Stress Resistance of Saccharomyces cerevisiae Strains Overexpressing Yeast Polyphosphatases

Abstract

Inorganic polyphosphate (polyP) is an important factor in the stress resistance of microorganisms. The polyphosphate-overexpressing strains of yeast S. cerevisiae were used as a model for studying the inter-relationship between stress resistance and polyP level. We compared the polyP level and resistance to the oxidative, manganese, cadmium, and alkaline stresses in parent stain CRN and in strains overexpressing the four yeast polyphosphatases: Ppx1, Ppn1, Ppn2, and Ddp1. Strains overexpressing Ppx1, Ppn1, and Ppn2 have lower polyP content and the strain overexpressing Ddp1 has the same polyP content as the parent strain. The strains overexpressing Ppn1 and Ddp1 show higher resistance to peroxide and manganese. The strain overexpressing Ppx1 showed a decrease in peroxide resistance. The strain overexpressing Ppn2 was more resistant to alkaline and peroxide stresses. A similar increase in resistance to the manganese and peroxide stresses of strains overexpressing Ppn1 and Ddp1, which differ in polyP content, led to the conclusion that there is no direct relationship between polyP content and variations in this resistance. Thus, we speculate about the potential role of inositol pyrophosphates as signaling molecules in stress response.

Polyphosphate, Polyphosphatase and Stress Resistance of Knockout Mutants in the PPN1 and PPN2 Genes of Saccharomyces cerevisiae

“…The mutants lacking polyphosphatases Ppn1or Ppn2 showed both an increase in polyP chain length and an increase in resistance to manganese and peroxide. The Ppn1-overexpressing strain also showed higher resistance to both types of stress, while the Ppn2-overexpressing strain showed higher resistance to peroxide (Andreeva et al 2022). Apparently, the pathways leading to this increase are different in case of knockout mutation and overexpression of these genes.…”