| Cordyceps sensu lato is a class of fungi that parasitize insects,spiders,nematodes,and certain macrocys spp.Elaphomyces,a general term for cordyceps sensu lato fungi.As a traditional and valuable Chinese medicinal material in China,Cordyceps s.l.fungi have a long history of use.The understanding of Cordyceps resources is rich,but the understanding of Cordyceps resources has only revealed the tip of the iceberg,and the investigation of Cordyceps resources has been strengthened,in order to provide scientific and technological support for the sustainable development and utilization of Cordyceps resources,and at the same time lay a solid foundation for the classification,system and evolution of Cordyceps taxonomy.Selenium(Se)is an important component of glutathione peroxidase(GSH-Px)in animals,and is an essential trace element for humans and animals in normal physiological activities.The traditional precious Chinese medicine “Cordyceps” and the miracle element “Selenium” are organically combined,giving play to the inherent and synergistic physiological effects of Cordyceps and Selenium,and the research on selenium enrichment of Cordyceps resources can expand the range of selenium-enriched species germplasm resources,and select carriers with better selenium enrichment ability.It is of great significance to study more kinds of selenium-enriched Cordyceps as medicines,health products and selenium supplemented functional foods.A total of 320 Cordyceps s.l.specimens were collected through field collection,and species identification of Cordyceps s.l.fungi was carried out according to morphological studies and 6 genes(ITS+SSU+LSU+TEF+RPB1+RPB2)combined with the study of maximum likelihood(ML)phylogenetic trees.At the same time,in this experiment,Cordyceps tenuipes,Isaria cicada and Cordyceps militaris were selected for selenium-rich experimental studies,and the results of the study were as follows:(1)In this study,64 specimens were selected for study,and the species were identified and classified according to morphological characteristics and multi-gene molecular phylogeny,,and 4 new species were proposed: Papiliomyces longiclavatum,Ophiocordyceps fenggangensis,Beauveria duyunensis,Ophiocordyceps carbro;2new record species: Cordyceps parvistroma,Blackwellomyces aurantiacus;25 known species were described.(2)In this study,99 ITS sequences,85 LSU sequences,44 RPB1 sequences,57RPB2 sequences,62 SSU sequences and 76 TEF sequences were obtained by extracting genes and sequencing them by PCR amplification.Added new sequences:the SSU sequence of Cordyceps parvistroma and the RPB2 sequence of Metacordyceps kusanagiensis.(3)In this study,Cordyceps tenuipes,Isaria cicada and Cordyceps militaris were selected for selenium-rich experimental research,and through liquid culture selenium enrichment experiments,the biomass of each cordyceps hyphal bulb cultured at different selenium concentrations was generally increased and then decreased,and the biomass of cordyceps cicada flowers increased most obviously,and the biomass changes of several cordyceps were: Cordyceps tenuipes < Cordyceps militaris <Cordyceps cicada.(4)Selenium content determination was performed by ICP-MS method for selenium-rich hyphal bulbs of Cordyceps militaris,Cordyceps chinensis and Cordyceps cicada flower,which had good accuracy and sensitivity.At the same time,the selenium-rich ability of three kinds of cordyceps is: Cordyceps tenuipes<Cordyceps militaris<Cordyceps cicada.(5)Selenium-rich culture of Cordyceps tenuipes,Isaria cicada and Cordyceps militaris were carried out by selecting the optimal selenium source concentration of30mg/L,and the activities of peroxidase(POD),Neutral Protease(NP)and amylase(AL)before and after selenium enrichment were determined.The results showed that there were significant differences between the selenium-rich group and the non-selenium-rich group,and after Cordyceps selenium-rich,the activity of POD and AL was reduced,and the activity of NP enzyme was increased. |
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