| Shanxi’s unique geographical location may breed abundant Cordyceps resources,but only Cordyceps shanxiensis and Cordyceps barnesii are documented in Shanxi at present.In this study,Cordyceps samples collected from southern Shanxi Province were identified,and then the genetic diversity and floristic fungal diversity of dominant Ophiocordyceps nigrella were studied.By extracting DNA and amplifying typical nuclear gene fragments(ITS,rpb1,rpb2,SSU,LSU,TEF),we found that Cordyceps in southern Shanxi was mainly divided into three categories,including Ophiocordyceps nigrella,Cordyceps shanxiensisbarnesii and a putative new species.As a new record species in China,Ophiocordyceps nigrella is a Fungus-Insect complex formed by the host of Ophiocordyceps nigrella on beetle larvae(also known as grubs).According to the latest classification system of Cordyceps-related fungi,O.nigrella belongs to Ascomycota,Sordariomycetes,Hypocreales,Ophiocordycipitaceae.According to the results of molecular biology identification,we have done morphological studies of three kinds of cordyceps.The results showed that the host body of Ophiocordyceps nigrella was yellowish-brown,and its subunits were single;stalks were brown;pregnant parts were gray-black,columnar;ascospores were superficial,inverted pear-shaped.At maturity,the orifice leaked out,the ascospores were long columnar,and the ascospores were broken,and the length of single spore was 26.9-30 μm,width 2.93 μm.The host of suspected new species of Cordyceps is yellowish brown,and its subunits were single;stalks were brown,pregnant part is grayish-brown,columnar,.ascospores were buried,narrow oval.The Cordyceps shanxiensisbarnesii is was yellowish-brown,and its subunits were single;stalks were brown,pregnant parts were grayblack,columnar.The ascus shell is buried and oval.At maturity,the orifice leaked out.We preliminarily studied the genetic diversity of Ophiocordyceps nigrella from four collecting sites.The results showed that ITS(528 bp),rpb1(694 bp)and MAT121(1215 bp)gene fragments of Cordyceps had only one base difference,while the sequence of DNA lyase gene had great variation.Ten different sites were found.It may be that these four places are relatively close,so there is no genetic differentiation.In order to further study the microbial diversity of O.nigrella,we not only collected Ophiocordyceps nigrella,but also collected soil samples 0 cm and 20 cm away from Ophiocordyceps nigrella for microbial diversity analysis(T1-T3 was soil samples 0 cm away from Ophiocordyceps nigrella,T4-T5 was soil samples 20 cm away from Ophiocordyceps nigrella).The results showed that Ophiocordyceps nigrella was the dominant bacteria in the fruiting bodies and bodies of Cordyceps militaris.The dominant bacteria in soil samples were Ascomycota 、 Mortierella 、 Tetracladium 、Oidiodendron 、 Ganoderma 、 Ophiocordyceps nigrella,The richness of Nectriaceae in T1 soil samples was also higher,and that in T2 soil samples was higher than the other four.The difference of soil samples is that the richness of Ciboria-betulae is higher than that of Tetracladium and Mortierella.In the process of analysis,we found that there were many unclassified fungi in the soil samples,and they were dominant fungi.They might promote the growth of Ophiocordyceps nigrella.The study of these fungi might be helpful to the artificial cultivation of Ophiocordyceps nigrella.As a new record species in Shanxi and even the whole country,the biological and pharmacological studies of Ophiocordyceps nigrella are very few,which is very unfavorable to its development and utilization,and can not play its real value.This is a great waste of resources,so the follow-up analysis of Ophiocordyceps nigrella is very important. |
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