Deflecting the parasitic paradigm: new insights into mutualistic transposons in plant genomes

Inherited transposable elements (TEs) embedded in genomes have an incomparable potential for large-effect mutagenesis. Notwithstanding that transposable elements can be destructive when mobile, it is undeniable that some beneficial effects arise as well. From a population-level perspective, de novo genetic variation arising from TE transposition endows species with increased potential to colonize and thrive in extremely diverse environments. With an emphasis on plant genomes, this review provides an overview of recent insights into functional transpositions and the mechanisms behind them. We will discuss the underappreciated application prospects of mobile elements as prominent endogenous mutagens through recent evidence of transposition-induced phenotypic variation. These novel findings suggest a shift away from the view of TEs as solely parasitic entities and advocate for a more mutualistic role.