Research On The Breeding Of Cyclosporin A High Yield Fusarium Strain And Its Genetic Characteristics

The research aims to improve the economic benefit of the important industrialstrain, Fusarium, which produces Cyclosporin A, through breeding high-yieldingstrain, understand the biosynthesis mechanism of Fusarium, and the hereditarycharacteristics difference between the high yielding strain and the low yieldingstrain as well.The paper first identified a cyclosporin A producing strain 421502 as Fusariumgenus by 18S rDNA molecular marker, which is concord with traditionaltaxonomy.High concentration protoplast with 7×10~5/ml was acquired by enzymolying the cellwall with snail enzyme and optimizing enzymatic hydrolysis conditions.Protoplasts regenerate on hypertonic PDA medium. Protoplast preparation andregeneration rate was 62.8% and 29.6 % respectively. Protoplast was used tomutation by laser to acquire high-yielding strain.Alanine racemase gene fragment of Fusarium 421502 of was cloned by two roundPCR using nested primers and confirmed that the gene is highly homologous withthat of Tolypocladium inflatum.