Comparison of endogenetic microbial community diversity between wild Cordyceps sinensis,artificial C. sinensis and habitat soil / 中国中药杂志

To obtain the difference of the fungal and bacterial community diversity between wild Cordyceps sinensis, artificial C. sinensis and their habitat soil, Illmina Hiseq high-throughput sequencing technology was applied. The results show that Proteobacteria was the dominant bacterial phylum in C. sinensis, Actinobacteria was the dominant bacterial phylum in soil microhabitat, Ophiocordyceps sinensis was the predominant dominant fungus of C. sinensis. The α diversity analysis showed that the fungal diversity of stroma was lower than other parts, and the fungal diversity of wild C. sinensis was lower than that of artificial C. sinensis. The β diversity analysis showed that the fungal and bacterial community diversity of soil microhabitat samples was significantly different from that of C. sinensis. The fungal community diversity was less different between wild and artificial C. sinensis, especially in sclerotia. LEfSe analysis showed a lot of species diversity between wild and artificial C. sinensis. Those different species between wild C. sinensis, artificial C. sinensis and their habitat soil provide ideas for further research on breed and components of C. sinensis.

Overexpression of ribonucleotide reductase small subunit, RNRM, increases cordycepin biosynthesis in transformed Cordyceps militaris / 中国天然药物

Cordycepin was the first adenosine analogue used as an anticancer and antiviral agent, which is extracted from Cordyceps militaris and hasn't been biosynthesized until now. This study was first conducted to verify the role of ribonucleotide reductases (RNRs, the two RNR subunits, RNRL and RNRM) in the biosynthesis of cordycepin by over expressing RNRs genes in transformed C. militaris. Quantitative real-time PCR (qRT-PCR) and western blotting results showed that the mRNA and protein levels of RNR subunit genes were significantly upregulated in transformant C. militaris strains compared to the control strain. The results of the HPLC assay indicated that the cordycepin was significantly higher in the C. militaris transformants carrying RNRM than in the wild-type strain, whereas the RNRML was preferentially downregulated. For the C. militaris transformant carrying RNRL, the content of cordycepin wasn't remarkably changed. Furthermore, we revealed that inhibiting RNRs with Triapine (3-AP) almost abrogated the upregulation of cordycepin. Therefore, our results suggested that RNRM can probably directly participate in cordycepin biosynthesis by hydrolyzing adenosine, which is useful for improving cordycepin synthesis and helps to satisfy the commercial demand of cordycepin in the field of medicine.

SSR loci information analysis in transcriptome of Cordyceps sinensis / 中国中药杂志

To analysis the SSR loci information in the transcriptome of Cordyceps sinensis and develop SSR molecular markers,MISA(MicroSatellite) software was used to analyze the microsatellites information from 16 875 unigene sequences and SSR primer designed by Primer 3. 0. In total,5 899 SSRs were detected in 4 252 unigene with the distribution frequency of 34. 99%,which was represented by 74 repeat motifs and SSR loci occurred per 7 952 bp in length. In the SSRs,the mono-nucleotide was the most abundant repeat motif(42. 5%),followed by tri-nucleotide(34. 48%),C/G and CCG/CGG were the dominant repeat motifs,respectively. The number of repetitions of the six SSR repeat types was concentrated on 5 to 12 times,and the length was mostly less than 24 bp. A total of 12 282 pairs of primers were screened and selected 20 pairs of primers for validity detection randomly,10 pairs of primers amplified the expected specific bands,and primer P1 has significant polymorphism. Moreover,it was found that unigene containing SSR loci is mainly related to genetic and environmental functions after GO and KEGG annotation. In conclusion,these SSR loci in the transcriptome of O. sinensis are high in frequency,rich in primitive types,high in polymorphism,and highly available,which will provides abundant candidate molecular markers for its genetic diversity analysis,resource identification protection,and gene function research.