The Arabidopsis thaliana mobilome

Transposable elements are powerful motors of genome evolution yet a comprehensive knowledge of the "mobilome" and its impact at the species level is lacking. Here, using re-sequencing data for 210 Arabidopsis thaliana accessions taken from across the globe, we show recent transposition activity for half of the ~330 transposable element families present in this plant species. Furthermore, we uncover extensive variation in the composition of the mobilome between accessions. Genome-wide association studies reveal a complex genetic architecture, involving the transposable elements themselves and diverse gene loci, notably that encoding the DNA methyltransferase MET2. Most transpositions occur near or within genes and affect their expression and DNA methylation status. Remarkably, loci controlling adaptive responses to the environment such as pathogen resistance (NLR) and flowering time (FLC) are the most frequent transposition targets. These findings demonstrate the richness of the mobilome at the species level and its importance in nature as a recurrent provider of rare mutations with large effects