2.4. Genome sequencing
For single nucleotide polymorphism (SNP) discovery in thepho13 -negative strain (YSX3), the genome of the YSX3 strain and its parental strain (L2612) were re-sequenced as described previously (Kim et al., 2013d). Briefly, genomic DNA was prepared by YeaStar Genomic DNA Kit (Zymo Research), and the DNA quality was evaluated on a 1% agarose gel. The genomic DNA samples were then sequenced using an Illumina HiSeq 2000 system, and the sequencing results were analyzed using the CLC Genomic Workbench (version 6.5) program. Among the 46 SNPs identified, 44 SNPs were found to be non-synonymous, and only 2 SNPs in YEN1 and GCR2 genes were confirmed in the YSX3 strain by Sanger sequencing. The two SNPs were also confirmed.