Mitogenome characterization and phylogeny of Neohydatothrips gracilipes (Thripidae: Sericothripinae)

Thrips are tiny, fringe-winged insects acting as serious pests and vectors of Tospoviruses in agroecosystems. The second complete mitogenome of the subfamily Sericothripinae, Neohydatothrips gracilipes (14,999 bp), was generated by the next-generation sequencing method. It consists of 37 genes with two putative control regions along with a positive AT skew and a negative GC skew. Most of the tRNAs showed a typical clover-leaf secondary structure except trnS1, trnV, which lack the DHU arm. PCGs based analyses revealed that cox1 is the most conserved gene, while nad6 is the most variable gene. Moreover, the ratios of non-synonymous to synonymous substitution rates indicated that all PCGs were under purifying selection. Phylogeny revealed that N. gracilipes is a close relative of N. samayunkur and nested within the subfamily Thripinae. The gene order of both congeneric members (samayunkur and gracilipes) is similar and shows 27 transpositions and 8 inverse transpositions with the ancestor. The gene blocks B (atp8-atp6) and H (nad2-trnW) are recovered as conserved, whereas gene block G (rrnl-trnV) conserved in all the members of suborder Terebrantia except Sericothripinae. The gene atp8 was located on the major stand in thrips mitogenomes, except in the members of the subfamily Sericothripinae, in which atp8 is flipped. To resolve the nested position of the Sericothripinae in phylogeny, additional data on mitogenomes based on the genera Sericothrips and Hydatothrips is required.