Gene duplication, horizontal gene transfer, and trait trade-offs drive evolution of postfire resource acquisition in pyrophilous fungi

Summary

Scientists studied fungi that thrive in burned soils after wildfires. They discovered these ‘fire-loving’ fungi have special genes for breaking down charcoal and acquiring nutrients, but this specialization comes at a cost—they grow more slowly than other fungi. The research identified three main evolutionary strategies these fungi use: duplicating useful genes, sexually reproducing to create genetic diversity, and occasionally borrowing genes from bacteria. These findings could help develop treatments to restore polluted or fire-damaged soils.

Background

Wildfires significantly alter soil carbon and nitrogen cycling while selecting for pyrophilous fungi that thrive in postfire environments. However, the genomic strategies and functional trade-offs that enable these fire-loving fungi to survive and persist postfire remain poorly understood.

Objective

To identify genomic adaptations and functional trade-offs in pyrophilous fungi that drive postfire colonization and persistence. The study tested hypotheses regarding evolutionary trade-offs between rapid growth, aromatic carbon degradation capacity, and nitrogen acquisition pathways.

Results

A dramatic trade-off was identified between fast growth and enrichment of aromatic carbon degradation genes. Gene duplication and somatic mutation were primary drivers in Eurotiales, while sexual recombination dominated in Pezizales and Agaricales. Cross-kingdom bacterial to fungal HGT contributed novel aromatic degradation genes in three species.

Conclusion

Trait trade-offs and multiple genome evolutionary strategies including gene duplication, sexual reproduction, and HGT are key drivers shaping pyrophilous fungal adaptation to postfire environments. These mechanisms enhance metabolic diversity for carbon and nitrogen acquisition while constraining growth rates, enabling ecological specialization in fire-disturbed ecosystems.
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