Comparative Mitogenomics of Four Thripinae Species (Thysanoptera: Thripidae): Genome Architecture, Evolutionary Dynamics and Phylogeny

T he mitogenomes of four species, Arorathrips mexicanus (D.L. Crawford 1909), Bregmatothrips sinensis Wang & Tong 2016, Ctenothrips transeolinae Chen 1979, and Ernothrips longitudinalis Zhou, Zhang & Feng 2008, are annotated and characterised. These mitogenomes are AT biased, ranging from 75% to 79% with a positive AT skew (0.10 to 0.17) and a negative GC skew (-0.20 to -0.10). Most frequently used codons are ending with A/U. The synonymous and non-synonymous substitution analysis indicated that cox1 is the most conserved gene and nad6 is the most variable gene. Moreover, ENC-GC3 plots and neutrality plots indicated that atp8, cox2, nad3, nad4L lie above the predicted curve, suggesting that these genes are subjected to strong mutational constraints rather than natural selection. PR2 bias plots indicated that nad4, nad4L, nad5 exhibited bias of A over T and rest showing bias of T over A. Comparative analysis of the gene order of these species with ancestor identified five conserved gene blocks. The constructed ML phylogeny indicated that A. mexicanus and B. sinensis are in a sister relationship with the members of the Craspedothrips + Megalurothrips + Mycterothrips + Odontothrips, while C. transeolinae is with Taeniothrips tigris and Ernothrips longitudinalis with Thrips imaginis. Further, to explore the selection pressure on vector and non-vector species, more data on vector and non vector species are necessitated.