Details

Autor(en) / Beteiligte

• Higgins, Douglas A
• Young, Megan K M
• Tremaine, Mary
• Sardi, Maria
• Fletcher, Jenna M
• Agnew, Margaret
• Liu, Lisa
• Dickinson, Quinn
• Peris, David
• Wrobel, Russell L
• Hittinger, Chris Todd
• Gasch, Audrey P
• Singer, Steven W
• Simmons, Blake A
• Landick, Robert
• Thelen, Michael P
• Sato, Trey K

Titel

Natural Variation in the Multidrug Efflux Pump SGE1 Underlies Ionic Liquid Tolerance in Yeast

Ist Teil von

• Genetics (Austin), 2018-09, Vol.210 (1), p.219-234

Ort / Verlag

United States: Genetics Society of America

Erscheinungsjahr

2018

Quelle

MEDLINE

Beschreibungen/Notizen

• Imidazolium ionic liquids (IILs) have a range of biotechnological applications, including as pretreatment solvents that extract cellulose from plant biomass for microbial fermentation into sustainable bioenergy. However, residual levels of IILs, such as 1-ethyl-3-methylimidazolium chloride ([C C im]Cl), are toxic to biofuel-producing microbes, including the yeast strains isolated from diverse ecological niches differ in genomic sequence and in phenotypes potentially beneficial for industrial applications, including tolerance to inhibitory compounds present in hydrolyzed plant feedstocks. We evaluated >100 genome-sequenced strains for tolerance to [C C im]Cl and identified one strain with exceptional tolerance. By screening a library of genomic DNA fragments from the [C C im]Cl-tolerant strain for improved IIL tolerance, we identified , which encodes a plasma membrane multidrug efflux pump, and a previously uncharacterized gene that we named ( ), which encodes a predicted membrane protein. Analyses of sequences from our panel of strains together with growth phenotypes implicated two single nucleotide polymorphisms (SNPs) that associated with IIL tolerance and sensitivity. We confirmed these phenotypic effects by transferring the SNPs into a [C C im]Cl-sensitive yeast strain using CRISPR/Cas9 genome editing. Further studies indicated that these SNPs affect Sge1 protein stability and cell surface localization, influencing the amount of toxic IILs that cells can pump out of the cytoplasm. Our results highlight the general potential for discovering useful biotechnological functions from untapped natural sequence variation and provide functional insight into emergent alleles with reduced capacities to protect against IIL toxicity.