The impact of transposable elements on tomato diversity

Tomatoes come in a multitude of shapes and flavors despite a narrow genetic pool. Here, we leveraged whole-genome resequencing data available for 602 cultivated and wild accessions to determine the contribution of transposable elements (TEs) to tomato diversity. We identified 6,906 TE insertions polymorphisms (TIPs), which result from the mobilization of 337 distinct TE families. Most TIPs are low frequency variants and disproportionately located within or adjacent to genes involved in environmental response.

In addition, we show that genic TE insertions tend to have strong transcriptional effects and can notably lead to the generation of multiple transcript isoforms. We also uncovered through genome-wide association studies (GWAS) ~180 TIPs associated with extreme variations in major agronomic traits or secondary metabolites. Importantly, these TIPs tend to affect loci that are distinct from those tagged by SNPs. Collectively, our findings suggest a unique and important role for TE mobilization in tomato diversification, with important implications for future breeding.