title: Back to monoxeny: Phytomonas nordicus descended from dixenous plant parasites.
abstract: The trypanosomatid Phytomonas nordicus parasitizing the predatory bug Troilus luridus was described at the twilight of the morphotype-based systematics. Despite its monoxenous life cycle, this species was attributed to the dixenous genus Phytomonas due to the presence of long twisted promastigotes and development of flagellates in salivary glands. However, these characteristics were considered insufficient for proving the phytomonad nature of the species and therefore its description remained virtually unnoticed. Here, we performed molecular phylogenetic analyses using 18S ribosomal RNA (rRNA) gene and region containing internal trascribed spacers (ITS) 1 and 2 and convincingly demonstrated the affinity of P. nordicus to the genus Phytomonas. In addition, we investigated its development in the salivary glands. We argue that in many aspects the life cycle of monoxenous P. nordicus resembles that of its dixenous relatives represented by tomato-parasitizing Phytomonas serpens.
authors.affiliation: Zoological Institute of the Russian Academy of Sciences, Universitetskaya nab. 1, St. Petersburg 199034, Russia.
authors.forename: Alexander O
authors.initials: AO
authors.lastname: Frolov
authors.affiliation: Zoological Institute of the Russian Academy of Sciences, Universitetskaya nab. 1, St. Petersburg 199034, Russia.
authors.forename: Marina N
authors.initials: MN
authors.lastname: Malysheva
authors.affiliation: Life Science Research Centre, Faculty of Science, University of Ostrava, Chittussiho 10, 710 00 Ostrava, Czech Republic; Biology Centre, Institute of Parasitology, Czech Academy of Sciences, Branišovská 31, 370 05 České Budějovice, Czech Republic.
authors.forename: Vyacheslav
authors.initials: V
authors.lastname: Yurchenko
authors.affiliation: Zoological Institute of the Russian Academy of Sciences, Universitetskaya nab. 1, St. Petersburg 199034, Russia; Life Science Research Centre, Faculty of Science, University of Ostrava, Chittussiho 10, 710 00 Ostrava, Czech Republic. Electronic address: kostygov@gmail.com.
authors.forename: Alexei Yu
authors.initials: AY
authors.lastname: Kostygov
mesh_terms: D000818:Animals; D021903:DNA, Ribosomal Spacer / Q000235:genetics; D020062:Heteroptera / Q000469:parasitology*; D010802:Phylogeny; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D013045:Species Specificity; D014351:Trypanosomatina / Q000145:classification* / Q000235:genetics*
chemical_list: D021903:DNA, Ribosomal Spacer; D012337:RNA, Ribosomal, 18S
keywords: Evolution; Monoxenous lifestyle; Phytomonas; Ultrastructure