1 SCIENTIFIC REPORTS | 7: 4408 | DOI:10.1038/s41598-017-04833-z www.nature.com/scientificreports Mitogenomic analyses support the recent division of the genus Orthotrichum (Orthotrichaceae, Bryophyta) Jakub Sawicki 1,2 , Vítězslav Plášek 2 , Ryszard Ochyra 3 , Monika Szczecińska 1 , Monika Ślipiko 1 , Kamil Myszczyński 1 & Tomasz Kulik 1 A recently presented taxonomical arrangement of the moss genus Orthotrichum Hedw. s.l. substantially changed the traditional view of the taxon that had been accepted throughout the twentieth century. This paper provides the results of mitogenomic studies that strongly support the new taxonomical concept. Comparative analyses presented in this study confirmed the stable structure of moss mitogenomes. Moreover, 17 complete mitogenome sequences were used to identify the major evolutionary groups, including 11 newly sequenced ones, for this study. The analysis of mitochondrial hotspots revealed intron 4 of the cox1 gene to be the most variable non-coding region. The most variable protein-coding genes in the tribe Orthotricheae were ccmFC and tatC. The intergenic and intronic hotspots of Orthotrichum s.l. identified in the present study do not correspond to those described in vascular plant mitogenomes. e genera Nyholmiella Holmen & Warncke, Lewinskya F. Lara, Garilleti & Goffinet and Orthotrichum Hedw. represent a group of approximately 167 species widely distributed subcosmopolitan mosses of the family Orthotrichaceae 1–13 . Species of these genera are found in several biomes, with the exception of deserts and wet tropical forests. Orthotrichum species are predominantly epiphytes that grow on tree trunks and branches, and they are less oſten found in saxicolous habitats at high altitudes, up to 5,000 m a.s.l. 14 . e subdivision within this genus has been the subject of continuing debate since the late 19th century. Specific taxa have been repeatedly included in and removed from Orthotrichum s.l. in an attempt to identify infrageneric taxa, including subgenera and sections. e history of Orthotrichum s.l. taxonomic classification was described in detail by Lewinsky and Hedenäs 14, 15 , and several phylogenetic analyses revealed that the genus was polyphyletic 16–19 . Nuclear and chlo- roplastic molecular markers were used to identify four groups within Orthotrichum s.l. with variable reproduc- tive systems and localization of stomata 17, 18 . Based on these molecular results, a new taxonomical arrangement was proposed for the group, in which Orthotrichum s.l. was divided into the genera Lewinskya, Nyholmiella, Orthotrichum and Pulvigera Plášek, Sawicki & Ochyra 20, 21 . Moreover, previous research demonstrated that the Orthotrichum s.l. evolutionary and taxonomic debate would not be resolved without the inclusion of species from the genus Ulota Mohr., which is closely related to the genus Lewinskya 16, 17, 19 . Ulota contains approximately 60 species 22 , more than half of which are found in the southern hemisphere. e genus is characterized by superficial stomata, highly differentiated basal leaf cells, crisped leaves, and a lack of brood bodies on the leaf lamina. Based on results of molecular studies 17, 19 , the dioecious U. phyllantha Brid. was transferred to the separate monospecific genus Plenogemma Plášek, Sawicki & Ochyra 20 . e genera mentioned above, together with Sehnemobryum Lewinsky-Haapasaari & Hedenäs and Stoneobryum D.H. Norris & H. Rob., are classified in the tribe Orthotricheae 17 . e genera of the tribe Orthotricheae comprise monoecious (Lewinskya, Orthotrichum s.s., Sehnemobryum, Ulota) and dioecious (Nyholmiella, Plenogemma, Pulvigera and Stoneobryum) taxa, which raises questions about the ancestry and monophyly of taxa representing the different sexual systems 14 . e tribe Zygodonteae, sister to 1 Department of Botany and Nature Protection, University of Warmia and Mazury, Plac Łódzki 1, 10-727, Olsztyn, Poland. 2 Department of Biology and Ecology, University of Ostrava, Chittussiho 10, 710 00, Ostrava, Czech Republic. 3 Laboratory of Bryology, Institute of Botany, Polish Academy of Sciences, Lubicz 46, 31-512, Kraków, Poland. Correspondence and requests for materials should be addressed to J.S. (email: jakub.sawicki@uwm.edu.pl) Received: 8 December 2016 Accepted: 22 May 2017 Published: xx xx xxxx OPEN