De Novo Hybrid Assembly Unveils Multi-Chromosomal Mitochondrial Genomes in Species, Highlighting Genomic Recombination, Gene Transfer, and RNA Editing Events.

Biological invasions have been identified as the fifth cause of biodiversity loss, and their subsequent dispersal represents a major ecological challenge. The aquatic invasive species subsp. () and subsp. () are largely distributed in aquatic environments in North America and in Europe. However, they also present worrying terrestrial forms that are able to colonize wet meadows. To comprehend the mechanisms of the terrestrial adaptation of and , it is necessary to develop their genomic resources, which are currently poorly documented. We performed de novo assembly of the mitogenomes of and through hybrid assemblies, combining short reads (SR) and/or long reads (LR) before annotating both mitogenomes. We successfully assembled the mitogenomes of and into two circular molecules each, resulting in a combined total length of 711,578 bp and 722,518 bp, respectively. Notably, both the and molecules contained plastome-origin sequences, comprising 7.8% of the mitochondrial genome length. Additionally, we identified recombinations that were mediated by large repeats, suggesting the presence of multiple alternative conformations. In conclusion, our study presents the first high-quality mitogenomes of and , which are the only ones in the Myrtales order found as two circular molecules.