RT Journal Article
SR Electronic
T1 Transposable element over-accumulation in autopolyploids results from relaxed purifying selection and provides variants for rapid local adaptation
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 686584
DO 10.1101/686584
A1 P. Baduel
A1 L. Quadrana
A1 B. Hunter
A1 K. Bomblies
A1 V. Colot
YR 2019
UL http://biorxiv.org/content/early/2019/06/28/686584.abstract
AB Polyploidization is frequently associated with increased transposable element (TE) content. However, what drives TE dynamics following whole genome duplication (WGD) and the evolutionary implications remain unclear. Here, we leveraged whole-genome resequencing data of ∼300 individual Arabidopsis arenosa plants, a well characterized natural diploid-autotetraploid species, to address these questions. Based on 43,176 polymorphic TE insertions we detected in these genomes, we demonstrate that relaxed purifying selection rather than transposition bursts is the main driver of TE over-accumulation after WGD. Furthermore, the increased pool of TE insertions in tetraploids is especially enriched within or near abiotic and biotic stress response genes. Notably, we uncovered one such insertion in a major flowering-time repressor gene and found that the resulting allele is specific to the rapid-cycling tetraploid lineage that colonized mainland railways. Together, our findings indicate that tetrasomy by itself leads to an enhanced tolerance to accumulating genic TE variants, some of which can potentially contribute to local adaptation.