| This paper describes the overview of research on taxonomic status of Ophicordyceps sinensis, morphology, life cycle, host Hepialidae larvae and other aspects. Ophicordyceps sinensis has not yet been realized by Koch’s postulate and had many theories, it was proposed the necessity of studing on strains related to Ophicordyceps. In addition, this article also describes the research of Ophicordyceps sinensis anamorph, strains related to Ophicordyceps and microbial interaction in details. On this basis, it was cleared the purpose and significance of this study by general biology studies on the physiological characteristics of related strains and understand the impact of strains related to Ophicordyceps. It would provide a theoretical basis for the development and usage of related strains and host Hepialidae larvae infestation.Using the existed Ophicordyceps sinensis, Hepialidae larvae, other resources and Ophicordyceps sinensis culture techniques in laboratory, 13 strains were isolated from Cordyceps collected in Gannan of Gansu province, and purified by the streak plate method and picked a single mycelium under the microscope. 7 strains were screened for significant inhibition on Ophicordyceps sinensis by flat confrontation experiment. Total DNA was extracted as a template for amplifying ITS sequence, sequencing and building phylogenetic trees. At the same time, the tests of biological characteristics of the optimum temperature, pH,optimal carbon and nitrogen sources on the screened strains were studied. Additionally, three times confrontion culture between the strains and Ophicordyceps sinensis with different inoculation time by flat confrontation experiment was studied separately, to observe the produced effect on Ophicordyceps sinensis in common growth. Observe the infection of related strains on Hepialidae larvae, morphological characteristics of Hepialidae larvae after infected. Finally, based on the above results, analyze the biological characteristics of the strains, the impact on the Ophicordyceps sinensis, and infection of Hepialidae larvae.There were 7 related strains being screened by experiment. In this study, the strains related to Ophicordyceps were definited those strains isolated from Ophicordyceps, impacted on Ophicordyceps sinensis and could infected Hepialidae larvae. The results of morphological and molecular biological identification declared that, 3-2-1,3-4-2 and 3-5-2 are Aspergillus versicolor, Aspergillus carneus and Aspergillus tennesseensis, 2F-2 is Isaria farinose, JC-1 is Paecilomyces hepiali, Beauveria bassiana is 1-1, all of which the identities are more than99%.The biological characteristics studies showed that, the optimum temperature and pH of3-2-1, 3-4-2 and 3-5-2 for culture was 23 ℃ and 6.5, the optimum carbon sources and nitrogen sources of 3-2-1 was maltose and bran. The optimum carbon sources and nitrogen sources of 3-4-2 and 3-5-2 was sucrose and bran. The optimum temperature and pH of 2G-3-2for culture was 23℃ and 6.5, the optimum carbon sources and nitrogen sources of 2G-3-2was maltose and milk. The optimum temperature and pH of 2F-2 for culture was 20-23℃ and7.5, the optimum carbon sources and nitrogen sources of 2F-2 was starch and soybean meal.The optimum temperature and pH of JC-1 for culture was 20-23℃ and 7.5, the optimum nitrogen sources and carbon sources of JC-1 was soybean meal, milk and maltose. The optimum temperature and pH of 1-1 for culture was 20-23℃ and 7.5, the optimum carbon sources and nitrogen sources of 1-1 was sucrose and bran.Confrontation experiments showed that, related strains of Ophicordyceps sinensis were produced inhibition when inoculated simultaneously. The inhibition of related strains to Ophicordyceps sinensis had changed when the Ophicordyceps sinensis inoculated 30 days in advance. The inhibition effects of the strains related to Ophicordyceps sinensis showed that,impact of 3-2-1 and 3-4-2 on Ophicordyceps sinensis were decreased with the size of the diameter of the Ophicordyceps sinensis colony, even changed into promotion by the later in three tests. Inhibition of 3-5-2 on the Ophicordyceps sinensis were weak, it would not be changed with the diameter of Ophicordyceps sinensis colony. 2G-3-2 and 2F-2 on Ophicordyceps sinensis had a strong inhibitory effect, and did not changed with the diameter of Ophicordyceps sinensis colony. JC-1 and 1-1 on the Ophicordyceps sinensis had strong inhibition, the inhibitory effect would weaken as the increase of diameter of Cordyceps fungus colony. All of the strains related to Ophicordyceps could produce an inhibitory effect on Ophicordyceps sinensis.Results of the strains infecting Hepialidae larvae proved that related strains and Ophicordyceps sinensis were able to infect Hepialidae larvae. The was demonstrated there were nutritional competition between the related strains and Ophicordyceps sinensis in Hepialidae larvae. All of the related strains were able to infect Hepialidae larvae although the abilities of infection were deferent for each strains, with descending JC-1, 1-1>2F-2> 3-4-2> 3-5-2> 3-2-1. It suggests there are same other relationship between these related strains and Ophicordyceps sinensis. needed to be researched further. |
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