云南松毛虫线粒体基因组全序列测定和分析

Sequencing and Analysis of Complete Mitochondrial Genome of Dendrolimus houi Lajonquiere (Lepidoptera: Lasiocampidae)

[目的]测定和分析了云南松毛虫线粒体基因组特征,从线粒体基因组水平探究鳞翅目蛾类昆虫高级阶元的系统发育关系。[方法]采用Illumina HiSeq测序方法测定了云南松毛虫线粒体全基因组序列,参考鳞翅目昆虫已知线粒体基因组的全序列对其各基因进行定位和注释。采用tRNA Scan-SE 2.0在线预测云南松毛虫线粒体基因组tRNA基因的二级结构。基于线粒体全基因组的蛋白编码序列构建了鳞翅目13个科32种蛾类昆虫的系统发育树和松毛虫属近缘种间的系统发育树。[结果]结果显示云南松毛虫线粒体基因组全长15 443 bp,包括13个蛋白质编码基因,22个tRNA基因,2个rRNA基因和一段长度为321 bp的A+T富含区,无基因重排,存在较高的A+T含量(80.0%)。13个蛋白编码基因中除了ND2和COX1,其余均以ATN做为起始密码子。9个蛋白编码基因共享相同的终止密码子TAA(ND2、ATP8、ATP6、COX3、ND5、ND4L、ND6、CYTB和ND1),其他4个基因的终止密码子都是残缺的,COX1、COX2、ND4以T为终止密码子,ND3以TA为终止密码子。22个tRNA基因中,除了tRNA^Ser(AGN)由于缺少DHU臂无法构成三叶草结构,其余T均为典型的三叶草结构。整个线粒体结构与鳞翅目中目前已得到的其他昆虫线粒体基因组结构一致。[结论]系统发育分析结果显示,云南松毛虫与思茅松毛虫是完全不同的近缘种,与其他松毛虫亲缘关系也较远,云南松毛虫与6种近缘种的系统发育关系为:(((((油松毛虫+文山松毛虫)+赤松毛虫)+落叶松毛虫)+(思茅松毛虫+云南松毛虫))+家蚕)。鳞翅目蛾类各科之间的系统发育关系为:((((((((毒蛾科+灯蛾科)+夜蛾科)+舟蛾科)+(尺蛾科+(蚕蛾科+(天蛾科+大蚕蛾科))))+枯叶蛾科)+(螟蛾科+草螟科))+卷蛾科)+蝙蝠蛾科)。

[Objective] To identify and analyze the mitochondrial genome of Dendrolimus houi Lajonquiere, and to study the higher-level phylogenetic relationship of Lepidoptera moths based on the mitochondrial genome.[Method] The Illumina Hiseq technique was chosen to sequence the purified mitochondrial DNA of D.houi .The genes were located and annotated based on the known complete mitochondrial genomes of Lepidopteran species.The tRNA Scan-SE 2.0 was used to predict the secondary structure of the tRNA genes online.Based on the PCGs of the whole nucleotide sequences of mitochondrial genome, the phylogenetic trees of 32 species from 12 families of Lepidoptera moths and the phylogenetic trees of the relative species of the Dendrolimus were reconstructed.[Result] The results indicated that the complete mitochondrial genome of D.houi is 15 443 bp in length, including 13 protein-coding genes (PCGs), 22 tRNA genes, 2 rRNA genes and a 321 bp A+T-rich region, without gene rearrangement, and showed a higher A+T content (80.0%).All these PCGS except for ND2 and COX1, used ATN as the start codon.Nine PCGs shared the same stop codon TAA, and the stop codons of the other four genes were all defective.COX1, COX2, and ND4 used T as the stop codon and ND3 used TA as the stop codon.Among the 22 tRNA genes, tRNASer (AGN) lacked the DHU arm and could not form a clover structure, while the remaining tRNAs were typical clover structures.The mitochondrial structure was consistent with other insect's mitochondrial genome structures currently available in Lepidoptera.[Conclusion] The phylogenetic analysis indicates that D.houi and D.kikuchii are completely different relatives, and the relationship between D.houi and other Dendrolimus species is also far away.The phylogenetic relationship is:((((( D.tabulaeformis + D.punctatus wenshanensis)+ D.spectabilis + D.superans)+( D.houi + D.kikuchii))+ Bombyx mori ).The phylogenetic relationship between the families of Lepidoptera is:((((((((Lymantriidae + Arctiidae)+ Noctuidae)+ Notodontidae)+(Geometriidae +(Bombycidae +(Sphingidae + Satumiidae))))+ Lasiocampidae)+(Pyralidae + Cramnidae))+ Tortricidae)+ Hepialidae).