Mitochondrial genome of Phalantus geniculatus (Hemiptera: Reduviidae): trnT duplication and phylogenetic implications

Reduviidae is the second largest family of Heteroptera and most of them are important natural enemies of agricultural and forest pests. Most of the sequenced mitochondrial (mt) genomes in this family have the typical gene arrangement of insects and encode 37 coding genes (13 protein-coding genes, 22 tRNA genes and two rRNA genes). In the present study, we sequenced the mt genome of Phalantus geniculatus from the subfamily Peiratinae through high-throughput sequencing and encountered the duplication of tRNA genes for the first time in this subfamily. We identified 23 tRNA genes, including 22 tRNAs commonly found in insect mt genomes and an extra trnT (trnT2), which has high sequence similarity (96.9%) to trnT1. The presence of a "pseudo-trnP" in the non-coding region between trnT1 and trnT2 supports the hypothesis that the presence of an extra trnT can be explained by the tandem duplication-random loss (TDRL) model. Phylogenetic results inferred from mt genome sequences supported a sister relationship between Phymatinae and the remaining sampled subfamilies, as well as a paraphyletic Reduviinae. The present study highlights the utility of mt genomes in the phylogenetic study of Reduviidae based on the large scale taxon sampling in the future.