Differences in the fitness effects of traded resources shape traits and persistence in multi-mutualist communities
Data files
Jan 30, 2026 version files 37.73 KB
-
README.md
2.90 KB
-
Yeast_MMC_evolution_data.xlsx
34.83 KB
Abstract
Mutualistic interactions, where species reciprocally benefit from each other, are crucial for ecosystem stability and biodiversity. These interactions often involve species that experience different fitness effects for the traded resources or services. Because mutualisms rely on positive feedback between partners, such asymmetries can strongly influence evolutionary outcomes. Differences in fitness effects create divergent selective pressures, shaping trait evolution and determining the persistence of mutualisms. The strength of these effects can also vary depending on the availability of traded resources from other sources. Despite their importance, the evolutionary role of fitness asymmetries in mutualism has received little attention, beyond recognizing that some species may be more dependent on their partners than others. This study investigates how asymmetry in the fitness effects of a traded resource influences the persistence and phenotypic trait evolution of species in multi-mutualist guilds. To test this, we constructed synthetic multi-mutualist communities by combining reproductively isolated and genetically modified strains of Saccharomyces cerevisiae that engage in a nutritional mutualism by trading adenine and lysine. One guild of four strains cannot produce lysine but overproduces adenine while the other guild cannot produce adenine but overproduces lysine. Lysine overproducers survive periods of low adenine better than adenine overproducers survive low lysine. Over a four-week evolution experiment we observed that strain persistence was strongly influenced by the availability of external resources. Communities in media containing traded resources supported the survival of all strains, whereas obligate conditions led to a significant extinction, especially for adenine overproducers. We observed distinct evolutionary trajectories of traits under obligate versus supplemented conditions. Phenotypic assays revealed that costs and benefits evolved differently depending on the essentiality of the traded resource and nutrient supplementation. These results demonstrate that asymmetries in the fitness effects of traded resources can influence evolutionary outcomes, species persistence, and community stability in multi-mutualist communities.
Dataset DOI: 10.5061/dryad.kwh70rzjq
Description of the data and file structure
Files and variables
File: Yeast_MMC_evolution_data.xlsx
Description: Synthetic multi-mutualist communities were constructed by combining reproductively isolated and genetically modified strains of Saccharomyces cerevisiae that engage in a nutritional mutualism by trading adenine (AdeOP) and lysine (LysOP). Mutualistic strain persistence and key traits associated with the production of traded resources, resource use, and population growth were tested after four weeks of evolution.
There are four worksheets:
1) Proportion_persistence
Variables
- Week- Each value corresponds to the week in which strain persistence was tested.
- Media- Strains evolved in two environments; Obligate=no external resources; High= external resources present.
- Strain_id- Strain member identified by a strain number
- OP_type- Overproducer strain, AdeOP or LysOP
- N- Indicates the number of communities strain was absent from in that week.
- Y- Indicates the number of communities strain was present in that week.
- sample_n- starting total number of communities containing the respective strain
- Prop_pers- Proportion of persistence of the strain
2) Retained_strains_in_communities
Variables
- Media- Strains evolved in two environments; Obligate=no external resources; High= external resources present.
- Number- Indicates how many strains were present within a given guild at that time point, out of a total of four possible members.
- OP_type- type of overproducing strain, AdeOP overproduces adenine, LysOP overproduces lysine
- Persisted- Percentage of persistence of the strain
3) AdeOP_phenotyping and 4) LysOP_phenotyping
Variables
- Deepwell- 48-well plate used for the experiment
- Person- Who performed the experiment. A: Anne E. Curé; R: Renuka Agarwal
- Community- combinations of 4x4 AdeOPs and LysOPs
- Media-Strains evolved in two environments; Obligate=no external resources; High= external resources present
- Strain_id- Strain member identified by a strain number
- t0_prop- Proportion of strain persisted after 0 hrs of starvation
- t48_prop- Proportion of strain persisted after 48 hrs of starvation
- t72_prop- Proportion of strain persisted after 72 hrs of starvation
- t96_prop- Proportion of strain persisted after 96 hrs of starvation
- t120_prop- Proportion of strain persisted after 120 hrs of starvation
- t24_real_OD- Optical density at 24 hrs; Resource use efficiency
- growth_rate- ((LN(OD @ 6hrs/OD @ 4hrs))/2
- real_OP_OD- Optical density of overproducing strain
- real_test_OD- Optical density of test strain
- OD_corrected- real_test_OD/real_OP_OD
NA- missing data code