Geography and environmental pressure are predictive of class-specific radioresistance in black fungi

Black fungi are among the most resistant organisms to ionizing radiation on Earth. However, our current knowledge is based on studies on a few isolates, while the overall radioresistance limits across this microbial group and the relationship with local environmental conditions remain largely undetermined. To address this knowledge gap, we assessed the survival of 101 strains of black fungi isolated across a worldwide spatial distribution to gamma radiation doses up to 100 kGy. We found that intra and inter-specific taxonomy, UV radiation, and precipitation levels primarily influence the radioresistance in black fungi. Altogether, this study provides insights into the adaptive mechanisms of black fungi to extreme environments and highlights the role of local adaptation in shaping the survival capabilities of these extreme-tolerant organisms. Representative strains of black fungi tested in this study. Colony aspect of Exophiala xenobiotica CCFEE6194 (Eurotomycetes); colony aspect of Cryomyces antarcticus MNA-CCFEE515 (Dothideomycetes); colony growth of E. xenobiotica CCFEE5811 after gamma irradiation at 0, 0.5, 1, 2, and 3 kGy (from left to right panel); colony growth of Friedmanniomyces endolithicus MNA-CCFEE5001 after gamma irradiation at 0, 5, 15, 30, and 50 kGy (from left to right panel).image

Automated summary

This study evaluated the survival of 101 strains of black fungi from worldwide locations to high doses of gamma radiation, and found that intra and inter-specific taxonomy, UV radiation, and precipitation levels are the primary factors influencing the radioresistance of black fungi.