Data and scripts accompanying the paper "Elevated substitution rates and increased purifying selection associated with thermophily in fungi"

Abstract Understanding the genomic consequences of thermal adaptation in fungi is crucial, as rising global temperatures are expected to increase negative impacts on food safety and human health. The family Chaetomiaceae contains a large number of thermophilic fungal taxa, but previous studies have reported inconsistent optimal growth temperature (OGT) assessments for the same strains. Here we applied a standardized laboratory approach to measure OGT across 19 Chaetomiaceae species and used a phylogenomic approach to examine correlations between OGT, rates of genome evolution, and strength of purifying selection. Compared to mesophiles, thermophilic fungi showed faster nucleotide substitution rates while having stronger purifying selection on conserved orthologs. We hypothesize that the observed elevated substitution rates are linked to high growth rates, as thermophilic fungi grew significantly faster than mesophilic ones. Our results show that selective pressures may act at different temperature thresholds for distinct genomic characteristics. Genome size was lower at OGT ≥ 35°C compared to mesophilic species, while GC content did not show a large difference between mesophiles and thermotolerant species, but increased in thermophilic species with an OGT ≥ 45°C.