The Application Of Protoplast Mutation In Breeding Excellent Cordyceps Kyushuensis Strains

Cordyceps fungus is a kind of entomopathogenic fungi, its life cycle including asexual type and sexual type two stages. The stage of sexual type is know as caterpillar fungus. Cordyceps sinensis is one of the most famous and precious of all the types. It has many pharmaceutic effects. The growth of Cordyceps sinensis require a very demanding living environment, so its quantity is limited and can not satisfy the people's need. Cordyceps kyushuensis was collected from Mount Meng of Shandong province in 1996. Its teleomorph is a parasite on the larvae of Clanis bilineata Walker, and its anamorph was identified as Verficillium kyushuensis. There are many bioactive substances, such as nucleosides, polysaccharide, and so on, contained in Cordyceps kyushuensis.In this dissertation, the factors that affected the formation and regeneration of Cordyceps kyushuensis protoplasts were studied. In order to improve the production of nucleosides, protoplast mutagenesis was performed with UV and UV-HN02. High performance capillary electrophoresis was used to determine the concentration of cordycepin, adenine, uracil, adenosine, hypoxanthine, guanosine and uridine in the mutant strains and parent strains. Eight positive mutants with genetic stability were obtained. The results indicated that codycepin contained in U13, H6, H9, H26 and H31 was 2.12,1.69,1.76,1.73 and 1.41 times respectively that of their parents.The esterase isozyme and ISSR molecular marker were used in this research to detect the genetic variation of mutants. Both analyzed results showed that the entire genome sequences of eight mutants were different from parent strains, and the acquired characters of the mutants was caused by gene mutation. The high yield strains could be preserved and used in the next study.