Public good‐driven release of heterogeneous resources leads to genotypic diversification of an isogenic yeast population

Abstract

Understanding the basis of biological diversity remains a central problem in evolutionary biology. Using microbial systems, adaptive diversification has been studied in (a) spatially heterogeneous environments, (b) temporally segregated resources, and (c) resource specialization in a homogeneous environment. However, it is not well understood how adaptive diversification can take place in a homogeneous environment containing a single resource. Starting from an isogenic population of yeast Saccharomyces cerevisiae, we report rapid adaptive diversification, when propagated in an environment containing melibiose as the carbon source. The diversification is driven due to a public good enzyme α‐galactosidase, which hydrolyzes melibiose into glucose and galactose. The diversification is driven by mutations at a single locus, in the GAL3 gene in the S. cerevisiae GAL/MEL regulon. We show that metabolic co‐operation involving public resources could be an important mode of generating biological diversity. Our study demonstrates sympatric diversification of yeast starting from an isogenic population and provides detailed mechanistic insights into the factors and conditions responsible for generating and maintaining the population diversity.

Empirical evidence of resource dependent evolution of payoff matrices inSaccharomyces cerevisiaepopulations

“…al . 22 performed laboratory evolution with an isogenic population of S. cerevisiae in melibiose. After evolving for 300 generations, the isogenic population comprised of cells in two distinct phenotypic states.…”

“…Haploid SC644 ( MATa MEL1ade1 ile trp1-HIII ura3-52 ) 22 was used as a cooperator and BY4741 was used as a cheater in Cases II and III.…”

Development of a genome-scale metabolic model for the lager hybrid yeast S. pastorianus to understand the evolution of metabolic pathways in industrial settings

“…2 ). In fact, S. pastorianus has been experimentally shown to be able to utilize melibiose as a carbon source for growth and fermentation, while S. cerevisiae is not able to support growth on this sugar alone ( 33 ), although some S. cerevisiae strains have been shown to metabolize melibiose to some extent ( 34 ). Hence, it is important to note that the growth and biomass yields of S. pastorianus on different sugar sources can be influenced by many factors, including the specific strain of yeast used, the composition of the culture media, and the environmental conditions of the fermentation process.…”

Development of a genome scale metabolic model for the lager hybrid yeastS. pastorianusto understand evolution of metabolic pathways in industrial settings

“…In medium containing melibiose as sole carbon source no biomass was detected using Yeast8, while our model was able to predict growth (Table 2, Figure 2). In fact, S. pastorianus has been experimentally shown to be able to utilize melibiose as a carbon source for growth and fermentation, while S. cerevisiae is not able to support growth on this sugar alone (Stewart, 2016), although some S. cerevisiae strains have been shown to metabolize melibiose to some extent (Mahilkar et al , 2022). Hence, it is important to note that the growth and biomass yields of S. pastorianus on different sugar sources can be influenced by many factors, including the specific strain of yeast used, the composition of the culture media, and the environmental conditions of the fermentation process.…”