RNA-seq analysis of gene expression changes during pupariation in Bactrocera dorsalis (Hendel) (Diptera: Tephritidae)

Abstract

BackgroundThe oriental fruit fly, Bactrocera dorsalis (Hendel) has been considered to be one of the most important agricultural pest around the world. As a holometabolous insect, larvae must go through a metamorphosis process with dramatic morphological and structural changes to complete their development. To better understand the molecular mechanisms of these changes, RNA-seq of B. dorsalis from wandering stage (WS), late wandering stage (LWS) and white puparium stage (WPS) were performed.ResultsIn total, 11,721 transcripts were obtained, out of which 1914 genes (578 up-regulated and 1336 down-regulated) and 2047 genes (655 up-regulated and 1392 down-regulated) were found to be differentially expressed between WS and LWS, as well as between WS and WPS, respectively. Of these DEGs, 1862 and 1996 genes were successfully annotated in various databases. The analysis of RNA-seq data together with qRT-PCR validation indicated that during this transition, the genes in the oxidative phosphorylation pathway, and genes encoding P450s, serine protease inhibitor, and cuticular proteins were down-regulated, while the serine protease genes were up-regulated. Moreover, we found some 20-hydroxyecdysone (20E) biosynthesis and signaling pathway genes had a higher expression in the WS, while the genes responsible for juvenile hormone (JH) synthesis, degradation, signaling and transporter pathways were down-regulated, suggesting these genes might be involved in the process of larval pupariation in B. dorsalis. For the chitinolytic enzymes, the genes encoding chitinases (chitinase 2, chitinase 5, chitinase 8, and chitinase 10) and chitin deacetylase might play the crucial role in the degradation of insect chitin with their expressions significantly increased during the transition. Here, we also found that chitin synthase 1A might be involved in the chitin synthesis of cuticles during the metamorphosis in B. dorsalis.ConclusionsSignificant changes at transcriptional level were identified during the larval pupariation of B. dorsalis. Importantly, we also obtained a vast quantity of RNA-seq data and identified metamorphosis associated genes, which would all help us to better understand the molecular mechanism of metamorphosis process in B. dorsalis.Electronic supplementary materialThe online version of this article (10.1186/s12864-018-5077-z) contains supplementary material, which is available to authorized users.

Potential targets for controlling Bactrocera dorsalis using cuticle‐ and hormone‐related genes revealed by a developmental transcriptome analysis

“…With the rapid development of sequencing technology, high‐throughput sequencing techniques have been used widely in functional investigations of genes related to insect growth and development. In recent years, developmental transcriptomes have been reported in several insect species, including Cyrtotrachelus buqueti , Chrysomya megacephala , Trichopria drosophilae , Dendrolimus punctatus , Bombyx mori , Phenacoccus solenopsis and B. dorsalis …”

“…As a holometabolous insect, B. dorsalis undergoes hatching, two moltings during the larval stages, pupariation and emergence during its life cycle. The previously reported developmental transcriptome data were generated by sequencing samples from four developmental stages or samples from the wandering to white puparium stages . To investigate functional genes in all five metamorphosis‐related stages comprehensively, a more precise and detailed sample collection scheme was adopted.…”

Genome-wide gene expression profiling of the melon fly, Zeugodacus cucurbitae, during thirteen life stages

“…Comprehensive studies of gene expression during various developmental stages in many important insect pests, e.g. the oriental fruit fly Bactrocera dorsalis 13,14 and the ladybird Henosepilachna vigintioctopunctata 6 , have been performed to explore the molecular mechanisms underlying metamorphic development. In C. capitata, the gene expression at the specific embryogenesis stage was also obtained by transcriptomic sequencing technology 15 .…”

“…Gene expression during the specific time strictly in the process of the molting from old larva to the early pupa was also critical to successful molting, e.g. the wondering stage 14 . Although four transcriptomes were released, they are not a good resource because of the lack of biological replicates.…”

“…In addition, the comparative analysis of gene expression with other tephritidae fruit flies can also be performed, e.g. B. dorsalis, C. capitata, in which such data are available 14,30 . Our work represents a valuable resource, and will be helpful for future studies of functional genes associated with metamorphic development and reproduction.…”