Ecdysone receptor isoform‐B mediates soluble trehalase expression to regulate growth and development in the mirid bug, Apolygus lucorum (Meyer‐Dür)

Abstract

Ecdysone receptor (EcR) is the hormonal receptor of ecdysteroids and strictly regulates growth and development in insects. However, the action mechanism of EcR is not very clear. In this study, the cDNA of EcR isoform-B was cloned from Apolygus lucorum (AlEcR-B) and its expression profile was investigated. We reduced AlEcR-B mRNA expression using systemic RNA interference in vivo, and obtained knockdown specimens. Examination of these specimens indicated that AlEcR-B is required for nymphal survival, and that reduced expression is associated with longer development time and lower nymphal weight. To investigate the underlying molecular mechanism of the observed suppression effects, we selected trehalase for a detailed study. Transcript encoding soluble trehalase (AlTre-1) was up-regulated by 20-hydroxyecdysone and in agreement with the mRNA expression of AlEcR-B. The expression profile of AlTre-1, soluble trehalase activity and translated protein level in the midgut of surviving nymphs were down-regulated, compared with controls, after the knockdown expression of AlEcR-B. By contrast, membrane-bound trehalase activity, the related gene expression and translated protein level remained at their initial levels. However, trehalose content significantly increased and the glucose content significantly decreased under the same conditions. We propose that AlEcR-B controls normal carbohydrate metabolism by mediating the expression of AlTre-1 to regulate the growth and development in A. lucorum, which provide an extended information into the functions of AlEcR-B.

The Modulation of Trehalose Metabolism by 20-Hydroxyecdysone in Antheraea pernyi (Lepidoptera: Saturniidae) During its Diapause Termination and Post-Termination Period

“…Thus, under these circumstances, trehalose cannot be converted into glucose to provide energy and substrate for chitin synthesis for pupal-adult development, which could be the reason of the delay in adult emergence that was observed in CucB- treated A. pernyi . This observation is in agreement with a previous study, in which the knockdown of EcR was found to reduce the soluble trehalase activity, in turn preventing the normal growth and development of A. lucorum ( Tan et al 2015 ).…”

“…Consistent with our results, the expression levels of LdTre-1a , LdTre-1b , and LdTre-2 were significantly reduced after LdEcR gene in Leptinotarsa decemlineata (Coleoptera: Chrysomelidae) third-instar larvae was knocked down ( Shi et al 2016 ). Also, mRNA and protein levels of AlTre1 decreased after the injection of AlEcRB -specific siRNA, which resulted in decreased soluble trehalase activity and increased trehalose content in the nymphs of A. lucorum ( Tan et al 2015 ). In the present study, neither the treatment with ApEcRB1 -specific RNAi nor with CucB led to the decrease in ApTre-1B expression ( Figs.…”

Functional characterization of three trehalase genes regulating the chitin metabolism pathway in rice brown planthopper using RNA interference

“…Other studies showed that the mRNA levels of TRE1 increase before insect moulting and after the injection of 20E 21 23 24 . In Apolygus lucorum , ecdsone receptor (EcR) isoform-B mediates the expression of TRE1 expression and regulates growth and development 25 .…”

Ecdysone receptor isoforms play distinct roles in larval–pupal–adult transition in Leptinotarsa decemlineata

“…EcRB mutants having removed both EcRB1 and EcRB2 show defects in larval molting, arresting at the boundaries between the three larval stages (Schubiger et al ., ). Similarly, silencing either EcRA or EcRB1 inhibits growth and increases juvenile mortalities in A. lucorum (Tan et al ., , b).…”