title: The diverse role of Pdr12 in resistance to weak organic acids.
abstract: Resistance to weak organic acids is important relative to both weak organic acid preservatives and the development of inhibitor tolerant yeast as industrial production organisms. The ABC transporter Pdr12 is important for resistance to sorbic and propionic acid, but its role in tolerance to other weak organic acids with industrial relevance is not well established. In this study, yeast strains with altered expression of PDR12 and/or CMK1, a protein kinase associated with post-transcriptional negative regulation of Pdr12, were exposed to seven weak organic acids: acetic, formic, glycolic, lactic, propionic, sorbic and levulinic acid. These are widely used as preservatives, present in lignocellulosic hydrolysates or attractive as chemical precursors. Overexpression of PDR12 increased tolerance to acids with longer chain length, such as sorbic, propionic and levulinic acid, whereas deletion of PDR12 increased tolerance to the shorter acetic and formic acid. The viability of all strains decreased dramatically in acetic or propionic acid, but the Δpdr12 strains recovered more rapidly than other strains in acetic acid. Furthermore, our results indicated that Cmk1 plays a role in weak organic acid tolerance, beyond its role in regulation of Pdr12, since deletion of both Cmk1 and Pdr12 resulted in different responses to exposure to acids than were explained by deletion of Pdr12 alone.
authors.affiliation: VTT Technical Research Centre of Finland, Espoo, Finland.
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Nygård
authors.forename: Dominik
authors.initials: D
authors.lastname: Mojzita
authors.forename: Mervi
authors.initials: M
authors.lastname: Toivari
authors.forename: Merja
authors.initials: M
authors.lastname: Penttilä
authors.forename: Marilyn G
authors.initials: MG
authors.lastname: Wiebe
authors.forename: Laura
authors.initials: L
authors.lastname: Ruohonen
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism*; D002264:Carboxylic Acids / Q000633:toxicity*; D004361:Drug Tolerance; D017353:Gene Deletion; D015870:Gene Expression; D050296:Microbial Viability / Q000187:drug effects; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D018528:ATP-Binding Cassette Transporters; D002264:Carboxylic Acids; C472673:Pdr12 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins
keywords: Cmk1; Pdr12; Saccharomyces cerevisiae; plasma membrane transporters; weak organic acid tolerance