Mitochondrial DNA and temperature tolerance in lager yeasts

Area of Science:

• Microbiology
• Genetics
• Biotechnology

Background:

• Mitochondrial genome (mtDNA) plays a crucial role in organismal temperature adaptation.
• Different species within the yeast genus Saccharomyces exhibit varying temperature tolerances, influencing their industrial applications in fermentation.
• Hybrid yeasts, such as Saccharomyces pastorianus, are vital for lager beer production, a low-temperature fermentation process.

Purpose of the Study:

• To experimentally investigate the specific role of mtDNA in determining temperature tolerance in Saccharomyces hybrids.
• To explore whether the source of mtDNA (parental strain) can be used to modulate the temperature preferences of hybrid yeast strains.
• To provide evidence for the mitochondrial climactic adaptation hypothesis in yeast species.

Main Methods:

• Construction and analysis of synthetic and industrial hybrids between Saccharomyces cerevisiae and Saccharomyces eubayanus.
• Experimental testing of temperature tolerance in these hybrid strains under controlled conditions.
• Comparison of temperature tolerance across hybrids with different mitotypes (mtDNA origins).

Main Results:

• The temperature tolerance of Saccharomyces hybrids directly correlates with the mtDNA-donating parent.
• Modifying the mitotype of hybrid strains effectively altered their temperature preferences.
• Identical nuclear backgrounds with different mtDNA showed distinct temperature tolerances.

Conclusions:

• mtDNA is a significant determinant of temperature tolerance in Saccharomyces hybrids.
• Mitotype manipulation offers a strategy to tailor yeast strains for specific fermentation temperatures.
• This research supports the mitochondrial climactic adaptation hypothesis and highlights mtDNA's historical influence on fermented beverages like lager beer.