Comparative Analysis of Eight Mitogenomes of Bark Beetles and Their Phylogenetic Implications.

Huicong Du,Zhen Zhang,Jiaxing Fang,Xiangbo Kong,Xia Shi,Sufang Zhang,Fu Liu,Chunmei Yu

doi:10.3390/insects12100949

Abstract

Simple SummaryMany bark beetles are destructive pests in coniferous forests and cause extensive ecological and economic losses worldwide. Comparative studies of the structural characteristics of mitogenomes and phylogenetic relationships of bark beetles can improve our understanding of mitogenome evolution. In this study, we sequenced eight mitogenomes of bark beetles. Our results show that the use of start and stop codons, the abundance of amino acids, and the relative frequency of codon use are conserved among the eight bark beetles. Different regions of tRNA exhibit different degrees of conservatism. Together with the analysis of evolutionary rates and genetic distance among bark beetle species, our results reveal phylogenetic relationships among bark beetles of the subfamily Scolytinae.Many bark beetles of the subfamily Scolytinae are the most economically important insect pests of coniferous forests worldwide. In this study, we sequenced the mitochondrial genomes of eight bark beetle species, including Dendroctonus micans, Orthotomicus erosus, Polygraphus poligraphus, Dryocoetes hectographus, Ips nitidus, Ips typographus, Ips subelongatus, and Ips hauseri, to examine their structural characteristics and determine their phylogenetic relationships. We also used previously published mitochondrial genome sequence data from other Scolytinae species to identify and localize the eight species studied within the bark beetle phylogeny. Their gene arrangement matched the presumed ancestral pattern of these bark beetles. Start and stop codon usage, amino acid abundance, and the relative codon usage frequencies were conserved among bark beetles. Genetic distances between species ranged from 0.037 to 0.418, and evolutionary rates of protein-coding genes ranged from 0.07 for COI to 0.69 for ND2. Our results shed light on the phylogenetic relationships and taxonomic status of several bark beetles in the subfamily Scolytinae and highlight the need for further sequencing analyses and taxonomic revisions in additional bark beetle species.

Highlights

IntroductionBark beetles (Coleoptera: Curculionidae: Scolytinae) feed mainly on the phloem and xylem of their hosts (e.g., pines, spruces, larches), severely affecting forest ecology and reducing forestry production [1,2]
All mitochondrial genomes of each species consisted of thirteen protein-coding genes (PCGs), twenty-two tRNAs, and two rRNAs
Most of the sequences in the control region are located between the rrnS and trnI genes, and some of them are divided into two segments by the trnI gene [40,41]

Summary

Introduction

Bark beetles (Coleoptera: Curculionidae: Scolytinae) feed mainly on the phloem and xylem of their hosts (e.g., pines, spruces, larches), severely affecting forest ecology and reducing forestry production [1,2]. Because they bore cryptically under the bark and into the wood, they are difficult to detect at the onset of the threat, resulting in many bark beetle species becoming established outside their original range [3]. Because bark beetles are both highly damaging and difficult to control, many researchers have studied the developmental trends of bark beetle species/populations using molecular markers [6,7,8,9,10]. With the development of DNA sequencing technology, the mitochondrial genomes of more and more insect species are being sequenced [19,20,21]

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Results

Conclusion