.

Host phylogenetic relatedness is the most widely accepted factor to explain host-fungus compatibility in ectomycorrhizal (ECM) fungi. The biogeographic similarity between host and fungus has been recently proposed as another important factor. However, as phylogenetically related hosts often have similar biogeography, it remains disputable whether host biogeography is an important determinant of host-fungus compatibility. In the present study, we conducted inoculation tests to evaluate the colonization ability of 13 ECM fungal operational taxonomic units (OTUs) which are putatively associated with Quercus serrata (Fagaceae), to three Japanese (Q. serrata, Castanopsis sieblodii [Fagaceae], and Pinus thunbergii [Pinaceae]) and two Australian species (Eucalyptus globulus and E. camaldulensis [Myrtaceae]). The colonization pattern of the inoculated OTUs could be classified into two categories: ECM fungi that associated only with Fagaceae and those associated with Japanese hosts. Eucalyptus was less able to associate with the inoculated fungi than P. thunbergii. Our results support the notion that the biogeographic similarity between fungi and hosts as well as host phylogeny can explain host-fungus compatibility.

Vegetation changes in a warming Arctic may affect plant-associated soil microbial communities with possible consequences for the biogeochemical cycling of carbon (C) and nitrogen (N). In a sub-arctic tundra heath, we factorially removed plant species with ecto- and ericoid mycorrhizal associations. After two years, we explored how mycorrhizal type-specific plant removal influences microbial communities, soil and microbial C and N pools, and extracellular enzymatic activities. Removal of ecto- and ericoid mycorrhizal plants did not change the soil fungal or bacterial community composition or their extracellular enzyme activities. However, ericoid plant removal decreased microbial C:N ratio, suggesting a stoichiometric effect decoupled from microbial community composition. In other words, microbial communities appear to show initial plasticity in response to major changes in tundra vegetation. This highlights the importance of longer-term perspectives when investigating the effects of vegetation changes on biogeochemical processes in Arctic ecosystems.

Fungal secondary metabolites (SMs) have attracted significant attention due to their pharmaceutical applications and negative impact as food contaminants. However, less attention has been paid to understanding the ecological role of SMs for the producer and their natural microbial community. To investigate this, we performed co-cultures of SM deficient mutant strains and wild type fungi isolated from mouldy windfall apples. The competitiveness of Penicillium expansum mutant strains was tested in co-cultures with Monilinia fructigena on apple puree agar. Remarkably, the absence of patulin production in P. expansum lead to a loss of antagonism against M. fructigena, revealing a nuanced ecological role that extends beyond the involvement of patulin in host pathogenicity. Furthermore, chemical analysis revealed biotransformation of patulin by M. fructigena, pointing to a more complex interplay mediated by SMs for fungal species inhabiting the same ecosystem.

Lichens are multi-kingdom symbioses in which fungi, algae and bacteria interact to develop a stable selection unit. In addition to the mycobiont forming the symbiosis, fungal communities associated with lichens represent the lichen mycobiota. Because lichen mycobiota diversity is still largely unknown, we aimed to characterize it in two cosmopolitan lichens, Rhizoplaca melanophthalma and Tephromela atra. The mycobiota were investigated across a broad distribution using both a culture-dependent approach and environmental DNA metabarcoding. The variation of the mycobiota associated with the two lichen species was extremely high, and a stable species-specific core mycobiota was not detected with the methods we applied. Most taxa were present in a low fraction of the samples, and no fungus was ubiquitously present in either lichen species. The mycobiota are thus composed of heterogeneous fungi, and some taxa are detectable only by culture-dependent approaches. We suspect that lichens act as niches in which these fungi may exploit thallus resources and only a few may establish more stable trophic relationships with the major symbiotic partners.