Studies On Genetic Diversity And Biological Characteristics Of Paecilomyces Farinosus

The penicilliosis of Hepialus gonggaensis caused by Paecilomyces farinosus is one of the main diseases during artificial breeding of Hepialus gonggaensis. To make certain the source and transmission routes of the Paecilomyces farinosus and to provide the basis of prediction and prevention about the penicilliosis of Hepialus gonggaensis, the genetic diversity by ISSR molecular marker method and biological characteristics about 82 strains isolated from different insect state development period and the corresponding growth environment medium were studied. The results are as follows:1. Genetic diversity of Paecilomyces farinosusThe experiment established a Paecilomyces farinosus ISSR-PCR reaction system, and genetic diversity of Paecilomyces farinosus was studied. With Paecilomyces farinosus genomic DNA as a template, the 4 important parameters (primer, Taq enzyme, template, MIX mixture) of ISSR-PCR reaction system were optimized by orthogonal design method (L16(43)),25μL PCR reaction system including template DNA 70 ng, primer 0.5μmol/L, MIX mixture 8μL, Taq enzyme 1 U. Using the optimized system,10 primers with clear band, high polymorphism, and good stability from 20 ISSR primers released by Columbia University in Canada for PCR amplification were picked out, and extended out 72 amplified loci including 46 polymorphism loci, molecular weight in 150-2000bp, the percentage of polymorphism was 63.9%. Clustering analysis results showed that 82 strains have an abundant genetic polymorphism, the genetic distance between,0.561-0.912,82 strains could be divided into 5 groups in the similarity coefficient 0.606.The genetic diversity of 82 Paecilomyces farinosus strains, isolated from artificial breeding base of Hepialus gonggaensis, develop equipment, indoor air, the external environment, waste, and insect body, was analyzed by ISSR molecular markers method, the result showed that:the 82 strains have different clustering relations, artificial breeding of Hepialus gonggaensis for years, made the Paecilomyces farinosus have abundant genetic diversity and full communication with pathogenic bacteria from Linzhi in Tibet, Maqu in Gansu, Xiaojin in Sichuan, all environment and medium of training base could be the source of penicilliosis of Hepialus gonggaensis. Paecilomyces farinosus from the body of pests have the high homology with strains from the experiment room (No.8, No.9, No.10), part of the central hall, building the south wall, inferencing that there are many pathogenic causing penicilliosis of Hepialus gonggaensis. The experiment room (No.8, No.9, No.10) and the central hall are the main pathogenic, building the south wall is the second pathogenic, illustrated that strains cause disease of Hepialus gonggaensis are universal and diversity.2. The biological characteristics of Paecilomyces farinosusThe biological characteristics of strain 2-M3-1,2-J4-1,2-E2-2,1-C6-2,1-WQN-1, 1-E10-1,2-G5, L-8, sleeted depending on the degree of genetic differences (Numbered in the order:33,13,22,82,20,58,68,54) were studied by Duncan’s for data analysis and processing. The results are as follows:The wide range of temperature is adapted to Paecilomyces farinosus, the temperature range of growth is 5℃-30℃, and the optimum temperature is 20℃-25℃. For sporulation, the temperature range is 10℃-25℃, and the optimum temperature is 20℃. The pH value range for the strains growth is pH4-pH12, at pH7, the fastest speed of growth and the most amount of spore were achieved in the most of stains, which has a significant differences with other pH treatment. The strains grow the fastest under the condition of the dark, with the increase of light growth speed slows down. Carbon source is conducive to the growth of strains, Paecilomyces farinosus grow faster in the medium containing glucose, lactose and starch than in the contrast medium. The growth of hyphae is better in the medium containing glucose than in the medium containing of other carbon. The quantity and quality of hyphae are worst in the medium containing starch, but of spores are best. Nitrogen source is benefit to spore production, glycine, potassium nitrate and ammonium sulfate are maked good use by Paecilomyces farinosus, where colony is thicker and spore is more abundant than in the contrast medium. The most suitable nitrogen source is glycine for growth and sporulation, which has a significant difference with other treatment.There were difference in growth and sporulation of strains in optimum condition. There are differences between strain 2-G5 and others in terms of the optimal light conditions of growth and spore production, the optimum nitrogen source of growth and spore production, the optimum carbon source of growth. But the optimal growth conditions of strain 2-E2-2and L-8 are the same.