Blinded by the lights? Re-examining the adaptive role of transposable elements in plants with population genomics

Transposable elements (TEs) are ubiquitous components of the genome whose mobility can be triggered by environmental stress and influenced by genotype-environment interactions. In plants, TEs constitute a substantial proportion of the genome and frequently cause large-effect mutations that impact gene regulation, methylation, and phenotype expression. These characteristics have recently positioned TEs as potential drivers of rapid local adaptation. However, this perspective is not always integrated with the broader understanding of fitness effects and neutral processes. Despite numerous associations between TEs and fitness-related traits, clear cases directly linking TE insertion, phenotype, and fitness in natural populations-i.e., genuine examples of local adaptation-remain rare in plants. Emerging population-genomic evidence presents a more complex picture: while some TE insertions may facilitate adaptation or rapid responses to environmental change, most are selected against and act as deleterious, selfish elements. The evolutionary dynamics of TEs are further modulated by genome architecture, reproductive system, and ecological context, underscoring their system-specific behavior. In this opinion piece, I argue that generalizing about the significance of TEs in local adaptation in plants is fraught with complexity and risks oversimplification. As sequencing technologies advance, integrating theoretical population genetics with large-scale comparative analyses and simulations across a wider range of species will be essential to more fully characterize the dynamics of TEs.