Comparative Mitogenomics And Phylogenetics Of Acaridae

Objective: Acaridae mites belong to Arachnida,Acari,Acariformes,Astigmatina,Acaroidea.As one of the most common storage mites,Acaridae mites are important pests of various stored products,posing potential threats to preserved foods.Accurate classification and identification of mites are necessary for formulating appropriate control metods.The taxonomy and phylogeny have long been fraught with controversy,due to the classification of Acaridae mites mostly based on morphological characteristics and DNA barcoding.Complete mitochondrial genomes have characteristics of an entire genome,small size and faster evolution rate.They provide reliable molecular markers for species identification and phylogenetic analysis,have been widely used in research of Acaridae species.However,there are still many problems in the recent research of mitochondrial genomics and phylogenetic relationships within Acaridae,such as whether there were t RNAs lacking,comparative mitochondrial genomics is helpful to evaluate suitable molecular markers,and the lack of several groups data posing challenges for investigation of phylogenetic relationships.Hence,it is of great significance to sequence complete mitochondrial genomes of more Acaridae species,which will accerate exploreing the feathure of complete mitochondrial genomes and phylogenetic relationships within this family.Methods: The complete mitogenomes of Tyrophagus fanetzhangorum,Scatoglyphus polytrematus,Thyreophagus entomophagus,Acarus siro and Aleuroglyphus ovatus were sequenced using an Illumina Hiseq sequencer.The programs such as MITOS,ARWEN,RNAfold and Mfold were used to annotate and analysis these mitogenomes.Meanwhile,mitogenome feature analysis and evolution rate calculation of eight Acaridae species were performed based on bioinformatics software,such as MEGA X and Dna SP.Phylogenetic analyses were conducted using Bayesian inference(BI)methods and maximum likelihood(ML)methods.ResultsThe complete mitogenomes of T.fanetzhangorum,S.polytrematus,T.entomophagus,A.siro and A.ovatus were 14257 bp,13966 bp,14056 bp,14402 bp and 14321 bp,respectively.Both contained a typical set of 13 PCGs,22 t RNAs,2 r RNAs,and 1 control region.The five mitogenomes had a high AT content,and the gene orders were assumed to be the gene arrangement of a possible common ancestor of astigmatid mites.Only trn K showed the typical cloverleaf in these two species,and 21 of the 22 t RNAs appeared to lack the D-and/or T-arms.In Acaridae species,mitogenomes have highly conserved gene size and order,and codon usage.Among Acaridae mites,most PCGs were found to be under purifying selection,implying that most PCGs might have evolved slowly.Our findings showed that atp8 evolving most rapidly,while cox1 and cox3 evolving most slowly.In astigmatina,the Ka/Ks values of the same genes in different superfamilies showed large differences.The ML and BI analyses based on a nucleotide dataset from 13 mitochondrial PCGs inferred the similar topology.Within the Astigmatina,the monophyly of Histiostomatoidea and Glycyphagoidea were observed.Phylogenetic analysis rejected the monophyly of Acaroidea,because Suidasiidae and Lardoglyphidae were not grouped with Acaridae.The monophyly of Acaridae were confirmed in this study.ConclusionThe complete mitogenomes of Acaroidea were all closed circular molecules containing 37 genes and 1 CR with the same gene arrangement.Our results do not support the loss of t RNA genes in Acaridae.In Acaroidea,the atp8 gene with the highest Ka/Ks value of 13 PCGs,which might represent a suitable marker for species identification.The cox1 and cox3 genes with the lowest Ka/Ks value could be used as barcoding markers for phylogenetic analyses.The phylogenetic relationships found in our study show that mitogenomes may be one of the most useful molecular markers for inferring phylogenetic relationships in Acaridae.The monophyly of Acaroidea was rejected,the phylogenetic analysis proposed a review of the current Acaroidea classification system.Furthermore,Acaridae was recovered as a monophyletic group.