To investigate the resources, diversity and distribution of culturable mucoromycotan fungi in the Greater Khingan Mountains, 279 samples including dry branches and fallen leaves, humus, soil and faeces were collected from nine representative counties and cities. A total of 1,153 strains of mucoromycotan fungi were isolated using a dilution plate, cutting and direct incubation methods. Among the 1,153 strains, 706 representatives were analyzed on the basis of fungal molecular barcode ITS rDNA. These mucoromycotan fungi were classified into 3 orders, 8 families, 10 genera and 38 species. Dominant genera were Mortierella, Umbelopsis, and Mucor, while dominant species were Mortierella amoeboidea, Mucor hiemalis, and Umbelopsis isabellina. This paper also summarized all 26 genera of Mucoromycotina and Mortierellomycotina reported in China, and the distribution of the dominant genera and species of the Greater Khinggan Mountains were analyzed. In addition, regional distribution of all genera was analyzed with regard to three major ecological regions (Eastern wet and semi-humid ecological regions, northwestern arid and semi-arid ecological regions and the Tibetan Plateau alpine ecological regions). The results showed that nine genera were distributed in all the three regions. For endemic genera, nine were found in the Eastern wet and semi-humid ecological region, only one in northwestern arid and semi-arid ecological region, and none in the Tibetan Plateau alpine ecological regions.

The Greater and Lesser Khinggan Mountains of Northeast China is one of the important distribution areas of lichens in China, where is rich in lichen biodiversity. 259 lichen specimens deposited in herbariums and freshly-collected from 31 nature reserves, were examined comprehensively considering morphology, anatomy, chemistry and DNA sequences. We identified and reported 31 species belonging to 11 cetrarioid and hypogymnioid genera of Parmeliaceae in this paper, including 13 species of circumpolar element, 11 species endemic to East Asia, three cosmopolitan species, three species endemic to China, and one species of Eurasian element. A comparison with the previous records of distribution for lichens in the region shows that six species belonging to two genera were not rediscovered in current study, implying a great reduction or even a possible retreat of distribution for these lichens, especially two species endemic to Asia, i.e. Hypogymnia farinacea and H. nikkoensis, no additional specimen information has been added for more than 30 years since they were initially reported from the Greater and Lesser Khinggan Mountains as new record to China, and H. nikkoensis has been estimated to be Vulnerable (VU) in the recent red list assessment of Chinese macrofungi.

Aspergillus flavus is commonly regarded as a kind of saprophytic fungi with a wide distribution. It is the major aflatoxin B (AFB) and cyclopiazonic acid (CPA) producing species, as well as a pathogen to humans and animals. In the world, huge amounts of corns, peanuts and cotton seeds are vulnerable to be contaminated by A. flavus and aflatoxin each year. There is much variance in morphological, genetic and toxin-producing characters among isolates of A. flavus, resulting in its ambiguous population structure. In this paper, we analyzed 88 isolates of A. flavus from different environments of 26 provinces (including the Greater and Lesser Khinggan Mountains) in China, as well as nine ex-types and authentic strains based on CaM and benA sequences to infer their sequence types (STs) using multi-locus sequence typing (MLST), and their phylogenetic relationships and population structures employing MEGA 6.0 and Structure 2.3.4 softwares, together with their toxin-producing features (AFB and CPA). Our results showed that the 88 Chinese isolates and nine ex-type and authentic strains were distributed in three populations, i.e. A. flavus population I, A. flavus population II and population A. oryzae. There were 17 STs among the 97 isolates, among which the 88 strains from China were distributed in 15 STs. All isolates of population A. oryzae did not produce AFB, but most isolates of the A. flavus populations I and II produced AFB and CPA. The toxin-producing features were strain-specific, but not correlated to sequence types or populations. Some correlations between toxin-producing characters and geographical environments or crop types were recognized. The isolates of A. flavus populations I and II from the northeast areas planting corns, the arid northwest planting cottons and the south areas growing peanuts all produced AFB and CPA. The isolates from Hoh Xil of Qinghai and Aba of Sichuan did not produce AFB, though with the production of CPA. The isolates of A. oryzae population without AFB production were almost from North China with diverse climates and geographical environments, where the traditional Chinese soybean paste is made in the rural areas.

Russula fungi are widely distributed in the world, form ectomycorrhizae with plants, and play an important role in biodiversity maintenance and community assembly in forest ecosystems. The Greater and Lesser Khinggan Mountains of China are one of main areas in organism spreading from tropic to temperate areas in the biogeographical studies, but there are few studies on ectomycorrhizal fungi from this area. In this study, 96 specimens of Russula collected from the Greater and Lesser Khinggan Mountains were identified by the analysis of ITS sequences and morphological characters. The phylogenetic tree was reconstructed based on ITS sequences of 146 representative Russula species from China and other countries. The results showed that there were 46 taxa of Russula in the Greater and Lesser Khinggan Mountains, including 37 species and nine unidentified taxa. The analysis of geographical components of the 37 Russula species from the Greater and Lesser Khinggan Mountains showed that 13 species were north temperate, eight were temperate-tropical, nine were Eurasian, and seven were cosmopolitan. This study suggests that there are high species diversity of Russula, and their dominant components are clearly north temperate but also with some unique elements.

The species diversity and geographical component of Agarics and Boletus in the Greater and Lesser Khinggan Mountains were studied from 2014 to 2016. A total of 3,363 fungal specimens were collected and identified into 661 species belonging to 1 phylum, 4 classes, 18 orders, 61 families and 180 genera. Among them, 185 species were edible, 92 species were medicinal, and 110 species were poisonous. There were 16 dominant families (containing equal and more than 10 species), accounting for 27.87% of the total number of families, and 519 species accounting for 78.51% of the total number of all Agarics and Boletus species. There were 45 families(containing less than 10 species), with 142 species accounting for 21.48% of the total number of species. There were 29 dominant genera which contain equal and more than 5 species, accounting for 16.11% of the total number of genera, and 412 species accounting for 62.33% of the total number of species. In the respect of the floristic composition, this region was mainly composed of the species belonging to north temperate zone distribution, world-wide distribution and Eurasia continent distribution. Among them, 216 species were only distributed in the north temperate zone occupying 32.68% of all species, 167 species were world-wide distribution occupying 25.26% of all species, and 161 species were only distributed in the Eurasia continent occupying 24.36% of all species in the Greater and Lesser Khinggan mountains.

Lignicolous fungi, including dozens of butt-rot pathogenic fungi, are abundant in Northeast China. In the past decades, many investigations have been carried out on fungal species diversity, and thus plentiful species distribution data has been obtained. However, it is not clear whether there remains a region that has yet to be investigated for the presence of fungal species. In this study, four representative butt-rot pathogenic fungi, Fomitopsis pinicola, Porodaedalea laricis, Piptoporus betulinus and Trametes suaveolens, of Northeast China were selected. Their geographical distribution data and the correlating environmental factors were used to model their potential distribution using the maximum entropy model (MaxEnt). The area under the receiver operating characteristic curve (AUC) was examined to evaluate the model performance. Thus, the ecological niches of these species were analyzed. The results showed that all the species prediction models obtained high AUC values (0.990, 0.990, 0.989 and 0.967), which suggests that the prediction models were effective for the four species. The most effective environmental variables, which were the precipitation of warmest quarter (Bio18), the temperature annual range (Bio7) and the mean temperature of driest quarter (Bio9), were shown to contribute more to the species distribution models than other factors. The results delineate possible distribution ranges for the four pathogenic fungi in Northeast China, thereby offering forest managers a guide for where to focus prevention and treatment efforts for these pathogenic fungi.

Wood-decaying fungi decompose cellulose, semicellulose and lignin in wood by exuding various hydrolytic enzymes, so they play an important role in substance cycling in forest ecosystems. A field investigation to study these fungi was carried out in a permanent plot in the Fenglin National Nature Reserve. The wood-decaying fungal species, abundance and host wood characters were recorded. We analyzed the relationship between fungal diversity and the characters of the host wood, including species, abundance, degree of woody decay and wood diameter. A total of 295 specimens identified as 93 wood-decaying fungal species were recorded. The Shannon index was 3.86, and the Simpson index was 0.96. The species richness and abundance of wood-decaying fungi was significantly correlated with wood diameters of 2-5 cm and 5-10 cm, with a classification of 2 in degree of decay and with pine wood. The dominant hosts were Acer, Corylus, Picea and Pinus, and they each hosted different fungal communities. The dominant fungi in maple and hazelnut wood were Daedaleopsis tricolor, Trametes versicolor and Trichaptum pargamenum. Irpex lacteus, Trametes versicolor, Trichaptum abietinum and T. fuscoviolaceum were the dominant fungal species in pine and spruce wood. The analysis of the growing probability of fungal basidiocarps showed that the ratio of wood with basidiocarps to all dead wood of the same species plateaued in areas up to 0.36 ha. For example, the ratio of pine wood with basidiocarps to all pine wood was 10.2%, the ratio was 12.9% for maple wood, the ratio was 13.4% for spruce wood, and the ratio was 53.7% for hazelnut wood. These findings can help predict the occurrence of certain wood-decaying fungi in forest ecosystems.

Wood-decaying fungi have rich species diversity and play an important role in the decomposition of fallen wood in forest ecosystems. Conifer trees are dominant in the forest ecosystems of the Greater and Lesser Khinggan Mountains. Therefore, it is necessary to determine wood-decaying fungal species diversity in conifers and which factors influence their distribution in order to understand substance cycling in the forest ecosystems of the Greater and Lesser Khinggan Mountains. Over 16 years, 1,561 samples of wood-decaying fungi were collected from conifer trees (including Larix, Pinus, Abies and Picea) in the Greater and Lesser Khinggan Mountains. The host and fungal species and their rotting types were recorded, and the relationship between the fungal species distribution and potential influencing factors was analyzed. The results showed that there were 166 species belonging to 70 fungal genera found in the conifer wood of the Greater and Lesser Khinggan Mountains. This included 111 white-rot species (66.9%) and 55 brown-rot species (33.1%). Among the 166 fungal species, 19 species (11.5%) grew on all conifers. In the Greater Khinggan Mountains, larch was the dominant host, with the highest number of species and individuals of wood-decaying fungi found there. In contrast, pine was the dominant host in the Lesser Khinggan Mountains. This study of six typical sites showed that the biodiversity of wood-decaying fungi was higher in the Lesser Khinggan Mountains than the Greater Khinggan Mountains, with only 11 species occurring in all six sites. Further, the tree species had greater influence on the distribution of wood-decaying fungi than the site locations.

Myxomycetes are widely distributed in forest ecosystems and play an important role in nutrient cycling. The diversity and distribution of myxomycetes in two forests of the Lesser Khinggan Mountains, China were examined in Tangwanghexing’anshilin Forest Park and Shengshan National Nature Reserve. A total of 248 samples of myxomycetes were collected and identified to 44 species belonging to 17 genera of eight families in four orders based on morphological characteristics. Ten new species were recorded in Heilongjiang Province, such as Craterium dictyosporum, Physarum album and Reticularia splendens var. jurana. The species diversity of myxomycetes was higher in Tangwanghexing’anshilin Forest Park (36 species) than in Shengshan National Nature Reserve (25 species). Among the 44 species, 17 species were found in both sites and the composition similarity (C_S) was 55.7%. Physarum viride was the most dominant species in mixed coniferous and broad-leaved forests. Hemitrichia serpula was the most dominant species in Pinus koraiensis forest. This study suggests that vegetation type has an important influence on the species composition and diversity of myxomycetes.

As an important part of all microorganisms, bacteria play a vital role in the formation and decomposition of organic matter, the maintenance of ecosystem balance and the promotion of both animal and plant development. Here, the community structure and population diversity of culturable soil bacteria in the Greater and Lesser Khinggan Mountains were studied from 2014 to 2017 using the culture-dependent 16S rRNA sequencing method. Three thousand one hundred eighty bacterial strains were isolated from different habitats across 17 nature reserves in the Greater and Lesser Khinggan Mountains. Twenty-four genera and 120 species were identified from the specimens. Among them, Bacillus had the largest number of species and strains, 38 and 2,419, respectively. Bacillus was the dominant genus (76.1%) for this culture of bacteria from the Greater and Lesser Khinggan Mountains, followed by Brevisbasillus (13.0%). The species number, Simpson diversity index and Shannon-Wiener index were higher in the Greater Khinggan Mountains than the Lesser Khinggan Mountains. The subsequent analysis of the dominant genus of Bacillus showed that B. subtilis, B. thuringiensis and B. megaterium were important for the local economy and future scientific research.

Soil bacteria are important participants in the material cycling and energy flows in forest ecosystems. Therefore, the composition and biodiversity of bacterial communities are major indicators of soil ecological function. The aim of this study was to investigate the structure and diversity of bacterial communities across seven different habitats (i.e. Pinus koraiensis, Larix gmelinii, Quercus mongolica, Betula costata, coniferous-broad-leaved mixed forests, shrubs and meadows) in Da liangzihe National Forest Park by using high throughput sequencing technology. At the phylum level, the bacterial community composition was basically the same in all habitats, with Proteobacteria, Actinobacteria, Acidobacteria and Verrucomicrobia dominating the bacterial phyla by having relative abundance of more than 10%. At the genus level, 245 genera were identified, with 118 common genera accounting for 48.2% of all genera and 97.8% of the total relative abundance. The dominant genera, Spartobacteria_genera_incertae_sedis, Gaiella, Gp16 and Gp4, made up 47.0% of the total relative abundance. Spartobacteria_genera_incertae_sedis was the most abundant genus in every habitat. In addition, the soil bacterial diversity and the soil physicochemical factors differed significantly among the habitats. Both the diversity and richness of the soil bacterial community were higher in Pinus koraiensis than the other habitats. Soil pH was found to be a key factor affecting soil bacterial community diversity in Da Liangzihe National Forest Park.