Whole Genome Resequencing Of A High-Yield Saccharomyces Cerevisiae For Alcohol Fermentation Of Sugarcane Molasses

Saccharomyces cerevisiae is a very important model strain in laboratory, as well as the most important strain of industries in fermaentation of fuel ethanol currently. It has a plenty of excellent characteristics, such as fermentation rapidly, mature technology, strong ability of ethanol production and so on in industrial applications. But what is the genomic features behind these excellent phenotype, and how to dig out those key genes to further enhance its industrial application performance are still the urgent problem to solve.In this study, a Saccharomyces cerevisiae strain named MF1002, which has excellent performance in molasses ethanol fermentation was genome sequencing using high-throughput next generation sequencing (NGS) technology. And then using the Bwa, Samtools, Blast and other bioinformatics analysis software for genome assembly, genome annotation, SNP analysis, genomic polymorphism analysis and key genes of the glycolytic pathway and cell cycle regulatory pathways analysis.By reason of the high heterozygosity characteric of industrial Saccharomyces cerevisiae genome, this study adopts the method of isolating haploid to sequencing. Firstiy, we have done the sporulation, haploid separation and verification test. The sporulation was utilizing McClary medium, and spore proportion can reach99%; then by cracking sporangium, inducing single spore germination to obtain haploid strains; At last, using PCR rapid verification method combined with flow cytometry analysis to identify the ploidy, successfully isolated yeast haploid strains.We use the whole genome shotgun strategy to sequencing. In the process of library construction, combined with concentration detection and agarose gel electrophoresis fragment size detection to assess library quality. Library of nucleotide chain fragment size within a range of250-850bp, with a center300-550bp, and the concentration is7-13ng/μl, above range is more reasonable.Data analysis is mainly based on Linux system platform, to assess the data quality, Triming, assembly, annotation, SNP analysis and structural polymorphism was using Fastqc, bwa, samtools and so on. The result of assemblying is16chromosomes, a total of11948100bp, depth49×, GC content38.3%. Then6306genes annotated and67898SNP compared with the model strain S288c; analysis of303deletion,327insertion, and a total of842positions of the structure variation of structural polymorphism.Combined with the full genome sequence information of S288c and industrial ethanol fermentation strains JAY-291, CAT-1, the glycolytic pathway and cell cycle pathway related genes with MF1002were compared in amino acid level, and the larger variation of gene were10, 38respectively. It suggests that its may be the key genes associated with MF1002fermentation ability and growth rate. And they can be used as the strain of genetically engineered sites.