Transcriptome Analysis of <i>Dastarcus helophoroides</i> (Coleoptera: Bothrideridae) Using Illumina HiSeq Sequencing

<div><p>Background</p><p><i>Dastarcus helophoroides</i> is known as the most valuable natural enemy insect against many large-body longhorned beetles. The molecular mechanism of its long lifespan and reproduction makes it a unique resource for genomic research. However, molecular biological studies on this parasitic beetle are scarce, and genomic information for <i>D. helophoroides</i> is not currently available. Thus, transcriptome information for this species is an important resource that is required for a better understanding of the molecular mechanisms of <i>D. helophoroides</i>. In this study, we obtained transcriptome information of <i>D. helophoroides</i> using high-throughput RNA sequencing.</p><p>Results</p><p>Using Illumina HiSeq 2000 sequencing, 27,543,746 clean reads corresponding to a total of 2.48 Gb nucleotides were obtained from a single run. These reads were assembled into 42,810 unigenes with a mean length of 683 bp. Using a sequence similarity search against the five public databases (NR, Swiss-Prot, GO, COG, KEGG) with a cut-off E-value of 10⁻⁵ using Blastx, a total of 31,293 unigenes were annotated with gene description, gene ontology terms, or metabolic pathways.</p><p>Conclusions</p><p>To the best of our knowledge, this is the first study on the transcriptome information of <i>D. helophoroides</i>. The transcriptome data presented in this study provide comprehensive information for future studies in <i>D. helophoroides</i>, particularly for functional genomic studies in this parasitic beetle.</p></div

Overview of the transcriptome.

<p>Overview of the transcriptome.</p

Overview of <i>Dastarcus helophoroides</i> transcriptome sequence assembly.

<p>(A) Size distribution of contigs obtained from clean reads. (B) Size distribution of unigenes generated by further assembly of contigs.</p

Receiver operating characteristics analysis based on the model of 7 resected lymph nodes in Stage I, Stage II and Stage I and Stage II results with OS as end point.

<p>In this model, the area under the curve (AUC) was 0.537, 0.586 and 0.719, respectively.</p

Species distribution of Blastx matches (with an E-value <10⁻⁵) to the unigenes against nr.

<p>Species distribution is shown as the percentage of total homologous sequences with an E-value of at least 10⁻⁵. We used the first hit of each sequence for analysis. Different colors represent different species.</p

Independent prognostic factor for OS and DFS by multivariate Cox regression analysis for the entire cohort of patients (n = 428).

<p>OS, overall survival; DFS, disease-free survival; HR, hazard ratio; 95% CI, 95% confidence interval; <i>p</i>, <i>p</i>-value; NS, not significant; nLNs, the number of resected lymph nodes;</p>*<p>variables, considering 65 as age cutoff and 3.5cm as cutoff for nLNs.</p

Relative DNA stainig in nuclei of <i>Tribolium castaneum</i> (A) and <i>Dastarcus helophoroides</i> (B).

<p>Relative red fluorescence of PI-stained nuclei shows a ratio of approximate 1.27:1.00 between T. castaneum (2C mean  = 122.0) and D. helophoroides (2C mean  = 96.0). PI staining time  = 4.8 h.</p

Gene Ontology annotation and classification of the <i>Dastarcus helophoroides</i> transcriptome.

<p>The results were summarized in three main categories: biological process, cellular component, and molecular function. The right y-axis indicates the number of genes in the category. The left y-axis indicates the percentage of a specific category of genes in that main category.</p

Patients’ characteristics.

<p>Patients’ characteristics.</p

Resected LNs’ characteristics.

<p>Resected LNs’ characteristics.</p