The Green Tetrahymena utriculariae n. sp. (Ciliophora, Oligohymenophorea) with Its Endosymbiotic Algae (Micractinium sp.), Living in Traps of a Carnivorous Aquatic Plant.
The genus Tetrahymena (Ciliophora, Oligohymenophorea) probably represents the best studied ciliate genus. At present, more than forty species have been described. All are colorless, i.e. they do not harbor symbiotic algae, and as aerobes they need at least microaerobic habitats. Here, we present the morphological and molecular description of the first green representative, Tetrahymena utriculariae n. sp., living in symbiosis with endosymbiotic algae identified as Micractinium sp. (Chlorophyta). The full life cycle of the ciliate species is documented, including trophonts and theronts, conjugating cells, resting cysts and dividers. This species has been discovered in an exotic habitat, namely in traps of the carnivorous aquatic plant Utricularia reflexa (originating from Okavango Delta, Botswana). Green ciliates live as commensals of the plant in this anoxic habitat. Ciliates are bacterivorous, however, symbiosis with algae is needed to satisfy cell metabolism but also to gain oxygen from symbionts. When ciliates are cultivated outside their natural habitat under aerobic conditions and fed with saturating bacterial food, they gradually become aposymbiotic. Based on phylogenetic analyses of 18S rRNA and mitochondrial cox1 genes T. utriculariae forms a sister group to Tetrahymena thermophila.
Limnological Station, Department of Plant and Microbial Biology, University of Zurich, Kilchberg, 8802, Switzerland.
Gianna
G
Pitsch
Institute of Botany CAS, Section of Plant Ecology, Třeboň, 379 82, Czech Republic.
Lubomír
L
Adamec
Limnological Station, Department of Plant and Microbial Biology, University of Zurich, Kilchberg, 8802, Switzerland.
Sebastian
S
Dirren
Institute for Zoology, General Ecology, Biocenter, University of Cologne, Cologne, 50674, Germany.
Frank
F
Nitsche
Biology Centre CAS, Institute of Hydrobiology, České Budějovice, 370 05, Czech Republic.
Karel
K
Šimek
Biology Centre CAS, Institute of Hydrobiology, České Budějovice, 370 05, Czech Republic.|Faculty of Science, University of South Bohemia, České Budějovice, 370 05, Czech Republic.
Dagmara
D
Sirová
Limnological Station, Department of Plant and Microbial Biology, University of Zurich, Kilchberg, 8802, Switzerland.
Thomas
T
Posch
D000818:Animals; D001483:Base Sequence; D000460:Chlorophyta / Q000469:parasitology*; D016798:Ciliophora / Q000145:classification* / Q000378:metabolism / Q000502:physiology; D016054:DNA, Protozoan; D004463:Ecology; D017753:Ecosystem; D008018:Life Cycle Stages; D008928:Mitochondria / Q000235:genetics; D016802:Oligohymenophorea / Q000145:classification*; D010100:Oxygen / Q000378:metabolism; D010802:Phylogeny; D010944:Plants / Q000469:parasitology*; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D013559:Symbiosis / Q000502:physiology*; D013768:Tetrahymena / Q000145:classification* / Q000166:cytology / Q000302:isolation & purification / Q000378:metabolism; D016808:Tetrahymena thermophila / Q000145:classification / Q000235:genetics; D064028:Tracheophyta / Q000469:parasitology
D016054:DNA, Protozoan; D012337:RNA, Ribosomal, 18S; D010100:Oxygen

Utricularia
; Ciliates; Tetrahymenida; life cycle; mixotrophy; symbiotic algae