Genome, genetic evolution, and environmental adaptation mechanisms of Schizophyllum commune in deep subseafloor coal-bearing sediments

To understand the genomic evolution and adaptation strategies of fungi to subseafloor sedimentary environments, we de novo assembled the genome of Schizophyllum commune strain 20R-7-F01 isolated from similar to 2.0 km-deep, similar to 20-millionyearsago (Mya) coal-bearing sediments. Phylogenomics study revealed a differentiation time of 28-73 Mya between this strain and the terrestrial type-strain H4-8, in line with sediment age records. Comparative genome analyses showed that FunK1 protein kinase, NmrA family, and transposons in this strain are significantly expanded, possibly linking to the environmental adaptation and persistence in sediment for over millions of years. Re-sequencing study of 14 S. commune strains sampled from different habitats revealed that subseafloor strains have much lower nucleotide diversity, substitution rate, and homologous recombination rate than other strains, reflecting that the growth and/or reproduction of subseafloor strains are extremely slow. Our data provide new insights into the adaptation and long-term survival of the fungi in the subseafloor sedimentary biosphere.

Automated summary

By studying the genomic evolution and adaptation strategies of fungi in subseafloor sedimentary environments, we found differentiation between the strain studied and terrestrial type-strain, possibly due to the sediment age. The strain potentially adapted and persisted in sediment for millions of years through the expansion of specific protein kinases, families, and transposons. Additionally, subseafloor strains had slow growth and reproduction rates.