SSR Analysis Of Saccharomyces Cerevisiae Population In Sourdough Starters Collected From The Old Silk Road(in China)

The unique geographical location,climate environment and high frequent human activities along the Old Silk Road(within China)(OSRC)results in unique fermented food by the indigenous diverse microbes.Mantou and nang from OSRC has a long history,they are dominant foods in the local people's daily meals.However,industrial strains are widely used in the food industry with the development of social economy and scientific technology.The consumption of mantou and nang fermented by traditional sourdough starter has decreased sharply in people's daily life,resulting in the substantial disappearance of indigenous S.cerevisiae resources and their diversity in these na?ve environments.Therefore,this paper used SSR(Simple Sequence Repeat)molecular marker to study the S.cerevisiae genetic diversity,population structure and genetic differences between geographic origins along OSRC.The results would lay the foundation for the further research of the evolution of the local S.cerevisie and the utilization of their unique phenotype characteristics.In this study,107 sourdough starters were collected from 44 counties in 5 provinces(Xinjiang,Gansu,Shanxi,Shaanxi,Henan)along the OSRC,and 996 yeast isolates were obtained,and 816 strains of them were identified as S.cerevisiae by the morphological characteristics on the WL nutrient agar medium and the lysine agar medium,the microscopic observation and 26 S r RNA D1/D2 PCR and sequences analysis.Among them,679 S.cerevisiae strains were used to analyze the genetic diversity via SSR-PCR with 12 primer pairs.The results are as follows:In Xinjiang,four hundred and thirty three strains of S.cerevisiae had great genetic diversity in various cities by SSR-PCR analysis.Total 455 polymorphic sites was obtained,among them,427 polymorphic sites were from190 yeast strains in Southern Xinjiang,417 polymorphic sites were from 243 strains in Northern Xinjiang.Na,Ne,He and I were all higher in the population from southern Xinjiang than that from northern Xinjiang.This indicated that the S.cerevisiae population in southern Xinjiang was more genetic diverse than that in the northern Xinjiang.The 433 S.cerevisiae strains were clustered into 7 populations,XJ? population was mainly from Shihezi,XJ?mainly from Yili,XJ? mainly from Tacheng and Turpan.XJ? mainly from Gongliu,XJ? mainly from Aksu,XJ? mainly from Kashgar,while the strains of XJ? populations was a mixture from various cities of Xinjiang.Through genetic site analysis,it was found that the genes of C5,C3,YKL172w3,YPL009 c,C4 and YOR267 c in the Xinjiang population were relatively stable.Compared with EC1118,each Xinjiang population had differentdegrees of variation,which may be related to the local geographical and climatic conditions.One hundred and twenty S.cerevisiae strains in Gansu province had 414 polymorphic sites.The S.cerevisaie population of Minqin and Gangu had had high genetic diversity indexes including Na,Ne,He and I,while the populations from Lintao and Huining,these genetic indexes shown low.The 120 S.cerevisiae strains were clustered into 6 populations,it was obviously related to the geographic location of the sourdough starter: GS? population was mainly from Minle,GS? population was mainly from Gulang and Gangu,GSIV population was mainly from Gangu,GS? population was mainly from Minqin,GS? population was mainly from Wuwei,while GS?population was mainly from various cites of Gansu.Based on the SSR genes sites,the S.cerevisiae in Gansu Province were found to be conserved at XV-110701/110935 and YOR267 c,YGL014c,VI-210250/210414.Six hundred and seventy-nine strains of S.cerevisiae from OSRC had 459 different polymorphic sites,Xinjiang and Gansu provinces shown high genetic diversity index such as Na,Ne,He and I,while the genetic diversity of S.cerevisaie populations from Shanxi and Henan were comparing low.OSRC 679 strains of S.cerevisiae were clustered into 5 populations,OSRCI population was mainly from northern Xinjiang,OSRC II population was mainly from southern Xinjiang,OSRC III population was mainly from Gansu,OSRC ? population was mainly from Henan,OSRC? population was mainly from Shaanxi.OSRC S.cerevisiae was relatively stable at chromosome XIII-86902/7140,YGL139 w,KL172w.S.cerevisiae populations in Gansu had a small variation on chromosome VI-897051/8970210;S.cerevisiae populations in Henan don't amplification site.on chromosome VI-210250/210414,S.cerevisiae populations from Shanxi Province don't amplification site in chromosomes VI-210250/210414 and YOR156 c,The S.cerevisiae in Xinjiang don ' t amplification site in the YPL009 c and YOR267 c genes.These variations may be related to local geographic and climatic conditions and the different local fermented foods.