Changes in gene copy number shared by the fuel ethanol yeast strains. (A) A consensus karyoscope plot pooling the results of all the fuel ethanol strains relative to the lab strain S288C was generated by the program CGH-Miner (Wang et al. 2005). The plot displays statistically significantly altered copy number variations along each chromosome, and the chromosomes are shown in numerical order from top to bottom. (Red bars above the chromosome) significantly amplified regions, (green bars below the chromosome) significantly depleted regions; the height of the bars indicates in how many of the strains the significant observation was made (see reference scale within the figure). (B) Clustering dendogram of the entire genome microarray CGH data for the selected fuel yeast strains, together with the same data obtained with a baker's, brewer's, wine, and the lab strain S288C (self–self hybridization) (top), and relative gene copy number of selected yeast genes among the different strains (bottom). A scale of relative gene copy number is shown at the bottom. (C) Venn diagram of number of altered gene copy number variations of the selected fuel-ethanol yeast strains that were shared (or not) with a group of nine other industrial yeast strains (four wine, four baker's, and one ale brewing strain). (Red) Amplified genes, (black) polymorphic loci, (green) depleted genes (see Methods).

Detection of SNO2/3 genes in the industrial fuel ethanol yeasts. (A) Separation of chromosomes of yeast strains by PFGE; gel stained with ethidium bromide. (B) Southern blot of gel shown in panel A, hybridized with a probe for SNO2/3 to detect which chromosomes carry SNO2 or SNO3 genes. (Lane 1) Reference strain S288C, which contains SNO2 on chromosome XIV and SNO3 on chromosome VI (also indicated to the right of panel B); (lanes 2–6) strains CAT-1, PE-2, VR-1, BG-1, and SA-1, respectively. Roman numerals to the left of panel A are the chromosome numbers corresponding to the S288C chromosome bands (note that many are seen as doublets).

Typical growth curves of the diploid S288C-derived laboratory yeast strain GSY157 (A), the industrial fuel ethanol CAT-1 strain (B), as well as the diploid laboratory ura3/ura3 yeast strain FY1679 transformed with a multi-copy 2μ URA3⁺ control (no-insert) plasmid (C), or with the same plasmid containing a cloned SNO/SNZ gene pair from strain S288C (pBD1001) (D), in synthetic defined media (see Methods) containing 200 g/L glucose and lacking both pyridoxine and thiamin (green), or the same media supplemented with 1 mg/L of thiamin (blue).

Influence of thiamin (A) and sugar concentration (B,C) on the specific growth rate (see Methods) of the diploid S288C strain GSY157 (black circles) or the industrial strain CAT-1 (red triangles) in synthetic defined media lacking pyridoxine and thiamin (B), or the same media supplemented with thiamin (A,C). (D) Competition between the diploid S288C strain GSY157 (black circles) and the CAT-1-derived industrial strain EHD04 (red triangles) during sequential growth (see Methods) in synthetic defined media lacking pyridoxine and supplemented with thiamin. Unless otherwise indicated, the concentrations of glucose and thiamin in the medium were 200 g/L and 3 μM (1 mg/L), respectively.