Characterization of the Complete Mitochondrial Genomes of Two Species with Preliminary Investigation on Phylogenetic Status of Zyginellini (Hemiptera: Cicadellidae: Typhlocybinae)

SIMPLE SUMMARY: Typhlocybinae currently is the second largest membracoid subfamily distributed worldwide and includes many important agricultural pests. The monophyly of Typhlocybinae has been supported by several recent analyses, but the relationships of its included tribes remain largely unexplored, particularly that of the phylogenetic relationship of Zyginellini and Typhlocybini. This study presented the annotated complete mitochondrial genome sequences of two zyginelline species, Limassolla sp. and Parazyginella tiani Gao, Huang and Zhang, 2012, and a comparative analysis of mitochondrial genomes within the Typhlocybini and Zyginellini. Typhlocybinae mitogenomes are highly conservative in overall organization, as have been found in some other Cicadellidae. The only unusual feature was found in the secondary structure of tRNAs, with the acceptor stem of trnR comprising only 5 or 6 bp in some species. This unusual feature was reported for the first time in Typhlocybinae. Phylogenetic analyses showed that the monophyly of tribe Zyginellini was not supported and should be treated as a synonym of Typhlocybini. Nevertheless, a broader analysis with a much larger sample of taxa is needed to confirm the present results. ABSTRACT: To explore the characteristics of mitogenomes and reveal phylogenetic relationships of the tribes of Zyginellini and Typhlocybini in Typhlocybinae, mitogenomes of two species of the Zyginellini, Parazyginella tiani and Limassolla sp., were sequenced. Mitogenomes of both species contain 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), two ribosomal RNA genes (rRNAs) and a large non-coding region (A + T-rich region). These characteristics are similar to other Membracoidea mitogenomes. All PCGs initiate with the standard start codon of ATN and terminate with the complete stop codon of TAA/G or with an incomplete T codon. All tRNAs have the typical clover-leaf structure, except trnS1 which has a reduced DHU arm and the acceptor stem of trnR is 5 or 6 bp in some species, an unusual feature here reported for the first time in Typhlocybinae. The A + T-rich region is highly variable in length and in numbers of tandem repeats present. Our analyses indicate that nad6 and atp6 exhibit higher evolutionary rates compared to other PCGs. Phylogenetic analyses by both maximum likelihood and Bayesian methods based on 13 protein-coding genes of 12 species of Typhlocybinae suggest that Zyginellini are paraphyletic with respect to Typhlocybini.