Analysis Of Genetic Diversity Of Saccharomyces Cerevisiae

Saccharomyces cerevisiae is the most important microorganisms during wine-making.Studying the diversity of S.cerevisiae contributes to the development and utilization of yeast resources,also benefits the selection and breeding of excellent yeast.Comprehension of polymorphisms among S.cerevisiae is essential for studying the genetic basis of the phenotypic differences and for elucidating the evolutionary history of the species.Genetic variability of 176 strains,including yeast from Culture Collection of UCDavis,commercial strains and isolates from Shaanxi,was analyzed using four microsatellite markers(ScAAT1,YOR267c,C11,YPL009c).The PCR amplicon sizes were measured by capillary electrophoresis.Genetic parameters were analyzed by PopGen32.Distances between strains were calculated according to Jaccard Coefficient and the tree is built with UPGMA method by Ntsys,The genetic variability within populations and genetic relationships among them were discussed.The results were as folows:1.Fifty-one genotypes were generated among 53 strains from Culture Collection of UCDavis,17-23 alleles were found at per locus;43 genotypes were generated among 46 commercial wine strains,20-24 alleles were found at per locus;38 genotypes were generated among 77 S.cerevisiae from Shaanxi region,8-13 alleles were found at per locus.2.One hundred and seventy-six strains were amplified by four microsatellite prime pairs,which generated a total of 145 polymorphic bands,36.25 alleles for per locus.The heterozygosity observed was 0.4375-0.6743.The polymorphism information contents(PIC)of all strains at four loci were 0.8690-0.9227,suggesting that the four SSR loci were hypervariable.The results showed that extensive genetic polymorphism existed in the yeast populations.3.The four loci showed the similar allellic diversity in the three populations.For all three populations,ScAAT1 displayed the highest allellic diversity,and YPL009c displayed the lowest allellic diversity,and YOR267c showed the most remarkable differences in size between the smaller and the larger alleles.For each locus,unique alleles were found in each of the three population;many of their frequencies were very low.4.For ScAAT1 and YOR267c,alleles distributed evenly,did not concentrated in some areas,and had no significant difference between the three populations.For C11,alleles of yeast from UCDavis and Shaanxi region were distributed in the smaller part,while the alleles of commercial strains appeared in the larger part.It was opposite for YPL009c,alleles of yeast from UCDavis and Shaanxi region distributed in the larger part,while the alleles of commercial strains appeared in the smaller part.Genetic distance was calculated,it was nearer between commercial yeasts and Shaanxi yeasts,and it was farther between UCD yeasts and Shaanxi strains.5.The study discussed the data about Saccharomyces cerevisiae of northwest part of China,including Xinjiang,Ningxia,Shaanxi provinces,genetic analysis showed that genetic distance of S.cerevisiae between Xinjiang and Ningxia was nearer,and that between Xinjiang and Shaanxi was farther.For C11,allele’s distribution showed significant difference in three populations.Our yeast strains exhibited differences with foreign strains.