Extrachromosomal circular DNA and structural variants highlight genome instability in Arabidopsis epigenetic mutants

Nat Commun. 2023 Aug 28;14(1):5236. doi: 10.1038/s41467-023-41023-0.


Abundant extrachromosomal circular DNA (eccDNA) is associated with transposable element (TE) activity. However, how the eccDNA compartment is controlled by epigenetic regulations and what is its impact on the genome is understudied. Here, using long reads, we sequence both the eccDNA compartment and the genome of Arabidopsis thaliana mutant plants affected in DNA methylation and post-transcriptional gene silencing. We detect a high load of TE-derived eccDNA with truncated and chimeric forms. On the genomic side, on top of truncated and full length TE neo-insertions, we detect complex structural variations (SVs) notably at a disease resistance cluster being a natural hotspot of SV. Finally, we serendipitously identify large tandem duplications in hypomethylated plants, suggesting that SVs could have been overlooked in epigenetic mutants. We propose that a high eccDNA load may alter DNA repair pathways leading to genome instability and the accumulation of SVs, at least in plants.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis* / genetics
  • DNA Transposable Elements / genetics
  • DNA, Circular
  • Genomic Instability / genetics
  • Humans
  • RNA Interference


  • DNA Transposable Elements
  • DNA, Circular