Evolutionary engineering and transcriptomic analysis of nickel-resistant Saccharomyces cerevisiae

Area of Science:

• Environmental Science
• Microbiology
• Genetics

Background:

• Industrial development increases nickel exposure, leading to pollution and human health issues.
• Limited understanding exists regarding nickel response, transport, and tolerance in eukaryotes.
• Saccharomyces cerevisiae serves as a model eukaryote for studying cellular responses to toxic metals.

Purpose of the Study:

• To investigate nickel resistance mechanisms in the model eukaryote Saccharomyces cerevisiae.
• To develop yeast strains with enhanced tolerance to nickel chloride (NiCl2).
• To identify genetic pathways involved in nickel resistance.

Main Methods:

• Evolutionary engineering using batch selection with gradually increasing nickel stress levels.
• Phenotypic characterization of nickel-resistant mutants, including cross-resistance assays.
• Global transcriptomic analysis to identify differentially expressed genes.

Main Results:

• Selected nickel hyper-resistant mutants capable of tolerating up to 5.3 mM NiCl2.
• Demonstrated cross-resistance to iron, cobalt, zinc, and manganese stresses in the selected mutants.
• Observed twofold higher nickel accumulation in mutants compared to the reference strain.
• Transcriptomic analysis revealed 640 upregulated genes associated with iron homeostasis, stress response, and oxidative damage.

Conclusions:

• Nickel resistance in Saccharomyces cerevisiae involves complex genetic pathways.
• Nickel resistance shares common mechanisms with iron and cobalt resistance, general stress response, and oxidative damage pathways.
• Engineered yeast strains provide a valuable model for studying nickel toxicity and developing bioremediation strategies.