2026/06/16 by Julianna Paulsen, Stephen Sharrett, Devin Mumey +7 · 1 voice
Agricultural and Biological Sciences · Biochemistry, Genetics and Molecular Biology · #Mycorrhizal Fungi and Plant Interactions #Plant Pathogens and Fungal Diseases #Yeasts and Rust Fungi Studies
paper · doi:10.1093/g3journal/jkag153
openalex created_date 2025/10/10 · openalex publication_date 2026/06/16 · openalex updated_date 2026/07/25
Transposable elements (TEs) have the potential to drive genome evolution by introducing mutations and causing structural instability and chromosomal rearrangements, particularly under conditions like environmental or genetic stress. In this study, we generated 18 new long-read based metagenomically assembled reference genomes for lichenized fungi, which form obligate mutualistic symbioses with algae or cyanobacteria. We used the new genomes and 10 publicly available genomes to investigate the relationships between species traits (i.e., dominant reproductive mode, distribution size, and generation length) and the abundance and spatial distribution of TEs using a phylogenetic comparative framework. We found that species with smaller distribution sizes and longer generation lengths had a higher genomic DNA transposon load. Specifically, their genomes were enriched with Rolling Circle transposons, which contradicts previous research that has identified high proportions of retrotransposons in rare species. Disproportionate distributions of TEs in rare and range-restricted species may disrupt genomic stability, decrease fitness, and be reflective of species experiencing a greater degree of stress. Conversely, greater TE activity may be an important source of novel genetic diversity in isolated populations with limited gene flow. Further research is needed to understand the potential mechanisms driving TE proliferation in rare species' genomes, and if TE content is predictive of increased extinction risk.