Mitochondrial genome of Brachystomella parvula (Collembola: Brachystomellidae)

Abstract

We reported one mitochondrial genome of Brachystomella parvula assembled from Illumina sequencing and discussed its phylogenetic position within Poduromorpha. Our mitochondrial assembly has a length of 15,002 bp, consisting of 36 genes (13 protein-coding genes, 21 transfer RNA genes, and two ribosomal RNA genes) with tRNA^Ser unsuccessfully assembled. Its gene composition and order were similar to most reported invertebrates. The overall base composition is 36.6% for A, 34.8% for T, 16.8% for C, and 11.8% for G.

Brachystomella Ågren, 1903, the largest genus of Brachystomellidae Stach, 1949 (Poduromorpha), includes 75 species worldwide (Bellinger et al. 1996‒2019). However, there is few information on its systematic position within Poduromorpha. Earlier studies (D’Haese 2002; D’Haese 2003; Greenslade et al. 2011) indicated that Brachystomella (Brachystomellidae) was sistered with Neanuridae. To date, only a few mitochondrial and ribosomal sequences have been reported for Brachystomellidae (NCBI, accessed 2019 Oct 28). To further advance evolutionary studies for Brachystomellidae, we sequenced the mitochondrial genome of Brachystomella parvula Schäffer, which is the first mitogenome sequence in Brachystomellidae.

In this study, the voucher specimen of B. parvula was collected in La Paloumère from 31-Herran, France (42.966°N, 0.868°E; NCBI BioSample accession SAMN11869185; specimen voucher number 31-377). Total genomic DNA was obtained from individual whole body using the QIAamp DNA Micro Kit (Qiagen, GmbH, Germany) and sequenced by NovaSeq 6000, generating 12.77 Gb of clean reads (NCBI SRA accession SRR9131240). The voucher specimen and extracted DNA were preserved at −20 °C in the Nanjing Agricultural University, China. The mitogenome was assembled with NOVOPlasty v2.7.0 (Dierckxsens et al. 2017), annotated with MitoZ v2.3 (Meng et al. 2019), and deposited in GenBank with the accession number MN660050.

Our mitochondrial assembly has a length of 15,002 bp, consisting of 36 genes (13 protein-coding genes, 21 transfer RNA genes, and two ribosomal RNA genes) with tRNA^Ser unsuccessfully assembled. Nine PCGs and 13 tRNA genes were located on the positive strand, while four PCGs (ND1, ND4, ND4L, and ND5), eight tRNA genes (tRNA^Leu, tRNA^Val, tRNA^Gln, tRNA^Cys, tRNA^Tyr, tRNA^Phe, tRNA^His, and tRNA^Pro) and two rRNA genes (l-rRNA and s-rRNA) were located on the reverse strand. In addition, the gene composition and order of were similar to most reported invertebrates except the lacking of trnS2 owing to assembly failure. The A + T content was 71.4% (36.6% for A, 34.8% for T, 16.8% for C, and 11.8% for G). For the 13 PCGs, nine of them (ND2, COX1, COX2, ATP6, COX3, ND3, ND5, ND4, and ND6) were terminated with TAA stop codon and two PCGs (ATP8 and ND4L) ended with TAG, and remaining two PCGs (ND1 and CYTB) ended with the incomplete stop codons (T and TA).

Amino acid sequences were aligned using MAFFT v7.407 (Katoh and Standley 2013) and trimmed with trimAl v1.4.1 (Capella-Gutiérrez et al. 2009) with the heuristic method ‘automated1’. The phylogeny was reconstructed using IQ-TREE v1.6.10 (Nguyen et al. 2015) with the partitioning method. Monophyly of Neanuridae was not recovered because B. parvula was clustered within Neanuridae (Figure 1).

Figure 1.

Maximum likelihood phylogenetic tree inferred from 13 PCGs. SH-aLRT and UFBoot support values are given on nodes.

Disclosure statement

No potential conflict of interest was reported by the authors.