Fungal heavy metal adaptation through single nucleotide polymorphisms and copy-number variation

Area of Science:

• Environmental Science
• Mycology
• Evolutionary Biology

Background:

• Human activities introduce pollutants, altering natural environments.
• The evolutionary responses of fungi to anthropogenic pollution are not well understood.
• Mycorrhizal fungi, like Suillus luteus, play crucial roles in ecosystems and may be impacted by soil contamination.

Purpose of the Study:

• To investigate adaptation in the mycorrhizal fungus Suillus luteus in response to soil heavy metal contamination.
• To identify genetic mechanisms enabling fungal survival in polluted environments.

Main Methods:

• Genome scans of Suillus luteus individuals from polluted and unpolluted Belgian soils.
• Analysis of single nucleotide polymorphism (SNP) divergence and gene copy-number variation.
• Identification of genes under selection in response to heavy metal exposure.

Main Results:

• No significant population structure was found based on soil type, indicating gene flow.
• Detected SNP divergence and gene copy-number variations associated with adaptation.
• Identified selection acting on variants in genes related to metal tolerance and detoxification (e.g., metal exclusion, storage, immobilization, reactive oxygen species detoxification).

Conclusions:

• Suillus luteus is exhibiting initial steps of adaptive divergence in response to heavy metal pollution.
• Genetic variation and selection on specific genes facilitate adaptation to contaminated soils.
• This study enhances understanding of local adaptation processes in fungi under environmental stress.