Romeijn, J. | bioRxiv Science

bioRxiv2025

Extensive horizontal transfer of transposable elements shape fungal mobilomes

Transposons impact eukaryotic genome size and evolution. Horizontal transfer of transposons (HTT) is important for their long-term persistence, but has only been systematically studied in animals, and thus the abundance, impact, and factors that shape HTTs in lineages outside animals is unknown. Fungi are at least as ancient and diverse as animals and are characterized by extensive genome size variation caused by transposons. Here, we screened 1,348 genomes across fungal biodiversity, genome sizes, and lifestyles to detect extensive HTTs, that generated on average 7% but up to 70% of the transposon content in some taxa. We in total identified at least 5,518 independent HTTs, mostly involving Tc1/Mariner DNA transposons. While the majority of HTTs occur between closely related taxa, irrespective of their lifestyles, HTTs were particularly common in Mucoromycotina, Sordariomycetes, Dothideomycetes, and Leotiomycetes. Importantly, species lacking fungal-specific defense mechanisms against transposons and those with gene-sparse and repeat-rich genomic compartments are involved in significantly higher number of HTTs, unveiling ecological and genomic factors shaping HTTs. Our findings thus illuminate the dynamic landscape of HTTs in fungi, providing the framework to further study the impact of HTTs on genome evolution and the processes that mediate transposon transfers within and between eukaryotic lineages.

evolutionary biology↗

bioRxiv2022

Exploring how the fast-slow pace of life continuum and cell size structure microorganism life history variation

Studying life history strategies in microorganisms can help predict their performance when complex microbial communities can be categorised into groups of organisms with similar strategies. Microorganisms are typically classified as copiotroph or oligotroph, but it has been proven difficult to generalise their life history strategies to broad lineages. Here we tested if the fast-slow continuum and reproductive strategy framework of macro-organismal life histories can be applied to microorganisms. We used demographic and energy budget data from 13 microorganisms (bacteria, fungi, a protist and a plant) to examine how generation time, survivorship, growth form, age at maturity, recruitment success, and net reproductive rate structure microbial life histories. We found that 79% of microorganism life-history variation fell along two uncorrelated axes. Like macro-organisms, we found a fast-slow pace of life continuum, including shorter-lived microorganisms at one end, and longer-lived microorganisms that mature later in life at the other. Also, like macro-organisms, we found a second, reproductive strategy axis, with microorganisms with greater lifetime reproductive success and decreased mortality at older age at one end, and microorganisms with the opposite characteristics at the other end. Microorganismal life history strategies did not covary proportionally to their shared evolutionary history. Thus, whereas this work suggests that the macro-organismal fast-slow continuum and reproductive strategy framework could be realistically applied to microorganisms, their life history processes cannot be inferred from patterns in taxonomic composition. Impact statementAnimals and plants show distinct differences in their pace of life: some have high reproduction and high mortality, others low. Here we show that microorganisms display similar such life history patterns, igniting future research on microbial life history strategies. Data summarySupplemental data, R code and MatLab code are deposited in Figshare at https://doi.org/10.6084/m9.figshare.16831543.v2 [27].

ecology↗