The Mutagenesis And Breeding Of Efficient Insecticidal Strains By Physicochemical Mutagenesis And Genome Shuffling

Spinosad is a new biological pesticides, which can control most variety of pests,including lepidopterans,Lepidoptera,Orthopter, Diptera and coleopterans. Spinosyns are secondary metabolites of soilactinomycete, Saccharopolyspora spinosa. Spinosyns has great prospects with a broad spectrum insecticide, insecticidal activity, and safty to non-target organisms.However, the capability of wide type of Saccharopolyspora spinosa is very limited, and it is hoped to improve the synthetic ability further up. In this study I select Saccharopolyspora spinosa by mutation so as to improve the synthetic ability of spinosad. At first, aiming at the two mutagens,I conduct lethal experiments to spores of Saccharopolyspora spinosa, and design mutagens in different concentration and different processing time to discuss their lethal effect:0.5mg/mL、0.7mg/mL、1.0mg/mL、1.2mg/mL、1.5mg/mL, time gradient is30min、60min;the concentration of LiCl is0.05%、0.1%、0.15%、0.2%、0.25%respectively。 Through the curve of lethality rate, I confirm the process condition of mutation with compound NTG-LiCl. The results indicate that using0.15%LiCl medium to let go the mutagenesis after disposing with lmg/mL NTG for1h at30℃make the yield of spinosad supremely increased. After two circles of mutation, I pick4primitive strains to conduct protolast fusion. Finally, single out one mutagenesis strain from a more primitive strain with one time higher production, detect its genetic stability at the same time, and find this character can be inherited stablely, so we achieve the aim of the improving the compound of spinosad.In addition, on the basis of this high output strain, I compare it with primitive strain in several aspects such as colonial morphology and speed of growth. It may have some directive function for latter research of strains. Besides, this study ascertain the best condition between process of spore cultivating through comparing these two strains’ ability of generating spores on flat.