Brachionus paranguensis sp. nov. (Rotifera, Monogononta), a member of the L group of the Brachionus plicatilis complex

The genome of the euryhaline rotifer Brachionus paranguensis: Potential use in molecular ecotoxicology

Brachionus spp. rotifers have been proposed as model organisms for ecotoxicological studies. We analyzed the whole-genome sequence of B. paranguensis through NextDenovo, resulting in a total length of 106.2 Mb and 71 contigs. The N50 and the GC content were 4.13 Mb and 28%, respectively. A total of 18,501 genes were predicted within the genome of B. paranguensis. Prominent detoxification-related gene families of phase I and II detoxifications have been investigated. In parallel with other Brachionus rotifers, high gene expansion was observed in CYP clan 3 and GST sigma class in B. paranguensis. Moreover, species-specific expansion of sulfotransferase (SULTs) and gain of UDP-glucuronosyltransferases (UGTs) through horizontal gene transfer has been specifically found within B. plicatilis complex. This whole-genome analysis of B. paranguensis provides a basis for molecular ecotoxicological studies and provides useful information for comparative studies of the evolution of detoxification mechanisms in Brachionus spp.

Complete mitochondrial genome of the euryhaline monogonont rotifer Brachionus paranguensis (Rotifera, Brachionidae)

The two complete mitochondrial genomes were sequenced from the euryhaline monogonont rotifer Brachionus paranguensis. The mitochondrial genome sequences were 11,603 bp and 12,901 bp in size, and the gene order of 12 protein-coding genes (PCGs) were identical to those of the marine rotifer Brachionus plicatilis, but the positions of some tRNAs (e.g. tRNA-Ile, tRNA-Leu[TTA], tRNA-Phe, and tRNA-Leu[CTC]) of mitochondrial DNA I were different between B. paranguensis and B. plicatilis mitochondrial genomes. Of 12 PCGs, four genes (ND1, ATPase 6, ND5, and ND3) had incomplete stop codons. Furthermore, the start codon of ND4, ND5, and CO3 genes was ATT, while the start codon of other PCGs was ATG. The base composition of 12 PCGs in B. paranguensis mitochondrial genomes was 26.6% for A, 43.0% for T, 17.65% for C, and 12.75% for G, respectively.