Background: Significant genetic diversity exists across Saccharomyces strains. Natural isolates and domesticated brewery and industrial strains are typically more robust than laboratory strains when challenged with inhibitory lignocellulosic hydrolysates. These strains also contain genes that are not present in lab strains and likely contribute to their superior inhibitor tolerance. However, many of these strains have poor sporulation efficiencies and low spore viability making subsequent gene analysis, further metabolic engineering, and genomic analyses of the strains challenging. This work aimed to develop an inhibitor tolerant haploid with stable mating type from S. cerevisiae YB-2625, which was originally isolated from bagasse.
Results: Haploid spores isolated from four tetrads from strain YB-2625 were tested for tolerance to furfural and HMF. Due to natural mutations present in the HO-endonuclease, all haploid strains maintained a stable mating type. One of the haploids, YRH1946, did not flocculate and showed enhanced tolerance to furfural and HMF. The tolerant haploid strain was further engineered for xylose fermentation by integration of the genes for xylose metabolism at two separate genomic locations (ho∆ and pho13∆). In fermentations supplemented with inhibitors from acid hydrolyzed corn stover, the engineered haploid strain derived from YB-2625 was able to ferment all of the glucose and 19% of the xylose, whereas the engineered lab strains performed poorly in fermentations.
Conclusions: Understanding the molecular mechanisms of inhibitor tolerance will aid in developing strains with improved growth and fermentation performance using biomass-derived sugars. The inhibitor tolerant, xylose fermenting, haploid strain described in this work has potential to serve as a platform strain for identifying pathways required for inhibitor tolerance, and for metabolic engineering to produce fuels and chemicals from undiluted lignocellulosic hydrolysates.
Increase the total number of rows showing on this page using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table.
| Evidence ID | Analyze ID | Gene/Complex | Systematic Name/Complex Accession | Qualifier | Gene Ontology Term ID | Gene Ontology Term | Aspect | Annotation Extension | Evidence | Method | Source | Assigned On | Reference |
|---|
Increase the total number of rows showing on this page using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table; click on the small "i" buttons located within a cell for an annotation to view further details.
| Evidence ID | Analyze ID | Gene | Gene Systematic Name | Phenotype | Experiment Type | Experiment Type Category | Mutant Information | Strain Background | Chemical | Details | Reference |
|---|
Increase the total number of rows showing on this page using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table.
| Evidence ID | Analyze ID | Gene | Gene Systematic Name | Disease Ontology Term | Disease Ontology Term ID | Qualifier | Evidence | Method | Source | Assigned On | Reference |
|---|
Increase the total number of rows displayed on this page using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; to filter the table by a specific experiment type, type a keyword into the Filter box (for example, “microarray”); download this table as a .txt file using the Download button or click Analyze to further view and analyze the list of target genes using GO Term Finder, GO Slim Mapper, or SPELL.
| Evidence ID | Analyze ID | Regulator | Regulator Systematic Name | Target | Target Systematic Name | Direction | Regulation of | Happens During | Regulator Type | Direction | Regulation Of | Happens During | Method | Evidence | Strain Background | Reference |
|---|
Increase the total number of rows showing on this page by using the pull-down located below the table, or use the page scroll at the table's top right to browse through its pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table.
| Site | Modification | Modifier | Source | Reference |
|---|
Increase the total number of rows showing on this page by using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table; click on the small "i" buttons located within a cell for an annotation to view further details about experiment type and any other genes involved in the interaction.
| Evidence ID | Analyze ID | Interactor | Interactor Systematic Name | Interactor | Interactor Systematic Name | Allele | Assay | Annotation | Action | Phenotype | SGA score | P-value | Source | Reference | Note |
|---|
Increase the total number of rows showing on this page by using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table; click on the small "i" buttons located within a cell for an annotation to view further details about experiment type and any other genes involved in the interaction.
| Evidence ID | Analyze ID | Interactor | Interactor Systematic Name | Interactor | Interactor Systematic Name | Assay | Annotation | Action | Modification | Source | Reference | Note |
|---|
Increase the total number of rows showing on this page by using the pull-down located below the table, or use the page scroll at the table's top right to browse through its pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table.
| Complement ID | Locus ID | Gene | Species | Gene ID | Strain background | Direction | Details | Source | Reference |
|---|
Increase the total number of rows displayed on this page using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table; download this table as a .txt file using the Download button;
| Evidence ID | Analyze ID | Dataset | Description | Keywords | Number of Conditions | Reference |
|---|
Increase the total number of rows displayed on this page using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table; download this table as a .txt file using the Download button;
| Evidence ID | Analyze ID | File | Description |
|---|