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Screening the yeast deletant mutant collection for hypersensitivity and hyper‐resistance to sorbate, a weak organic acid food preservative
Author(s) -
Mollapour Mehdi,
Fong Dahna,
Balakrishnan Krishna,
Harris Nicholas,
Thompson Suzanne,
Schüller Christoph,
Kuchler Karl,
Piper Peter W.
Publication year - 2004
Publication title -
yeast
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.923
H-Index - 102
eISSN - 1097-0061
pISSN - 0749-503X
DOI - 10.1002/yea.1141
Subject(s) - sorbic acid , biology , mutant , biochemistry , potassium sorbate , yeast , saccharomyces cerevisiae , preservative , microbiology and biotechnology , food science , gene , sugar
Abstract Certain yeasts cause large‐scale spoilage of preserved food materials, partly as a result of their ability to grow in the presence of the preservatives allowed in food and beverage preservation. This study used robotic methods to screen the collection of Saccharomyces cerevisiae gene deletion mutants for both increased sensitivity and increased resistance to sorbic acid, one of the most widely‐used weak organic acid preservatives. In this way it sought to identify the non‐essential, non‐redundant activities that influence this resistance, activities that might be the potential targets of new preservation strategies. 237 mutants were identified as incapable of growth at pH 4.5 in presence of 2 m M sorbic acid, while 34 mutants exhibit even higher sorbate resistance than the wild‐type parental strain. A number of oxidative stress‐sensitive mutants, also mitochondrial mutants, are sorbate‐sensitive. This appears to reflect the importance of sustaining a reducing intracellular environment (high reduced glutathione levels and NADH/NAD and NADPH/NADP ratios). Sorbate resistance is also very severely compromised in mutants lacking an acidified vacuole, in vacuolar protein sorting ( vps ) mutants, in mutants defective in ergosterol biosynthesis ( erg mutants) and with several defects in actin and microtubule organization. Sorbate resistance is, however, elevated with the loss of the Yap5 transcription factor; with single losses of two B‐type cyclins (Clb3p, Clb5p); and with loss of a plasma membrane calcium channel activated by endoplasmic reticulum stress (Cch1p/Mid1p). Copyright © 2004 John Wiley & Sons, Ltd.