Oliveira Jordana I N, Lane Catrina, Mugambi Ken, Yildirir Gokalp, Nicol Ariane M, Kokkoris Vasilis, Banchini Claudia, Dadej Kasia, Dettman Jeremy, Stefani Franck, Corradi Nicolas
Department of Biology, University of Ottawa, Ottawa, ON K1N 6N5, Canada.
Agriculture and Agri-Food Canada, Ottawa Research and Development Centre, Ottawa, ON K1A 0C6, Canada.
Genome Biol Evol. 2025 Mar 6;17(3). doi: 10.1093/gbe/evaf038.
Transposable elements are repetitive DNA sequences that excise or create copies that are inserted elsewhere in the genome. Their expansion shapes genome variability and evolution by impacting gene expression and rearrangement rates. Arbuscular mycorrhizal fungi are beneficial plant symbionts with large, transposable element-rich genomes, and recent findings showed these elements vary significantly in abundance, evolution, and regulation among model strains. Here, we aimed to obtain a more comprehensive understanding of transposable element function and evolution in arbuscular mycorrhizal fungi by investigating assembled genomes from representatives of all known families. We uncovered multiple, family-specific bursts of insertions in different species, indicating variable past and ongoing transposable element activity contributing to the diversification of arbuscular mycorrhizal fungi lineages. We also found that transposable elements are preferentially located within and around candidate effectors/secreted proteins, as well as in proximity to promoters. Altogether, these findings support the role of transposable elements in promoting the diversity in proteins involved in molecular dialogs with hosts and, more generally, in driving gene regulation. The mechanisms of transposable element evolution we observed in these prominent plant symbionts bear striking similarities to those of many filamentous plant pathogens.
转座元件是可切除或产生拷贝并插入基因组其他位置的重复DNA序列。它们的扩增通过影响基因表达和重排率塑造了基因组的变异性和进化。丛枝菌根真菌是有益的植物共生体，具有庞大的、富含转座元件的基因组，最近的研究结果表明，这些元件在模式菌株中的丰度、进化和调控存在显著差异。在这里，我们旨在通过研究所有已知科的代表菌株的组装基因组，更全面地了解丛枝菌根真菌中转座元件的功能和进化。我们发现不同物种中存在多个家族特异性的插入爆发，这表明过去和正在进行的转座元件活动各不相同，这有助于丛枝菌根真菌谱系的多样化。我们还发现，转座元件优先位于候选效应子/分泌蛋白内部和周围，以及启动子附近。总之，这些发现支持了转座元件在促进与宿主进行分子对话的蛋白质多样性方面的作用，更普遍地说，在驱动基因调控方面的作用。我们在这些重要的植物共生体中观察到的转座元件进化机制与许多丝状植物病原体的机制有着惊人的相似之处。
