The mitochondrial genome of Tetrahymena rostrata

Abstract

Tetrahymena rostrata is a ciliated protist which can parasitize the gray field slug, Deroceras reticulatum. Here, we report the sequence of the mitochondrial genome (mt genome) of a strain of T. rostrata that was isolated from the egg of D. reticulatum. Whole cell genomic DNA was sequenced using Illumina V R MiSeq and the mitochondrial DNA sequence reads were extracted and assembled. The resulting 47,235 bp assembly contained rRNAs, tRNAs, and 45 protein coding DNA sequences of which 21 encoded proteins of unknown function. Phylogenetic analysis showed T. rostrata clustered with Tetrahymena thermophila, Tetrahymena pigmentosa, Tetrahymena pyriformis, Tetrahymena paravorax, and Tetrahymena malaccensis.

Characterization and Comparative Analyses of Mitochondrial Genomes in Single-Celled Eukaryotes to Shed Light on the Diversity and Evolution of Linear Molecular Architecture

“…In the years since those seminal discoveries, more ciliate mitogenomes have been characterized, including 20 mitogenomes from species in the class Oligohymenophorea ( Tetrahymena pyriformis , T. thermophila , T. malaccensis , T. paravorax , T. pigmentosa , T. rostrata , Ichthyophthirius multifiliis , Uronema marinum , Paramecium caudatum , P. aurelia , P. tetraurelia , P. sexaurelia , P. multimicronucleatum , P. biaurelia , P. octaurelia , P. novaurelia , P. decaurelia , P. dodecaurelia , P. quadecaurelia , and P. jenningsi ) [ 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 ], eight mitogenomes of species in the class Spirotrichea ( Oxytricha trifallax , Laurentiella strenua , Stylonychia lemnae , Paraurostyla sp., Urostyla grandis , Pseudourostyla cristata , Euplotes minuta , and E. crassus ) [ 37 , 38 , 39 ], two mitogenomes in the class Heterotrichea ( Stentor coeruleus and Gruberia lanceolata ) [ 20 , 40 ], as well as seven hydrogenosomal genomes of anerobic ciliates ( Nyctotherus ovalis , Metopus contortus , Metopus es , Metopid sp., Heterometopus sp., Parablepharisma sp., and Muranothrix gubernata ) [ 41 , 42 , 43 ]. Ciliate mitogenomes are generally in size of 20–70 kb, with high A+T content (58.53% for N. ovalis ~81.51% for I. multifiliis ) and relatively large gene complements (20–30 protein-coding genes) [ 39 , 41 , 44 ].…”

Infection of Slugs with Theronts of the Ciliate Protozoan, Tetrahymena rostrata

“…T. rostrata isolate TRAUS was originally isolated from the egg of a D. reticulatum slug collected in Melbourne, Australia, in 2014 [ 17 ]. Cultures of T. rostrata were maintained at 20 °C in the dark in sterile PPYE medium (0.5% w/v proteose peptone (Oxoid, LP0085), 0.5% w/v yeast extract (Oxoid, LP0021) and 0.125% w/v glucose), and subcultures were performed fortnightly.…”

Intraspecies Variation in Tetrahymena rostrata

“…The mitogenomes of TRAUS and TR01 were characterised using 17,797,914 and 33,260,090 Illumina DNA short-read sequences, respectively [14]. Assembly of the mitochondrial DNA sequences of TRAUS resulted in a 47,235 nt contig (1,498,614 reads, average sequence depth of 4806 reads) and for TR01 a 47,310 nt contig (1,204,576 reads, average sequence depth of 3808 reads).…”

“…The Grey field slug, D. reticulatum is an invasive pest in many countries, including Australia where it has been present since at least the 1930s, probably longer [13]. T. rostrata was recently identified in Australia when it was isolated from the egg of a D. reticulatum slug and has been established in axenic culture [14]. The isolate, designated TRAUS, had the same morphological and phenotypic characteristics as the Spanish and Polish isolates.…”

“…The isolate, designated TRAUS, had the same morphological and phenotypic characteristics as the Spanish and Polish isolates. We recently reported the mitochondrial genome of TRAUS from Illumina libraries of whole cell DNA extracts [14]. While the TRAUS isolate grouped with Polish isolates TR1015 and TR1016 on the basis of the cox1 sequence data, the lack of whole mitochondrial genome sequence data for other T. rostrata isolates made detailed comparisons of taxonomic relationships challenging.…”