Brewer's Yeast Rapd Molecular Typing Markers

In this paper the RAPD reaction conditions of Saccharomyces cerivisiae was established. The genetic polymorphism and genetic similiarity of S.cerivisiae strains was also studied. And two strains of good fermentation properties were been marked.The DNA of 22 yeast strains was amplified with species-specific primers SC-1 and SC-2. There were 7 out of 14 unknown-specie strains with the 1170bp target DNA fragment appearing in the experiment .Tt indicates that they belong to S.cerivisiae.The reaction conditions of RAPD was improved and the results of RAPD DNA fingerprints showed an optimal reproducibility under this conditions: 50ng of DNA, 2.5mM Mg²⁺, 1.5U of Taq, 200μM dNTPs, 25pmol of primer and in total volume of 25μL; initial denaturation at 93℃for 2 min and 1 min for subsequent cycles, primer annealing at 36℃for 1 min and primer extension at 72℃for 2 min 40 cycles, final extension at 72℃for 10 min.The RAPD molecular markers were used to study the taxonomy of 15 S.cerivisiae strains. And 5 primers P07, P09, P11, P21 and P42 were selected in 50 oligonucleotide primers. They produced clear and stable DNA fingerprints and the DNA fingerprints showed a great polymorphism within these strains. Forty nine DNA fragments had been detected in this research and forty six of them were polymorphic markers. These results showed a great genetic polymorphism between the 15 strains. These strains can be divided into different groups according to the different genetic similarity and heredity distances.The fermentation research showed that these strains had different reducing speed of diacetyl and the contents of diacetyl and higher alcohols. It also indicated that strain YZU-APK and TZ-02 had a quick reducing speed of diacetyl with the peak value of diacetyl on the 4th day of fermentation. And the content of diacetyl was under 0.1 mg.L^-1 on the 14th day. The higher alcohols content of YZU-APK and TZ-02 were 66 mg.L^-1 and 78 mg.L^-1 at the end of fermentation. All these results indicated YZU-APK and TZ-02 were two strains of good fermentation performance.The DNA markers MP42-380,MP21-440,MP21^-1330 and MP21^-1900 that can...