Constraints in temperature adaptation reinforce differences in thermal niche between mesophilic and psychrotolerant Bacillus cereus group species

Experimental evolution has demonstrated that mesophilic microbes readily adapt to increases in temperature. However, many microbes are psychrotolerant and resistant to cold, which is associated with physiological specializations, suggesting constraints in thermal adaptation. We hypothesized that constraints would limit adaption differently in a mesophilic species (B. thuringiensis) compared to its psychrotolerant relative B. mycoides – with adaptation at cooler temperatures and adaptation at higher temperatures being constrained in each species respectively. To test this hypothesis, we imposed 140 generations of selection at temperatures at and below the optimum for productivity for both species, conducting competition fitness assays, thermal profiling via thermal performance curves and SNP variant analysis to determine the changes that occurred during experimental evolution. 
The data and code enclosed is that used to create each figure in the paper and the raw data generated in t..., , # Constraints in temperature adaptation reinforce differences in thermal niche between mesophilic and psychrotolerant Bacillus cereus group species

Access this dataset on Dryad DOI:10.5061/dryad.w9ghx3g2c

## Introduction

Experimental evolution has demonstrated that mesophilic microbes readily adapt to increases in temperature. However, many microbes are psychrotolerant and resistant to cold, which is associated with physiological specializations, suggesting constraints in thermal adaptation. We hypothesized that constraints would limit adaption differently in a mesophilic species (B. thuringiensis) compared to its psychrotolerant relative B. mycoides – with adaptation at cooler temperatures and adaptation at higher temperatures being constrained in each species respectively. To test this hypothesis, we imposed 140 generations of selection at temperatures at and below the optimum for productivity for both species. The fitness and thermal performance of evolved bacteria showed ancestra...,