Transcriptome Sequencing Reveals Potential Mechanisms of the Maternal Effect on Egg Diapause Induction of Locusta migratoria

Abstract

Photoperiod is one of the most important maternal factors with an impact on the offspring diapause induction of Locusta migratoria. Previous studies have shown that forkhead box protein O (FOXO) plays an important role in regulating insect diapause, but how photoperiod stimulates maternal migratory locusts to regulate the next generation of egg diapause through the FOXO signaling pathway still needs to be addressed. In this study, the transcriptomes of ovaries and fat bodies of adult locusts under a long and short photoperiod were obtained. Among the total of 137 differentially expressed genes (DEGs) in both ovaries and fat bodies, 71 DEGs involved in FOXO signaling pathways might be closely related to diapause induction. 24 key DEGs were selected and their expression profiles were confirmed to be consistent with the transcriptome results using qRT-PCR. RNA interference was then performed to verify the function of retinoic acid induced protein gene (rai1) and foxo. Egg diapause rates were significantly increased by RNAi maternal locusts rai1 gene under short photoperiods. However, the egg diapause rates were significantly decreased by knock down of the foxo gene in the maternal locusts under a short photoperiod. In addition, reactive oxygen species (ROS) and superoxide dismutase (SOD) activities were promoted by RNAi rai1. We identified the candidate genes related to the FOXO pathway, and verified the diapause regulation function of rai1 and foxo under a short photoperiod only. In the future, the researchers can work in the area to explore other factors and genes that can promote diapause induction under a long photoperiod.

Molecular identification and diapause‐related functional characterization of a novel dual‐specificity kinase gene, MPKL, in Locusta migratoria

“…MPKL enhanced ROS activity, whereas it inhibited POD activities in both fat bodies and ovaries under long and short days. These results were consistent with those of a previous study [6].…”

“…The candidate dual‐specificity kinases genes, differentially expressed between long and short day treated L. migratoria , have been reported previously . In the present study, we initially aligned the dual‐specificity kinase MPKL gene to the L. migratoria genome.…”

“…A previous study on transcriptome of L. migratoria showed that the dual‐specificity protein kinase MPKL gene was differentially expressed in both L_OVA versus S_OVA and L_FAT versus S_FAT groups . FPKM (i.e.…”

“…In the mouse, a high level of ROS was needed to keep FOXO active [34]. The results of previous studies also suggested that the ROS level and FOXO activity increased, whereas peroxidase expression decreased, when diapause induction of L. migratoria occurred under short day conditions [6]. Furthermore, contrasting reports are available with respect to both activation and inhibition of the PI3K/ Akt and MAPK pathway via FOXO [24,25].…”

Serpin7 controls egg diapause of migratory locust (Locusta migratoria) by regulating polyphenol oxidase

“…The photoperiodic regimen used for nondiapause locusts in the experiment was 16 h light : 8 h darkness. Similarly, to induce diapause, we reared locusts under a short photoperiod at 10 h light : 14 h darkness, 27 °C and 60% relative humidity [23,24]. Freshly grown wheat seedlings were fed to the locusts in the laboratory.…”