Mitogenome Of The Bamboo Pest,the Notobitus Montanus(Hemiptera:Coreidae) And Phylogenetic Analysis Of The Coreoidea

Notobitus montanus Hsiao 1963,a major pest of bamboo and a member of the subfamily Coreoinae in the superfamily Coeoidea,can cause serious damage to bamboo resources.Mitogenomes play an important role in revealing the evolutionary selection and reconstruction of phylogenetic relationships in insects.There are no mitogenome data to support the phylogenetic status of the genus Notobitus of Coreoidea.The conclusions of previous studies on the phylogenetic relationships of the general family Coreoidea based on mitogenomic data are inconsistent,and the small amount of data containing species with existing mitochondrial genomes does not provide new insights or add stable and credible evidence for the evolutionary relationships of this general family.Studies on the evolutionary relationships within Coreoidea using cladistic analysis,as well as recent results based on ultraconserved element loci,mitogenomes,and nuclear genes,are inconsistent in their conclusions regarding the relationships among families,subfamilies,and genera.To address these issues,this study sequenced the mitogenome of N.montanus using second-generation sequencing technology.Based on the results of 13 protein-coding genes(PCGs)were consistent with the phylogenetic relationship of Coreoidea on the basis mitochondrial and nuclear genomes,the phylogenetic relationships within Coreoidea were consistent with the increase of species.The main research results are as follows:The mitogenome of N.montanus was 16209 bp in size with a base composition of 42.26%A,30.54%T,16.54%C,and 10.65%G.Like other species in the family Coreidae,it has a high A+T content.The nucleotide composition of the minority strand(N-strand)shows a negative AT-skew values ranging from-0.396(nad4L)to-0.336(nad5)and a positive GC-skew ranging from 0.222(nad4)to 0.333(nadl).The majority of the protein-coding genes(PCGs)on the majority strand(J-strand)have opposite AT-and GC-skew values to those on the N-strand,except for cox1(-0.021),which has a negative AT-skew value.The AT-skew values of the remaining PCGs on the J-strand are positive,ranging from 0.008(nad5)to 0.203(atp8),and the GC-skew values are negative,ranging from-0.310(atp8)to-0.056(cox1).The total AT-and GC-skew values of the 13 PCGs in N.montanus are similar to those of other Coreidae species.The AT-skew values of the eight tRNA genes on the N-strand are positive,ranging from 0.020(trnF and trnP)to 0.184(trnH),and the GC-skew values are negative,ranging from-0.600(trnH)to-0.125(trnF).The AT-skew values of the 14 tRNA genes on the J-strand are positive,ranging from 0.020(trnT)to 0.174(trnR),and the GC-skew values are both positive and negative,ranging from-0.167(trnE)to 0.333(trnI).The AT-skew values of the two rRNA genes are positive,with values of 0.229(rrnL)and 0.118(rrnS),and the GC-skew values are negative,with values of-0.294(rrnL)and-0.333(rrnS).The AT-skew value of the non-coding control region(D-loop)is positive(AT-skew=0.081),and the GC-skew value is negative(GC-skew=-0.328).Codon usage analysis indicates that the most frequently used codons have A or T at the third position.The amino acid usage pattern of N.montanus is consistent with that of the Coreoidea,with higher levels of leucine 2,phenylalanine,isoleucine,tyrosine,methionine,and asparagine.The Ka/Ks ratios of all 13 PCGs are<1,indicating that they are evolving under purifying selection pressure.Nad5 and cox1 have the lowest and highest levels of purifying selection,respectively.Correlation analysis shows a positive correlation between evolutionary rate and A+T content.No tandem repeat sequences were found in the D-loop of N.montanus,but Coreidae species with tandem repeat sequences have been found from group 0 to group 3.The phylogenetic tree indicates that the systematic relationships within the superfamily Coreoidea are as follows:(Stenocephalidae+(Rhopalidae+(Alydidae+Coreidae))),where Alydidae and Rhopalinae are not monophyletic.The relationships among the subfamilies are(((((Alydinae+Pseudophloeinae)+Hydarinae)+Micrelytrinae)+Coreinae)+Rhopalinae).Hydarinae and Pseudophloeinae within Coreidae are closely related to Alydidae.The relationships among genera within Coreinae are(Manocoreus+(Enoplops+Cletus))+((Acanthocoris+(Notobitus+Cloresmus))+(Leptoglossus+(Mictis+(Pseudomictis+(Anoplocnemis+(Molipteryx+(Notopteryx+Cletomorpha))))))).In this study,the topology of the phylogenetic tree based on the 13 PCGs is consistent with the one based on the combined mitochondrial and nuclear genes,but not with the one based on the super-conserved elements or the combination of the 13 PCGs and 2 rRNAs.It appears that the systematic relationships within Coreoidea are complex and may require re-evaluation and modification.The mitogenome information of 30 Coreoidea species,including the N.montanus used in this study,can be used to reveal the evolution of species within Coreoidea.In summary,this study identified and obtained the first mitochondrial whole genome of the genus Notobitus and compared it with those of other species in the superfamily Coreoidea,and reconstructed the phylogeny of the superfamily Coreoidea,which provides a profile of the mitochondrial genome of the mangosteen Notobitus montanus and a reference for phylogenetic analysis of the superfamily Coreoidea.