Characterization Of The Complete Mitochondrial Genomes Of Euthrix Laeta And Trabala Vishnou Guttata And Phylogenetic Analyses

Euthrix laeta and Trabala vishnou guttata are belonging to Lasiocampidae,Lepidoptera.Their larvae feed on important economic plants,which are two important economic pests.Currently,the studies about two lappet moths is just in morphology and biology.This study measured using PCR and sequencing technology for obtaining two lappet moths mitochondrial genome(mitogenome)sequences,and analyze the gene structure,composition,arrangement characteristics;The phylogenetic trees are constructed basing on E.laeta,T.vishnou guttata and 35 species of lepidopteran insects mitogenome protein-coding genes of amino acid and nucleotide sequences and two ribosomal RNA gene sequences.The conclusions are as follows:1.The mitogenome of E.laeta and T.vishnou guttata are15,368 bp and 15,281 bp.GenBank accession number are KU870700 and KU884483,and AT content are 80.19% and 80.87%,respectively.Both have 37 genes(13 protein-coding genes(PCGs),22 tRNA genes,2 r RNA genes)and 1 AT rich region.The previous three tRNA genes arrangement of two lappet moths are typical tRNAMet-tRNAIle-tRNAGln between AT rich region and ND2,the remaining genes are consistent with that of other insects.Two lappet moths mitogenome have 18 and 11 intergenic region(total length are 192 bp and 149 bp),9 and 12 genetic overlap region(total length are 26 bp and 49 bp),respectively.Relative to the overlap regions,the intergenic regions are bigger,the length is longer,the biggest spacer(70 bp and 54 bp)are located in between tRNAGln and ND2,and the longest overlap region are located in tRNALeu(UCN)and 16 s rRNA.2.Except COI gene begins with CGA codon among E.laeta and T.vishnou guttatamitogenome PCGs,the rest PCGs are begin with ATN(ATA,ATC,ATG,ATT)codon,the terminator codons are TAA or separate T base.Two lappet moths have 13 PCGs,total length are 11,213 bp and 11,211 bp,respectively.The AT content are 78.72% and 79.40%,encoding 3726 and 3727 amino acids.The higher codon usage frequency of two lappets moth are UUU(F),AUU(I)and UUA(L),which is resulting in the most corresponding three kinds of amino acids(Phe,Ile and Leu),and the number of Cys is minimum.3.The total length of E.laeta and T.vishnou guttata mitogenome tRNA gene are 1,468 bp and 1,452 bp,AT content is at the range of 81%,the length of every gene is 60-70 bp.Except tRNASer(AGN)missingdihydrouracil arm,other forms a typical cloverleaf strucyure.There are 20 and 16 base mismatch(U-G)appearing in two lappet moths mitogenome tRNA genes,respectively,at dihydrouracil arm,antisense codon arm,amino acids accepted arm and T ? C arm.The length of E.laeta mitogenome r RNA gene(total AT content is 84.67%)are 1390 bp and 776 bp,and that of T.vishnou guttata are 1354 bp and 778 bp with a total AT content of 85.23%.4.The AT rich region of two lappet moths locate between 12 s rRNA and tRNAMet with length of 372 bp and 383 bp.The AT content are as high as 91.40% and 91.40%.In the two lappet moth AT enrichment region has "ATAGA + Poly T" and Poly T,Poly A structure.In E.laeta mitochondria AT rich region appears two microsatellite structure:(TA)6 and(TA)7,but no this relative sructure in T.vishnou guttata mitochondria AT rich region,that is inferred that the above several structure may be related to mitochondrial genome replication,transcription regulation.5.The NJ tree,MP tree,ML and BI tree are established basing on 13 PCGs amino acid sequence,13 PCGs,and 13 PCGs +2 rRNA gene nucleotide sequences.The most credible BI tree displays genetic relationships among every Lepidopteran superfamily:((((((Bombycoidea + Geometroidea)+(Lasiocampidae+Noctuoidea))+ Pyraloidea)+(Papilionoidea + Hesperioidea))+ Tortricoidea)+ Yponomeutoidea)+ Hepialoidea.The reason why gene rearrangement appearing in Hepialoidea insects is that the same characteristics as lepidopteran ancestor insects genes,and in the periphery of phylogenetic trees.A typical phylogenetic relationship of papilio and hesperid:(((((Lycaenidae + Lycaenidae)+ Nymphalidae)+ Pieridae)+ Hesperiidae)+ Papilionidae)is found in many studies.Four kinds of phylogenetic tree show the taxonomic relation:((((Sphingidae + Bombycidae)+ Saturniidae)+ Geometridae)+ Lasiocampidae),which supports the conclusion that Lasiocampidae is separated from Bombycoidea.