The Diverse Mycorrizal Morphology of Rhododendron dauricum, the Fungal Communities Structure and Dynamics from the Mycorrhizosphere.

It is generally believed that mycorrhiza is a microecosystem composed of mycorrhizal fungi, host plants and other microscopic organisms. The mycorrhiza of Rhododendron dauricum is more complex and the diverse morphology of our investigated results displays both typical ericoid mycorrhizal characteristics and ectomycorrhizal traits. The characteristics of ectendoomycorrhiza, where mycelial invade from the outside into the root cells, have also been observed. In order to further clarify the mycorrhizal fungi members and other fungal communities of R. dauricum mycorrhiza, and explore the effects of vegetation and soil biological factors on their community structure, we selected two woodlands in the northeast of China as samples-one is a mixed forest of R. dauricum and Quercus mongolica, and the other a mixed forest of R. dauricum, Q. mongolica, and Pinus densiflor. The sampling time was during the local growing season, from June to September. High-throughput sequencing yielded a total of 3020 fungal amplicon sequence variants (ASVs), which were based on sequencing of the internal transcribed spacer ribosomal RNA (ITS rRNA) via the Illumina NovaSeq platform. In the different habitats of R. dauricum, there are differences in the diversity of fungi obtained from mycorrhizal niches, and specifically the mycorrhizal fungal community structure in the complex vegetation of mixed forests, where R. dauricum is found, exhibits greater stability, with relatively minor changes over time. Soil fungi are identified as the primary source of fungi within the mycorrhizal niche, and the abundance of mycorrhizal fungi from mycorrhizal niches in R. dauricum is significantly influenced by soil pH, organic matter, and available nitrogen. The relationship between soil fungi and mycorrhizal fungi from mycorrhizal niches is simultaneously found to be intricate, while the genus Hydnellum emerges as a central genus among mycorrhizal fungi from mycorrhizal niches. However, there is currently a substantial gap in the foundational research of this genus, including the fact that mycorrhizal fungi from mycorrhizal niches have, compared to fungi present in the soil, proven to be more sensitive to changes in soil moisture.

Response of bacterial community structure to different ecological niches and their functions in Korean pine forests.

A healthy plant microbiome is diverse, taxonomically-structured, and gives its plant host moderate advantages in growth, development, stress tolerance, and disease resistance. The plant microbiome varies with ecological niches and is influenced by variables that are complex and difficult to separate from each other, such as the plant species, soil, and environmental factors. To explore the composition, diversity, and functions of the bacterial community of Korean pine forests, we used high-throughput sequencing to study five areas with different forest ages from June to October 2017 in northeast China. We obtained 3,247 operational taxonomic units (OTUs) based on 16S rRNA gene sequencing via an Illumina Hi-seq platform. A total of 36 phyla and 159 known genera were classified. The Shannon index of the bacterial community from the rhizospheric soil was significantly higher (p < 0.01, n = 10) than that of the root tips. Beta-diversity analysis confirmed that the bacterial community of the rhizospheric soil was significantly different (p < 0.001) from the root tips. Nine bacterial phyla were dominant (relative richness > 1%) in the rhizospheric soil, but there were six dominant phyla in the root tips. Proteobacteria was the core flora in the root tips with a relative abundance of more than 50%. It is known that the formation of bacterial communities in the rhizospheric soil or the root is mainly caused by the processes of selection, and we found a relatively high abundance of a few dominant species. We further analyzed the correlations between the bacterial community from the rhizospheric soil with that of the root tips, as well as the correlations of the bacterial community with soil physicochemical properties and climate factors. We used Functional Annotation of the Prokaryotic Tax (FAPROTAX) to predict the functions of the bacterial community in the rhizospheric soil and root tips. Five related phototrophic functions, nine nitrogen cycle functions, two related chemoheterotrophic functions, and two others were predicted. The abundance of the bacteria phyla performing relevant functions was different in the rhizospheric soil than in the root tips. These functions were significantly influenced by the contents of nitrogen, phosphorus, and potassium in the soil habitat. The bacterial composition and functions in the rhizospheric soil and root tips of Korean pine were analyzed, and the results demonstrated the importance of soil and plant species on the bacterial community in the below ground plant microbiome.

Fungal-Bacterial Networks in the Habitat of SongRong (Tricholoma matsutake) and Driving Factors of Their Distribution Rules.

Soil origin, mycorrhizal plant partners and environmental factors affect the growth and development of SongRong (Tricholoma matsutake). In order to clarify the relationships of fungi-bacteria networks and various influence factors in the habitat of SongRong, we chose three collection sites with a Quercus mongolica pure forest (plot A without SongRong was used as the control sample site), Q. mongolica mixed Rhododendron dauricum (plot B) and Q. mongolica mixed with R. dauricum and Pinus densiflora (plot C). By using high-throughput sequencing, we obtained a total of 4930 fungal and 55501 bacterial amplicon sequence variants (ASVs) based on internally transcribed spacer ribosomal RNA (ITS rRNA) and 16S ribosomal RNA (16S rRNA) sequencing via the Illumina NovaSeq platform. In the habitat soil of SongRong (plot B and plot C), alpha or beta diversity and species compositions of fungi and bacteria were different from plot A. The fungal-bacterial networks follow the selection rule that few dominant genera account for the greater relative abundance. Forest types, but not the host itself, drove the fungal-bacterial networks of the forest soil, and soil physicochemical characteristics and texture affected their abundance. The abundance of Tricholoma was affected by the fungal and bacterial abundance in the habitat.

Morphological and Phylogenetic Evidence Reveal Five New Telamonioid Species of Cortinarius (Agaricales) from East Asia.

Five new Cortinarius species, C. neobalaustinus, C. pseudocamphoratus, C. subnymphatus, C. wuliangshanensis and C. yanjiensis spp. nov., are proposed based on a combination of morphological and molecular evidence. Cortinarius neobalaustinus is characterized by a very weakly hygrophanous and yellowish-brown to brown pileus and small and weakly verrucose basidiospores. Cortinarius pseudocamphoratus can be characterized by a viscid pileus, a strongly unpleasant smell, amygdaloid to somewhat ellipsoid basidiospores and lageniform to subfusiform cheilocystidia. Cortinarius subnymphatus is identified by a strongly hygrophanous pileus that is reddish-brown with a black-brown umbo, a yellowish universal veil and ellipsoid to subamygdaloid basidiospores. Cortinarius wuliangshanensis is characterized by a moderately to strongly hygrophanous, translucently striated and yellowish to reddish-brown pileus and rather weakly and moderately verrucose basidiospores. Cortinarius yanjiensis is distinguished by a weakly to moderately hygrophanous and yellowish to brown pileus and moderately to rather strongly verrucose basidiospores. The phylogenetic analyses were performed with maximum likelihood and Bayesian inference methods based on the data set of nuc rDNA ITS1-5.8S-ITS2 (ITS), D1-D2 domains of nuc 28S rDNA (28S) and RNA polymerase II second largest subunit (rpb2), and the results show that C. neobalaustinus, C. wulianghsanensis and C. yanjiensis cluster in sect. Illumini, C. pseudocamporatus belongs to sect. Camphorati and C. subnymphatus belongs to sect. Laeti. In addition, a study of basidiospores under field emission scanning electron microscopy (FESEM) was conducted. An identification key for the five new species and related species from China is also provided.

Cortinarius subsalor and C. tibeticisalor spp. nov., two new species from the section Delibuti from China.

Cortinarius subsalor and C. tibeticisalor, belonging to the section Delibuti, are described from China as new to science. Cortinarius subsalor has been found to be associated with Lithocarpus trees in subtropical China and resembling C. salor, but it differs from the later by having slender basidiomata and the narrower basidiospores. Cortinarius tibeticisalor was collected from eastern Tibetan Plateau, associated with Abies. It differs from other species within sect. Delibuti by having olive tinge of mature or dried basidiomata and bigger basidiospores. The molecular data also support C. subsalor and C. tibeticisalor as new species. The phylogenetic analyses and biogeography of sect. Delibuti are discussed and a key to the species of this section currently known in the world is provided.

Three new species of Cortinarius subgenus Telamonia (Cortinariaceae, Agaricales) from China.

Cortinarius is an important ectomycorrhizal genus that forms a symbiotic relationship with certain trees, shrubs and herbs. Recently, we began studying Cortinarius in China and here we describe three new species of Cortinarius subg. Telamonia based on morphological and ecological characteristics, together with phylogenetic analyses. Cortinarius laccariphyllus sp. nov. (section Colymbadini) is associated with broadleaf trees, with strongly hygrophanous basidiomata, special Laccaria-like lamellae and white and extremely sparse universal veil. Cortinarius neotorvus sp. nov. (section Telamonia) is associated with broadleaf trees and is easily confused with C. torvus, but can be distinguished by the colour of the fresh basidiomes and the stipe usually somewhat tapering towards the base. Cortinarius subfuscoperonatus sp. nov. (section Fuscoperonati) is associated with coniferous trees, with subglobose to broadly ellipsoid spores and is closely related to C. fuscoperonatus. A key to the new species and similar species in sections Colymbadini, Telamonia and Fuscoperonati is provided.

[Effect of ectomycorrhizal fungi on the seedlings growth of Korea spruce].

To enhance the effects of ectomycorrhizal fungi to promote the growth of Korea spruce seedlings, based on previous research, the combinations of different ectomycorrhizal fungi strains were screened by dual culture method. 3 years transplanting seedlings of Korea spruce were inoculated by different combinations of ectomycorrhizal fungi strains using lister inoculating method in the field, and those were inoculated by different single strains were designed as control respectively. Thus the effects of different combinations and different single fungus strains to promote the growth of Korea spruces were studied. The results showed that all single strains and combinations in this experiment can promote the growth of Korea spruce seedlings. The growth characteristics of seedlings were observed 100 days after inoculation. The growth promoting effect of strain L15 was the best in all combinations and single strains. Comparing with control, the average height of seedlings inoculated by strain L15 was increased 30.88%, the average collar diameter of these was increased 15.29%. The growth promoting effect of combinations L15/025 or L15/009 were better than strain 009 or 025. Comparing with control, the leaf chlorophyll contents of seedling inoculated by strain 010 and combination L15/025 were increased significantly, the contents of chlorophyll a were increased 59.15% and 54.61% respectively, and the contents of chlorophyll b were increased 76.34% and 67.78% respectively. Except seedling inoculated by strain 010, the activities of hydrogen peroxidase of other treated seedlings were lower than one of control. The root activities of all treated seedlings were lower than one of control. In conclusion, inoculation by the mixture of high-effect strain and other single strain weakens the effect of high-effect strain to promote the growth of Korea spruce seedlings, the activity of hydrogen peroxidase and the root activity of seedling are not correlated with its biomass.