Study On Isolation,Identification And Metabolic Activity Of Isaria Cicadae

Isaria cicadae,the original name was Paecilomyces cicadae,which is belong to Clavicipitaceae,is the anamorph of Cordyceps cicadae shing.As a biocontrol agent,spores and metabolic liquid of Isaria cicadae have high insecticidal activity.For the metabolic Isaria cicadae liquid has also played a role in the prevention of plant pathogen,which has played multiple roles besides insecticide.In this paper,Strain 12,separation and purification of Cordyceps cicadae from Guiyang forest park was characterized by morphological observation,Biolog automatic micro-analysis system and PCR primers developed for analysis of the ITS region of rDNA.We test the bioactivity of Strain 12 spores liquid against Brevicoryne brassicae.The modes of action of metabolic liquid on the aphids were studied on stomach toxicity,contact toxicity,feeding deterrent and new-born aphids.AChE,GST,CarE,Na-K ATPase,PPO and AMS were determined in order to explore the mechanism of metabolic liquid on aphids.The inhibitory effects of metabolic liquid on Pilidiella guizhouensis were investigated by using drug-containing culture medium method and coating method,respectively.The main results were as follows:1.Strain 12,separation and purification of Cordyceps cicadae from Guiyang forest park was characterized by morphological observation,Biolog automatic microanalysis system and PCR primers developed for analysis of the ITS region of rDNA.The identification results showed Strain 12 was Isaria cicadae.2.At room temperature,the spore suspension of Strain12 with different concentration had a strong pathogenicity against aphids,and the mortality of aphids increased with the increase of spore suspension concentration and the prolongation of treatment time.When the spores concentration was 2.5 × 105 spores / mL,the death began to occur on the 3rd day,and then the cumulative mortality rate increased gradually.After 7 days,the corrected mortality was 82.08%.Aphids began to die at the first two at a concentration of 2.5 × 107 spores / mL,after that the mortality increased,and the corrected mortalityreached 92.0% after 7 days.3.The results indicated that Strain12 had a significant inhibitory effect on the growth of aphids,and the aphids were mainly influenced by feeding deterrent and refuse to produce.The m deterrent rate was 88.89% on the second day.In addition,the metabolic liquid had a significant effect on the production of aphids,and the rate of new-born aphids on the side of the water was 98.63%.It can be seen that the secondary metabolites of Isaria cicadae had a tendency of feeding deterrent and refuse to produce against aphids.4.Compared with the control group,there was no significant change in the six enzymes on the first day of the metabolic liquid treatment.But from the 2nd day,the activities of acetylcholinesterase(AChE)and Na-K ATPase decreased and glutathione S-transferase(GST)increased in the treatment group.While the activities of carboxyesterase(CarE)and polyphenol oxidase(PPO)did not change significantly.5.The results showed that the metabolic liquid of Strain 12 had a significant inhibitory effect on the colony growth of Isaria cicadae,and the inhibition rate was 46.27% at 7 days.Besides,the inhibitory effect can be extended to the significantly inhibited of sclerotia growth.The results showed that the concentration of metabolic solution of Strain 12 affected the inhibitory effect of Pilidiella guizhouensis,and the inhibitory effect was 32.14% when the concentration of metabolic liquid was 20%.