Unveiling genetic anchors in Saccharomyces cerevisiae: QTL mapping identifies IRA2 as a key player in ethanol tolerance and beyond

• Published in: Molecular genetics and genomics : MGG Vol. 299; no. 1; p. 103
• Main Authors: Tristão, Larissa Escalfi, de Sousa, Lara Isensee Saboya, de Oliveira Vargas, Beatriz, José, Juliana, Carazzolle, Marcelo Falsarella, Silva, Eduardo Menoti, Galhardo, Juliana Pimentel, Pereira, Gonçalo Amarante Guimarães, de Mello, Fellipe da Silveira Bezerra
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.12.2024; Springer Nature B.V
• Subjects: Acetic acid; acid tolerance; alleles; Animal Genetics and Genomics; Biochemistry; bioethanol; Biofuels; Biomedical and Life Sciences; Chromosome Mapping; Drug tolerance; economic sustainability; Ethanol; Ethanol - metabolism; Ethanol - pharmacology; Fermentation; Fermentation - genetics; Gene frequency; Gene mapping; Genetic markers; genomics; GTPase-Activating Proteins; heat tolerance; Human Genetics; Industrial applications; Life Sciences; Microbial Genetics and Genomics; Missense mutation; mutation rate; Mutation, Missense; Original Article; oxygen; Plant Genetics and Genomics; Population genetics; Population studies; Quantitative Trait Loci; Saccharomyces cerevisiae; Saccharomyces cerevisiae - drug effects; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae Proteins - genetics; Strains (organisms); stress tolerance; sugars; Temperature tolerance; Yeast; yeasts; IRA2; Ethanol tolerance; QTL mapping
• ISSN: 1617-4615; 1617-4623; 1617-4623
• DOI: 10.1007/s00438-024-02196-5

Ethanol stress in Saccharomyces cerevisiae is a well-studied phenomenon, but pinpointing specific genes or polymorphisms governing ethanol tolerance remains a subject of ongoing debate. Naturally found in sugar-rich environments, this yeast has evolved to withstand high ethanol concentrations, primarily produced during fermentation in the presence of suitable oxygen or sugar levels. Originally a defense mechanism against competing microorganisms, yeast-produced ethanol is now a cornerstone of brewing and bioethanol industries, where customized yeasts require high ethanol resistance for economic viability. However, yeast strains exhibit varying degrees of ethanol tolerance, ranging from 8 to 20%, making the genetic architecture of this trait complex and challenging to decipher. In this study, we introduce a novel QTL mapping pipeline to investigate the genetic markers underlying ethanol tolerance in an industrial bioethanol S. cerevisiae strain. By calculating missense mutation frequency in an allele located in a prominent QTL region within a population of 1011 S. cerevisiae strains, we uncovered rare occurrences in gene IRA2 . Following molecular validation, we confirmed the significant contribution of this gene to ethanol tolerance, particularly in concentrations exceeding 12% of ethanol. IRA2 pivotal role in stress tolerance due to its participation in the Ras-cAMP pathway was further supported by its involvement in other tolerance responses, including thermotolerance, low pH tolerance, and resistance to acetic acid. Understanding the genetic basis of ethanol stress in S. cerevisiae holds promise for developing robust yeast strains tailored for industrial applications.