The Complete Mitogenome of the Wood-Feeding Cockroach Cryptocercus meridianus (Blattodea: Cryptocercidae) and Its Phylogenetic Relationship among Cockroach Families.

Weijun Li,Yanli Che,Zongqing Wang

doi:10.3390/ijms18112397

Weijun Li, Yanli Che + Show 1 more

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https://doi.org/10.3390/ijms18112397

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Abstract

In this study, the complete mitochondrial genome of Cryptocercus meridianus was sequenced. The circular mitochondrial genome is 15,322 bp in size and contains 13 protein-coding genes, two ribosomal RNA genes (12S rRNA and 16S rRNA), 22 transfer RNA genes, and one D-loop region. We compare the mitogenome of C. meridianus with that of C. relictus and C. kyebangensis. The base composition of the whole genome was 45.20%, 9.74%, 16.06%, and 29.00% for A, G, C, and T, respectively; it shows a high AT content (74.2%), similar to the mitogenomes of C. relictus and C. kyebangensis. The protein-coding genes are initiated with typical mitochondrial start codons except for cox1 with TTG. The gene order of the C. meridianus mitogenome differs from the typical insect pattern for the translocation of tRNA-SerAGN, while the mitogenomes of the other two Cryptocercus species, C. relictus and C. kyebangensis, are consistent with the typical insect pattern. There are two very long non-coding intergenic regions lying on both sides of the rearranged gene tRNA-SerAGN. The phylogenetic relationships were constructed based on the nucleotide sequence of 13 protein-coding genes and two ribosomal RNA genes. The mitogenome of C. meridianus is the first representative of the order Blattodea that demonstrates rearrangement, and it will contribute to the further study of the phylogeny and evolution of the genus Cryptocercus and related taxa.

Highlights

Cryptocercus is a genus of woodroaches which occur in the high mountainous forests of temperate regions, in the Nearctic, Palaearctic, and Oriental Regions, and feed on rotten wood in logs [1,2,3]
The complete mitochondrial genome of C. meridianus is found to be 15,322 bp in size, which is smaller than that of C. relictus (15,373 bp) and C. kyebangensis (15,720 bp), with an asymmetric nucleotide composition (45.20% A, 16.06% C, 9.74% G, and 29.00% T) and an AT bias (74.2%) (Table 1)
AT content of the C. meridianus mitogenome (74.2%) is slightly higher than that of C. relictus (73.5%) and slightly lower than in C. kyebangensis (74.4%)

Summary

Introduction

Cryptocercus is a genus of woodroaches which occur in the high mountainous forests of temperate regions, in the Nearctic, Palaearctic, and Oriental Regions, and feed on rotten wood in logs [1,2,3]. Their distributional pattern has been strongly affected by palaeogeographic events that influenced their source tree hosts, such as the appearance of land bridges and the uplift of mountains [4]. Recent studies of phylogenetic relationships among Dictyoptera or Blattodea show that Cryptocercus is the sister group of termites [1,5,6,7,8]. They found that C. kyebangensis has a close relationship with C. relictus and these two Cryptocercus species share the same mitochondrial gene order

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