Transposons Hidden in <i>Arabidopsis thaliana</i> Genome Assembly Gaps and Mobilization of Non-Autonomous LTR Retrotransposons Unravelled by Nanotei Pipeline

oleh: Ilya Kirov, Pavel Merkulov, Maxim Dudnikov, Ekaterina Polkhovskaya, Roman A. Komakhin, Zakhar Konstantinov, Sofya Gvaramiya, Aleksey Ermolaev, Natalya Kudryavtseva, Marina Gilyok, Mikhail G. Divashuk, Gennady I. Karlov, Alexander Soloviev

Format: Article
Diterbitkan: MDPI AG 2021-12-01

Deskripsi

Long-read data is a great tool to discover new active transposable elements (TEs). However, no ready-to-use tools were available to gather this information from low coverage ONT datasets. Here, we developed a novel pipeline, nanotei, that allows detection of TE-contained structural variants, including individual TE transpositions. We exploited this pipeline to identify TE insertion in the <i>Arabidopsis thaliana</i> genome. Using nanotei, we identified tens of TE copies, including ones for the well-characterized ONSEN retrotransposon family that were hidden in genome assembly gaps. The results demonstrate that some TEs are inaccessible for analysis with the current <i>A. thaliana</i> (TAIR10.1) genome assembly. We further explored the mobilome of the <i>ddm1</i> mutant with elevated TE activity. Nanotei captured all TEs previously known to be active in <i>ddm1</i> and also identified transposition of non-autonomous TEs. Of them, one non-autonomous TE derived from (AT5TE33540) belongs to TR-GAG retrotransposons with a single open reading frame (ORF) encoding the GAG protein. These results provide the first direct evidence that TR-GAGs and other non-autonomous LTR retrotransposons can transpose in the plant genome, albeit in the absence of most of the encoded proteins. In summary, nanotei is a useful tool to detect active TEs and their insertions in plant genomes using low-coverage data from Nanopore genome sequencing.