To determine the diversity of arbuscular mycorrhizal fungi (AMF) in the rhizosphere soil of Taxus chinensis, 12 different sites were sampled in China. A total of 36 species of AMF belonging to three genera were identified according to the morphological characteristics of the spores isolated from soil samples. In these species, 13 belonged to Acaulospora, 20 Glomus and 3 Scutellospora, respectively accounting for 36.1%, 55.6% and 8.3% of the total. Acaulospora and Glomus were distributed in all of the 12 sampling sites, but Scutellospora was only found in Zhejiang-1, Zhejiang-3 and Zhejiang-5. A. cavernata and A. laevis were dominant species. The average AMF spore density was 242 per 50g air-dried soil, ranging from 33 to 925. The average species richness was 10.3. The richness in Yunnan was the highest, and that in Guangdong the lowest. Shannon-Wiener index and Simpson index ranged respectively from 1.12 to 2.55 and 0.57 to 0.91. Root infection rate ranged from 18%-82% and the infection level was 2-5. The content of total glomalin (T-GRSP) and easily extractable glomalin (EE-GRSP) in natural forest was higher than that in artificial forest, in general.
Polyporus umbellatus and Gastrodia elata are traditional Chinese herb medicine, having high medicinal value. Both P. umbellatus and G. elata depend on Armillaria spp. supplying necessary nutrition for their growth. Correlations between Armillaria and P. umbellatus, and Armillaria and G. elata are still imperfectly known. In this research, based on the collected sclerotial samples from 11 provinces in China, 47 Armillaria strains were isolated and their sequences of ITS, β-tubulin and elongation factor-1 alpha gene were obtained. These sequences together with Armillaria sequences associated with G. elata reported in literature were compared. Phylogenetic analyses indicated that ten clades of Armillaria could be classified in total, and six and seven of them are associates with P. umbellatus and G. elata respectively. Three clades are shared by P. umbellatus and G. elata, and they mainly include the strains from Shaanxi, Shanxi, Jilin, Heilongjiang, Guizhou, Gansu and Sichuan. The strains from Yunnan and Tibet are of highly specificity. Our results elucidate the differences and similarities of Armillaria partners between P. umbellatus and cultivated G. elata through phylogenetic aspect, and provide important theoretical support for the selection of Armillaria species in cultivation of P. umbellatus and G. elata.
A fungal isolate 6222-1 was generated from the imported sorghum seeds shipped from America. It was morphologically similar to Colletotrichum sublineola producing falcate or fusiform conidia and hyphopodial appressoria on PDA medium. The multi-locus (ITS, GAPDH, CHS-1, HIS3, ACT and TUB2) phylogenetic analysis revealed that the isolate was clustered within the type strain of C. sublineola. The pathogenicity test revealed that it infected sorghum leaves by forming typical anthracnose symptom. Based on the above results the isolate was identified as C. sublineola. This is the first interception report of C. sublineola from the imported American sorghum seeds by Chinese quarantine agency.
This paper includes three aspects. First, a new concept of classification has been proposed, i.e. systematic biology of lichenized fungi with three systems of storage and retrieval is a bridge between biodiversity in the nature and exploration of lichen resources. Second, the symplesiomorphic analyses based on genotype together with phenotype data have solved the generic classification in the Umbilicariaceae, which has not been solved by the analyses of molecular systematics. Third, marginal species have been found in genus differentiation of the Umbilicariaceae by symplesiomorphic analyses. The concept of the marginal species is discussed. The results show, the family Umbilicariaceae and their genera are monophyletic group respectively.
The anamorphic state of Ophiocordyceps xuefengensis, a recently described species of Ophiocordyceps associated with larvae of Phassus nodus (Hepialidae) in living root or trunk of Clerodendrum cyrtophyllum, was isolated from the stroma of the fungus. Cultural and morphological characteristics, as well as molecular evidence (ITS sequence) have proved its identity. The mating-type gene MAT1-2 was amplified by polymerase chain reaction (PCR), however, MAT1-1 gene was not determined. The fungus bearing stroma was cultivated successfully in artificial media.
The fungal lectins have many biological functions, such as regulating the growth and development, stress tolerance, antitumor, etc. Yet, the functions of lectin genes in response to various biotic and abiotic stress in Pleurotus ostreatus are poorly understood. In this study, cloning and functional identification of polectin2 gene and its promoter polectinpro from the fruiting body of P. ostreatus are carried out. The sequencing and bioinformatics analysis indicate that the promoter and cDNA of polectin2 are 927bp and 408bp respectively, encoding 136 amino acids without intron. The molecular weight of lectin2 is 15.3kDa using the prediction by PLACE. The results obtained by PLACE database analysis indicated that the nucleotide sequence of polectinpro contained multi regulatory elements, such as regulating the functional genes responding to low temperature, drought and pathogens. GFP fusion expression vector of pCAMBIA1302-polectinpro-gfp and the recombinant expression vector of pCAMBIA1301-lectin2 were constructed, and transformation to tobacco was conducted. The results showed that the gfp gene was fusion-expressed in the transgenic plants, indicating this promoter could induce by cold stress. It was revealed that T0 and T1 transgenic plants contained the exogenous gene polectin2, and the germination rate of T1 transgenic seeds under cold stress was higher than that of the wild type of tobacco. The results suggest the lectin2 gene from the fruiting body of P. ostreatus could resist cold stress. Our study will provide the new gene resource for further breeding edible mushroom against abiotic stress.
Aldehyde dehydrogenase gene PoALDH1 and its full-length cDNA sequence were cloned from Pleurotus ostreatus. The PoALDH1 is 2 016bp encoding a putative protein of 478 amino acids. The amino acid sequence contains conservative glutamic acid and cysteine residue active sites of aldehyde dehydrogenase family. The measurement of aldehyde dehydrogenase activity and aldehyde tolerance by PoALDH1 gene expressing in Escherichia coli showed that ALDH specific activity of the recombinant strain was 0.58U/mg and acetalde tolerance of recombinant strain was significantly higher than that of control strain. The analysis of PoALDH1 differential expression between dicaryotic mycelium stage and primordial stage through quantitative real-time PCR (qRT-PCR) showed that the expression level in primordial stage was about four times higher than that in dicaryotic mycelium stage. The analysis of PoALDH1 differential expression under the stress of light or low temperature during primordial formation showed that PoALDH1 was significantly up-regulated. When exposed to different concentrations of sodium chloride or mannitol, the mycelial growth was inhibited and the expression level of PoALDH1 was significantly higher than that of the control ones. The research results will lay the foundation for both the further exploration of the stress resistant mechanism of Pleurotus ostreatus and the development of edible fungi at molecular level.
Characterization of cold-adapted cellulase produced by Scopulariopsis hibernica E71702M was analyzed preliminarily, and optimum conditions of cellulase production were obtained by response surface methodology. The effect of temperature, pH and metal ions on cellulase activity was determined by single factor test. The important factors influencing cellulase production, as identified by a two-level Plackett-Burman design with eight variables, were wheat bran content, liquid volume, and initial pH. The Box-Benhnken design and response surface analysis were adopted to further investigate the mutual interactions between these variables and to obtain their optimal values that bring maximum cellulase activity. The research results of cold-adapted cellulase characterization revealed that the optimum pH was 3.0 and the reaction temperature was 30°C. The remaining cellulase activity at 0°C still reached 56.3% as compared with that at optimal reaction temperature. The optimal conditions of the maximal cellulase activity were indicated as follows: wheat bran content, 8.79g/L; liquid volume, 40.93mL; initial pH value, 4.01. Under the conditions, cellulase activity was increased by 174%, ranging from 0.6338 to 1.7386IU/mL.
The influence of key factors on flavonoid synthesis of Sanghuangporus sanghuang was investigated. Based on the single-factor experiment of the addition of magnesium acetate, the three factors having significant effects on flavonoid production, inoculation amount, the addition of magnesium acetate and glucose in substrate, were screened out by using Plackett-Burman design. The results of the central composite design showed that the optimal levels of the main factors were: nutritional factors in the culture medium included glucose 23.41g/L, yeast extract 10g/L, mulberry powder 10g/L, KH2PO4 1g/L, and MgSO4·7H2O 1g/L, inoculation amount of 10%, and magnesium acetate content of 1.16g/L. The yield of flavonoids reached 0.7453g/L under the optimal fermentation condition, and increased by 1.43 times as compared with that of initial medium. Moreover, the results showed that the flavonoid production was greatly improved by adding magnesium acetate in liquid fermentation of Sanghuangporus sanghuang, providing a valuable reference for the flavonoid production on a larger-scale.
The non-enzymatic protein glycosylation (NEPG) is one of the main factors causing diabetes complication, therefore it played a significant role to explore natural active substances inhibiting NEPG reaction. In this study, using metformin as positive control, the inhibitory effects of alcohol extracts and water extracts from six mushrooms including Grifola frondosa, Tremella fuciformis, Auricularia heimuer, Coprinus comatus, Hericium erinaceus and Wolfiporia cocos on NEPG in vitro were compared. The experiment results showed that the water extract from G. frondosa held highest inhibitory activity on NEPG reaction. The alcohol extracts from six mushrooms could not inhibit NEPG reaction in vitro. The extracting conditions of G. frondosa active substances were optimized by quadratic rotation-orthogonal combination design. The optimal extracting temperature and duration for G. frondosa active substances were 85°C and 2.25h, respectively. The optimal ratio of material to liquid was 1:30. Under these optimal extracting conditions, the inhibitory rate of the extract on NEPG reaction was (96.28±0.16)%, indicating that the water extract of G. frondosa had good prospects in the prevention of diabetes complication.
Three new records of Cercospora and Pseudocetcospora from China are reported. They are Cercospora insulana on Limonium sinuatum, Pseudocercospora kurimensis and P. repens on Nerium indicum. Illustrated descriptions are provided. Examined specimens are deposited in HMAS.
During making a survey of Hebeloma collections from Inner Mongolia Autonomous Region and Jilin Province, three species, namely H. alpinum, H. dunense and H. leucosarx, were found to be unrecorded previously in China. Morphological characters of the three species were described, together with line drawings, SEM images of spores, and ITS sequence for each species. Phylogenetic analysis based on ITS nucleotide sequences supported our morphology-based taxonomy.
