High-throughput profiling of diapause regulated genes from Trichogramma dendrolimi, an important egg parasitoid

Abstract

Background The parasitoid insect Trichogramma dendrolimi can successfully enter diapause at the prepupal stage. Thus, diapause is an efficient preservation method during the mass production of T. dendrolimi. Previous studies on diapause have focused mostly on ecological characteristics, so the molecular mechanism of diapause in T. dendrolimi is mostly unknown. In this study, we compared transcriptomes of diapause and non-diapause T. dendrolimi to identify genes involved in the development of diapause. Results Transcriptome sequencing was performed using different samples, including diapause prepupae, pupae after diapause, normal prepupae, and pupae. This initially yielded a total of 87,022 unigenes with an average length of 1,604 bp. By removing redundant sequences and those without significant BLAST hits, a non-redundant dataset was generated, containing 7,593 sequences with an average length of 3351 bp. Among the differentially expressed genes, 1,204 were specifically expressed during the diapause stage, and 820 were significantly up-regulated. The result of GO enrichment analysis revealed that binding, oxidation−reduction process, and ribosome biogenesis were significantly affected. Ten genes were selected for validation using a quantitative real-time PCR (qPCR). The changes showed the same trend between the qPCR and RNA-Seq results. Based on previous studies and our data, several genes were identified to be involved in diapause, including UDP-glucuronosyltransferase; Glutathione-S-transferase, ATGs, zinc finger protein genes, cell cycle-related genes, Trehalase, trehalose transporter, hsp68, p53, and DNA damage-regulated gene 1 (pdrg1), and genes related to lipid metabolism were also included. Conclusions In this study, we generated a great amount of transcriptome data from T. dendrolimi, providing a resource for gene function research. The diapause-related genes that we identified establish a valuable basis for future studies on the molecular mechanisms of diapause, not only for T. dendrolimi, but for other species as well.