With the rapid development of molecular biology and bioinformatics, next-generation sequencing technology can easily detect complex microbial taxa in different samples. Being faced with the analytical challenges by these complex and large amounts of microbiome data, it is a new research hotspot that core microbiome and keystone species of samples are described and analyzed by using the core microbiome methods in recent years. The obtainment can reveal the important microorganisms closely related to health, growth and production of the host, and contribute to the understanding of the relationship between microorganisms and hosts. Ultimately, these studies can help understanding the effects of microorganisms on the host, and the functions of microorganisms in natural ecosystems. This review describes the definition and research methods of core microbiome, the relationships between core microbiome and animals and plants, and provides suggestions to better utilize core microbiome for solving practical problems of environment, human health and agricultural production and so on.
Two green-ascospored new species, Trichoderma bomiense and T. viridicollare, are described and illustrated based on collections from Guangdong Province and Tibet Autonomous Region of China. Trichoderma bomiense collected at a high altitude has small brownish orange to greenish yellow or brown pulvinate stromata and trichoderma-like conidiophores. Trichoderma viridicollare is distinctive by its tiny pale yellow to pale green and pulvinate to turbinate stromata with very dark ostioles and greenish cortical tissues. Sequence analyses of the combined translation elongation factor 1-alpha and RNA polymerase II subunit B revealed that both fungi formed separate terminal lineages together with the clades of Trichoderma producing green ascospores.
Collections of Trichoderma from different regions of southern China were examined. Three Trichoderma species, T. neocrassum, T. pulvinatum, and T. samuelsii are new to China. Their morphological characteristics were described and illustrated based on the Chinese materials. The sexual states of T. ganodermatis, T. ingratum and T. trixiae are reported for the first time, and epitypes of the three names are designated. Phylogenetic positions of the above species were confirmed by sequence analyses combined of RNA polymerase II subunit b and translation elongation factor 1-alpha genes.
The gray-black moldy materials were collected on the wall of underground wine cellar and outer wall of the wine jar in Lujiu winery of Changzhi City of Shanxi Province, and the fungal pure cultures were obtained and purified in Czapek medium. The mycelium was observed by scanning electron microscope and stained by cotton blue with lactic acid carbonate. Based on 18S rDNA, β-tubulin gene and calmodulin gene sequence analysis, the isolated fungal were identified on molecular level. Three cultivable fungal species were idenified. The strain LJB-1 was identified as Racodium cellare, which hasn’t been reported so far in China. The strains LJ3-2 and LJ5-2 were identified as Penicillum spinulosum and Penicillium chrysogenum, and were rarely reported in liquor cellars.
The ectomycorrhizal(ECM) fungal community composition in the root zone soilof Larix gmelinii var. principis-rupprechtii in Inner Mongolia was investigated, and the effect of soil physicochemical properties on the community was explored. Daoxugou and Dabagou of Heilihe National Nature Reserve, and Nansi of Helanshan National Nature Reserve were selected as sample plots. DNA ITS1 region of the fungi in root zone soil were sequenced using the Illumina MiSeq High-throughput sequencing platform. A total of 65 859 sequences of ECM fungi obtained, were divided into 436 OTUs which belong to two phyla, six classes, 12 orders, 26 families and 41 genera, being mainly distributed in Basidiomycota. The dominant ECM fungal OTUs totalled 17, belonging to Russula,Cortinarius,Amphinema,Piloderma,Clavulina,Inocybe,Cenococcum,Tomentella and Meliniomyces. The fungal community composition in Daoxugou and Dabagou of Heilihe National Nature Reserve are similar. The heatmap indicates both localities are similar in composition at genus level. PerMANOVA shows that the difference of composition between the two localities is not significant. However, ECM fungal community composition in the both localities is significantly different from that in Nansi of Helanshan National Nature Reserve (P=0.0234), and the diversity and abundance of dominant ECM fungi are lower than those in Nansi. The synergetic effect of soil physicochemical propertiesTP and pH has significant relation (P=0.0383)to ECM fungal community composition, showing positive effect on the ECM fungi community of L. gmelinii var. principis-rupprechti in Nansi, and negative effect on that in Daoxugou and Dabagou.
Six different kinds of culture media are used to isolate and cultivate the fungi associated with the South China Sea sponge. The isolates obtained totaled 55, belonging to 22 species. The identification was made through morphological observation in combination with ITS-rDNA blast homology analysis. The dominant genus is Trichoderma (31 isolates), and Trichoderma harzianum is dominant species (22 isolates), accounting for 40% of the total number of isolates. The remainder belongs to Cladosporium, Meyerozyma, Rhodotorula, Microsphaeropsis, Penicillium, Aspergillus, Phoma, Candida, Pestalotiopsis, and Engyodontium. Besides, two ascomycete isolates are unidentified. Seven indicator bacteria including Staphylococcus aureus were selected for antibacterial activity test. By using agar diffusion method, the bacteriostatic effect of the fungal isolates was verified. The result demonstrated that three isolates showed antibacterial activity for at least an indicator bacteria.
The impact method was used to collect airborne fungi in dry and rainy seasons for 4 times in different experimental sites (fields, sheds and storehouse) of the Xishuangbanna Tropical Rainforest Atmospheric Experiment Station. The quantity of fungi was calculated using a statistical method at different experimental sites in dry and rainy seasons. The fungal strains were identifiedby morphological characters combined with ITS1-5.8S-TIS2 or 26S rDNA D1/D2 region sequence analysis. The relationship between environmental factors and atmospheric fungi was preliminarily investigated using the SPSS and R software. The results showed that the concentration of airborne fungi was 2 200-4 300cfu/m 3 in the atmosphere of Xishuangbanna ExperimentStation, and 776 strains of fungi were isolated and classified into 34 genera and 52 species. The dominant species were Aspergillusminisclerotigenes,Cladosporiumoxysporum, Clonostachysepichloe, Fusariumincarnatum, Leptosphaerulinachartarum,Paraconiothyriumestuarinum andPenicilliumsteckii. The fungal diversity in the atmospheric environment is rich but the communities and concentrations of fungi changed seasonally. The community structure of fungi varied significantly among the three experimental sites in different seasons. The important environmental factors which affected the structure of airborne fungal community were precipitation and atmospheric pressure.
Trichothecium roseum is an important pathogen of various crops. Protoplasts of T. roseum were obtained via digesting cell walls of young hyphae by use of enzymatic solutions, and exogenous plasmid DNA carrying GFP gene and zeocin resistant gene was inserted into T. roseum genome by PEG mediated protoplast transformation. Totally 90 transformants were obtained from zeocin resistant screening plates, and DNA transformation efficiency reached 18 protoplasts/μg. Twenty-two transformants were used for observing fluorescence signals. Transformants showed green fluorescent signals on various fluorescent intensities depended on transformant individuals, and ten of them displayed relatively stronger fluorescent signals. There was no difference of biological characteristics including colonial morphology, conidiation as well as pathogenicity between the representative transformant TR45 and the wild type strain. As for transformant TR45 the green fluorescence was still stable after subculturing ten generations on plates without zeocin stress. The protocols of efficient protoplast preparation and PEG mediated protoplast transformation used in this study could be applied to explore functional genes of T. roseum. The obtained GFP tagged strains could be used for further researches on pathogen penetration, field detection and infection cycles of related diseases caused by T. roseum.
The lignin-degrading enzymes (LDEs) of Pleurotus ostreatusplay a key role in lignin degradation. In this study, P. ostreatus New 381 strain was chosen as the experimental material. The effects of different manganese ion [Mn(II)] concentrations on the mycelial growth, degradation rate of azo-dye Orange II, LEDs activities and primordium formation were studied through the methods of solid agar culture and liquid culture. Addition of Mn(II) could promote mycelium growth.The optimum Mn(II) concentration of GP-Orange liquid culture was 50μmol/L, and that of GP-Urea-Orange solid agar culture was 70μmol/L. The Orange II degradation was accelerated by Mn(II), and the highest degradation rate and the largest decolorized area were all obtained at 70μmol/L Mn(II). The activities of laccase (Lac) and manganese peroxidase (MnP) increased first and then decreased with increasing Mn(II) concentration, while the lignin peroxidase (LiP) activity reduced with increasing Mn(II) concentration. Addition of Mn(II) could induce primordium formation, and the largest primordia were formed at 70μmol/L Mn(II). The result of plate culture experiment also indicates that there is no correlation between LEDs activities and mycelial biomass, and LEDs are mainly expressed under nutrient limitation.
The functionary mechanism of arbuscular mycorrhizal (AM) fungi on the growth and lengthening the ornamental period of Lilium brownii post-harvest cut flowers in vase was investigated. The lily plants were inoculated with AM fungi Funneliformis mosseae, Glomus versiforme and F. mosseae+G. versiforme (Fm+Gv) under greenhouse pot culturing conditions. The results showed that Fm+Gv inoculation resulted in the increase of dry weight of ground part and root of the plants, reaching 60% and 58% respectively as compared with the uninoculated control. The tip number, length, branching number, surface area and volume of lily root increased by 123%, 128%, 182%, 118% and 232% respectively over the uninoculated control. The water balance and fresh weight change rate of lily cut flowers with AM fungal treatment were significantly higher than those of the control, and the release rate and respiration rate of ethylene significantly decreased, reached the peak of 5.4μL/[g·h (FW)] at day 5. Compared with the control, the ethylene release rate of lily cut flowers treated with Fm+Gv was decreased by 30%, and respiratory rate reached up to 0.7μL/[g·h(FW)] in 1d, 37% lower as compared with the control. The superoxide dismutase (SOD) activity in lily petals increased by 19%, and the catalase (CAT) activity increased by 32%; the soluble sugar content increased by 52% and the soluble protein content increased by 26%. The content of N, P, K, Mg, Ca, Fe and Zn in the flaps were significantly higher than that in the flaps of non-inoculation treatment, while the content of Mn and Cr was lower than that in the control. The vase life of lily prolonged for three days, and the best viewing period two days or longer. The conclusion is that the simultaneous inoculation treatment of F. mosseae+G. versiforme can effectively improve the water balance, nutritional status and physiological metabolism of cut flower branches, control the synthesis of senescence hormone and prolong the life and viewing period of lily cut flower.
The photosensitive toxic symptom caused by Bulgaria inquinans puzzled local residents of Changbai mountainous area all along. Eating the fungus without alkali treatment can cause swelling of mouth and burning pains of skin when exposure under sunlight. The study aimed at finding the photosensitive toxic components of B. inquinans. The active extract was obtained from B. inquinans fruiting bodies, using as dissolvent acetone. The extract was administrated to mice, and then the active component was further obtained from the methanol extract of mice’s red swelling ears. The active compound was identified as diisobutyl phthalate (DiBP) by using 1H-NMR and 13C-NMR, and EI-MS spectroscopy. DiBP was proved to be the photosensitive toxic compound of B. inquinans causing photosensitivity of mice. DiBP can be degraded in alkaline water and the toxicity can be decreased.
The chemical composition and anti-tumour active compound of Inonotus hispidus were studied. Liquid-liquid distribution using petroleum ether, ethyl acetate, and n-butanol was adopted for extraction of methanol extract of Inonotus hispidus fruiting body. Sephadex LH-20 gel chromatography, reversed-phase C18 column chromatography and high performance liquid chromatography (HPLC) methods were used for further separation and purification of the extract. Eight compounds were isolated and identified, viz. ergosterol, eburicoic acid, (E)-4-(3,4-dihydroxyphenyl) but-3-en-2-one, phellibaumin A, 3,3’-methylene-bis[6-(3,4-dihydroxystyryl)-4-hydroxy-2H-pyran-2-one] (MBP), inosine, protocatechuic acid and protocatechualdehyde. MBP was purified from nature for the first time, and it was used for MTT anti-tumour screening and apoptosis analysis. It was proved that MBP could inhibit the proliferation of HepG2 cells, with half-maximal inhibitory concentration of 2.3μg/mL, and it could induce HepG2 cell apoptosis in a dose-dependent manner.
By using α-glucosidase enzyme model in vitro, the inhibitory activity of ethyl acetate extract from mycelium and culture of Chaetomium globosum H6 on α-glucosidase enzyme was evaluated. The results showed that ethyl acetate extract of the culture had strong inhibitory activity with IC50 value of (510.76±23.46)μg/mL. Twelve compounds were isolated by chromatographic technologies such as silica gel, Sephadex LH-20 and preparative HPLC. Chemical structures of compounds were identified as chaetoviridins A-B (1-2), chaetoglobosins A-D (3-6), chaetoglobosin J (7), chaetoglobosin Q (8), prochaetogobosins I-III (9-11), vibratilicin (12) by analysis of the spectroscopic data. Among them, compound 12 was isolated from Chaetomium for the first time. The inhibitory activity of α-glucosidase enzyme of the above-mentioned compounds was evaluated. Compound 12 displayed weak activity with IC50 value at (1 182.75±19.14)μg/mL.
