The Screening Of Sporogenous Medium And Haploid Separation Of Saccharomyces Cerevisiae 1450

The process of inducing yeast to produce spores and then obtaining its haploid is crucial in Yeast Genetics and Breeding. This is indispensable for analyzing the inheritance of acquired characters and preparing the parent strains for hybridization. The spores can be obtained only in fitting sporulation condition. On the barren condition of nutrition, the trophosome of S.Cerevisiae transits into haploid from the former diploid through the process of meiosis, forming sporangium. None of the present common yeast spores-breeding culture media was suitable for all the yeasts to produce their spores. Therefore, the spores-breeding experiment of S.Cerevisiae 1450 was undertaken under different spores-breeding conditions in this essay. Then, the optimum culture medium was selected for the separation of the haploid of S.Cerevisiae 1450. Next, a haploid strain with good biological function was screened out through zymotechnics method so as to be applied in the next breeding experiment.The main research results are as follows.1. After the selective preference of four common yeast spores-breeding culture media, Mcclary culture medium was confirmed as the optimum one for S.Cerevisiae 1450.2. The optimum temperature and time for S.Cerevisiae 1450 in the Mcclary culture medium were 25℃-28℃and 5-7d, separately. The influence of temperature over the spores-breeding capability of S.Cerevisiae 1450 was connected with the activity of concerning enzymes.3. In the experiment of identifying the ferment capability of strains, the ferment capability varies largely among different haploid strains. The supposed reason was speculated that the ferment capability of S.Cerevisiae was controlled by multiple genes. And through the comprehensive analysis of the fermentation capability and performance, a haploid strain S-3 with good biological function was obtained and could be used as the parent strains in the future hybridization experiment. 4. The growth curve of the haploid S-3 was determined, and the results showed that it's better to choose the strains around 9h in the breeding job.