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Updated: Jul 13, 2026
Rapid Identification of Chemical Genetic Interactions in Saccharomyces cerevisiae
Published on: April 5, 2015
Genome-wide screen for oxalate-sensitive mutants of Saccharomyces cerevisiae
V Cheng1, H U Stotz, K Hippchen
1Department of Food Science and Technology, Wiegand Hall, Oregon State University, Corvallis, OR 97331-6602, USA.
Abstract:
Oxalic acid is an important virulence factor produced by phytopathogenic filamentous fungi. In order to discover yeast genes whose orthologs in the pathogen may confer self-tolerance and whose plant orthologs may protect the host, a Saccharomyces cerevisiae deletion library consisting of 4,827 haploid mutants harboring deletions in nonessential genes was screened for growth inhibition and survival in a rich medium containing 30 mM oxalic acid at pH 3. A total of 31 mutants were identified that had significantly lower cell yields in oxalate medium than in an oxalate-free medium. About 35% of these mutants had not previously been detected in published screens for sensitivity to sorbic or citric acid. Mutants impaired in endosomal transport, the rgp1Delta, ric1Delta, snf7Delta, vps16Delta, vps20Delta, and vps51Delta mutants, were significantly overrepresented relative to their frequency among all verified yeast open reading frames. Oxalate exposure to a subset of five mutants, the drs2Delta, vps16Delta, vps51Delta, ric1Delta, and rib4Delta mutants, was lethal. With the exception of the rib4Delta mutant, all of these mutants are impaired in vesicle-mediated transport. Indirect evidence is provided suggesting that the sensitivity of the rib4Delta mutant, a riboflavin auxotroph, is due to oxalate-mediated interference with riboflavin uptake by the putative monocarboxylate transporter Mch5.
Insights
This study screened yeast mutants for oxalic acid tolerance, identifying 31 sensitive strains. Many mutants involved in vesicle-mediated transport showed sensitivity, suggesting its role in fungal virulence and host protection.
Area of Science:
- Mycology
- Molecular Biology
- Genetics
Background:
- Oxalic acid is a key virulence factor in phytopathogenic fungi.
- Understanding fungal self-tolerance mechanisms is crucial for developing plant disease control strategies.
- Investigating yeast orthologs can reveal conserved pathways involved in pathogen virulence and host defense.
Purpose of the Study:
- To identify Saccharomyces cerevisiae genes conferring tolerance to oxalic acid.
- To discover yeast genes whose orthologs in pathogens may enable self-tolerance.
- To find yeast genes whose plant orthologs might protect hosts from fungal pathogens.
Main Methods:
- Screened a library of 4,827 haploid Saccharomyces cerevisiae deletion mutants.
- Assessed growth inhibition and survival in rich medium with 30 mM oxalic acid at pH 3.
- Identified mutants with significantly reduced cell yields in the presence of oxalic acid.
Main Results:
- Identified 31 yeast mutants sensitive to oxalic acid.
- Found significant overrepresentation of mutants impaired in endosomal transport (e.g., rgp1Δ, ric1Δ, snf7Δ, vps16Δ, vps20Δ, vps51Δ).
- Five mutants (drs2Δ, vps16Δ, vps51Δ, ric1Δ, rib4Δ) exhibited lethal sensitivity to oxalate; most are involved in vesicle-mediated transport.
Conclusions:
- Vesicle-mediated transport is critical for yeast tolerance to oxalic acid.
- This pathway is a potential target for understanding fungal virulence and developing host-protective strategies.
- Oxalic acid may interfere with riboflavin uptake via the Mch5 transporter in sensitive mutants like rib4Δ.
