The Construction of Full-Length cDNA Library for Otodectes cynotis

Transcriptome Analysis of Otodectes cynotis in Different Developmental Stages

The mite Otodectes cynotis is distributed worldwide and parasitism the ear canals of cats and dogs, causing otitis externa. Molecular biology of O. cynotis is poorly understood, with only a few genes being deposited in public databases. In the present study, we aimed to perform transcriptome analysis of O. cynotis using SMRT and Illumina sequencing of RNA from different development stages. SMRT-Seq of O. cynotis demonstrated 5,431 final transcripts, including 406 long non-coding RNAs and 2,698 differentially expressed genes (DEGs), including 1,357 up-regulated genes and 1,341 down-regulated genes between adult mites and nymph/larva. A total of 397 putative allergen genes were detected, 231 of which were DEGs. Among them, 77 were homologous of known mite allergens. The expression level of allergen genes hints at the pathogenicity of mites in different life stages, and the protein interaction network analysis could identify possible key genes in the pathogenic mechanism. Intriguingly, Gene Ontology analysis showed that most of the (DEGs) were associated with the terms hydrolase activity and proteolysis. Kyoto Encyclopedia of genes and genomes (KEGG) analysis identified drug metabolism-cytochrome P450 signal pathway as one of the top pathways. SMRT-Seq of the full-length transcriptome of O. cynotis was performed first, and a valuable resource was acquired through the combination analysis with the Illumina sequencing data. The results of our analyses provide new information for further research into Otodectes cynotis.

De Novo RNA-seq and Functional Annotation of Haemaphysalis longicornis

PURPOSE

Haemaphysalis longicornis (Neumann) is a hematophagous tick widely distributed in northern China. It not only causes enormous economic loss to animal husbandry, but also as a vector and reservoir of various zoonotic pathogens, it spreads natural focal diseases, such as severe fever with thrombocytopenia syndrome, seriously threatening human health. Lack of transcriptomic and genomic data from H. longicornis limits the study of this important medical vector.

METHODS

The engorged female H. longicornis from Gansu, China, was used for RNA extraction, de novo RNA-seq, functional annotation, and ORF prediction.

RESULTS

As a result, 53.09 million clean reads (98.88%) with a GC content of 54.29% were obtained. A total of 65,916 Unigenes were assembled, of which 34.59% (23,330) were successfully annotated. Of these Unigenes, 22,587 (34.27%) were annotated to species by NCBI non-redundant protein (nr). Ixodes scapularis, Limulus polyphemus, Parasteatoda tepidariorum, Stegodyphus mimosarum, and Metaseiulus occidentalis were the top BLAST hit species, accounting for 47.23%, 9.58%, 4.11%, 3.50%, and 2.69%, respectively. A total of 29,182 ORFs were predicted, and 35 complete ORFs for functional genes were identified, including ORFs involved in digestion (14), stress responses (8), anticoagulation (3), reproduction (3), antimicrobial (2), drug resistance (2), movement (2), autophagy (1), and immunity (1), respectively. The Unigene ORFs encoding cathepsin and heat shock proteins were further analyzed phylogenetically.

CONCLUSION

De novo RNA-seq and functional annotation of H. longicornis were successfully completed for the first time, providing a molecular data resource for further research on blood-sucking, pathogen transmission mechanisms, and effective prevention and control strategies.