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The Mitochondrial Genome Of Atrijuglans Hetaohei Yang And Phylogenetic Status

Posted on:2017-02-25Degree:MasterType:Thesis
Country:ChinaCandidate:Q Q WangFull Text:PDF
GTID:2283330485979439Subject:Forest Protection
Abstract/Summary:PDF Full Text Request
The moth Atrijuglans hetaohei Yang is one of major pest to walnut fruits. The larval A. hetaohei can parasitie in the walnut fruits and results in the early fruit drop, which seriously affects the yield and the commercial value of walnut. However, the taxonomic status and the phylogenetic position of A. hetaohei still remain a controversial issue. The early scholars proposed A. hetaohei as a member of Heliodinidae(Yponomeutoidea), which has been widely used by Chinese scholars. While based on morphology, it was placed into Stathmopodinae(Gelechioidea).In order to identify the systematic status of A. hetahohei, in this study, the mitochodrial genome of Atrijuglans hetaohei Yang was sequenced by combining normal PCR and LA–PCR. After sequence assembly and annotation, we analysed the mtgenome of A. hetaohei in details, including the protein–coding genes, t RNA genes, rRNA genes and AT–rich region. At the same time, we compared its sequences with those of other lepidopterans available from GenBank and constructed the phylogenetic relationship among them. The conclusions of this study are summarized as follows:1. The complete mitochondrial genome of A. hetaohei Yang is 15 379 bp in length(GenBank: KT581634) and contains a typical set of 37 genes and a non–coding region(control region). The nucleotide composition of the mitogenome is biased toward A + T nucleotides(81.4%), and among these genes, the AT content is as follows: AT–rich region >rRNA>tRNA>PCGs.2. Except for cox1 gene that is initiated by CGA codon, all protein–coding genes start with ATN codons and end with the stop codon T, TA or TAA. The most frequent amino acids in the PCGs of A. hetaohei are Leucine, Isoleucine and Phenylalanine.3. All tRNAs have a typical clover–leaf secondary structure, except for trnS1, of which the DHU arm could not form a stable stem–loop structure. The prediction of rrnL and rrn S secondary structure of A. hetaohei shows that the stem areas were relatively conservative, and the sequence variation occurred in the loop region frequently.4. The A+T–rich region of A. hetaohei mitogenome is totally 363 bp in length, which habors some typical structure characteristics, such as microsatellite–like repeat(AT)9 and the poly–T stretch.5. Phylogenetic analyses of the complete mitochondrial genome sequences and of the amino acid sequences for 13 mitochondrial protein–coding genes among related species support the view that A. hetaohei is more closely related to the Gelechioidea than Yponomeutoidea.This study firstly described and analyzed the complete nucleotide sequence of the mitogenome of A. hetaohei, including the gene order, the nucleotide composition of PCGs and the secondary structures of tRNA genes. Additionally, this study contributes to more molecular information of lepidopteran phylogeny and to clarify the taxonomic status of the A. hetaohei.
Keywords/Search Tags:Atrijuglans hetaohei Yang, Mitochondrial genome, Gene content, RNA secondary structure, Phylogenetic analysis
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