RT Journal Article SR Electronic T1 Genome rearrangements and megaplasmid loss in the filamentous bacterium Kitasatospora viridifaciens are associated with protoplast formation and regeneration JF bioRxiv FD Cold Spring Harbor Laboratory SP 629089 DO 10.1101/629089 A1 Karina Ramijan A1 Zheren Zhang A1 Gilles P. van Wezel A1 D. Claessen YR 2019 UL http://biorxiv.org/content/early/2019/05/07/629089.abstract AB Filamentous Actinobacteria are multicellular bacteria with linear replicons. Kitasatospora viridifaciens DSM 40239 contains a linear 7.8 Mb chromosome and an autonomously replicating plasmid KVP1 of 1.7 Mb. Here we show that lysozyme-induced protoplast formation of the multinucleated mycelium of K. viridifaciens drives morphological diversity. Characterization and sequencing of an individual revertant colony that had lost the ability to differentiate revealed that the strain had not only lost most of KVP1 but also carried lesions in the right arm of the chromosome. Strikingly, the lesion sites were preceded by insertion sequence elements, suggesting that the rearrangements may have been caused by replicative transposition and homologous recombination between both replicons. These data indicate that protoplast formation is a stressful process that can lead to profound genetic changes.Repositories Genomic sequence data for strain B3.1 has been deposited in the NCBI SRA database under accession code SAMN11514356.