The Mitochondrial Genome Sequencing And Phylogenetic Analysis Of Cerambycidae Species(Insecta:Coleoptera)

Many species of Cerambycidae are important pests to all kinds of woody plants,crops and wood.The controversies on the classification of the higher order in Cerambycidae still existed.In recent years,the role of mitochondrial genomes in phylogenetic research has become increasingly important due to the development of sequencing technology.However,there are only 17 species of mitochondrial genomes in GenBank,and only 9 of them are complete.Compared with the larger species of insects,the existing mitochondrial genome data are also scarce.In this study,the mitochondrial genomes of 15 species in four subfamilies of Cerambycidae were studied and analysed.The phylogenetic tree of Cerambycidae based on mitochondrial genome was constructed,and the phylogenetic relationship among each subfamily and ethnic groups was discussed.The main findings are as follows:(1)Three complete mitochondrial genomes(Thyestilla gebleri?Anastrangalia sequensi?Aegosoma sinicum)and 12 almost complete genomes were obtained in this study,and 11 pairs of suitable universal primers were screened during sequencing.Anastrangalia sequensi and Aegosoma sinicum were the first species tested the complete mitochondrial genome sequence in Lepturinae and Prioninae,respectively.(2)The sequence characteristics of the Cerambycidae mitochondrial genome identified in this study and published in GenBank were comparative analysed,including base composition,gene rearrangement,gene overlap or gene spacer analysis and codon usage analysis.The results showed that the mitochondrial gene arrangement of beetle was compact,and only one tRNA(trnP)shift occurred in Vesperus conicicollis in 32 species of beetles.Th other genes were arranged in the same way as the ancestral insects.The whole length of complete mitochondrial genomes was between 15418bp(Batocera lineolata)and 16296bp(Anastrangalia sequensi),with a total AT content of 68.12%(Obrium sp.)to 79.02%(Batocera lineolata).The AT content of protein coding region was between 65.86%(Obrium sp.)and 78.21%(Leptura arcuata),and this content in Lamiinae and Lepturinae was higher than that of Cerambycinae and Prioninae.UUU(Phe),UUA(Leu)and AUU(Ile)were the first 3 most commonly used condons of 24 beetles.The UUA(Leu),which is the most widely used codon of Lamiinae and Lepturinae,is higher than the other two codons,and the third base of the codon has a significant AT bias.Most of start codons of protein coding genes were ATN type,a few use atypical start codons.The start codon of Nad1 gene was TTG except for Obrium sp..Stop codons were common TAR or incomplete T and TA.The intercellular base count of the genes showed that the ATP6-ATP8 region showed overlapping 7 bases.Except for Leptura arcuata,the largest interval was between Nadl-trnS2 and 15-23 bases.(3)The ML and BI tree was constructed based on the protein coding sequences,amino acid sequences and whole genome sequences of the available Cerambycidae mitochondrial genome,respectively.The phylogenetic tree constructed by different data and different methods had some deviations.The difference between ML and BI trees based on amino acid sequence was the smallest and the highest fit degree was found in morphological classification.Systemic tree based on amino acid sequences supports the uniqueness of Lamiinae,Prioninae,Lepturinae,Necydalidinae and Disteniinae.The Distoniinae and the narrowly defined Cerambycidae are sister groups,Necydalidinae and Lepturinae are sister groups,Obriini and Vesperinae,Prioninae and Cerambycinae(except Obriini)are sister groups.