AUTHOR=Shi Yan , Jiang Hong-Bo , Gui Shun-Hua , Liu Xiao-Qiang , Pei Yu-Xia , Xu Li , Smagghe Guy , Wang Jin-Jun 

TITLE=Ecdysis Triggering Hormone Signaling (ETH/ETHR-A) Is Required for the Larva-Larva Ecdysis in Bactrocera dorsalis (Diptera: Tephritidae)

JOURNAL=Frontiers in Physiology

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2017.00587

DOI=10.3389/fphys.2017.00587

ISSN=1664-042X

ABSTRACT=<p>Insects must undergo ecdysis for successful development and growth, and the ecdysis triggering hormone (ETH), released by the Inka cells, is a master hormone in this process. In this study, we determined the sequence of the ETH precursor and receptors in an agriculturally important pest insect, the oriental fruit fly <italic>Bactrocera dorsalis</italic> (Hendel). We identified two functionally distinct splice receptor isoforms: BdETH-R-A and BdETH-R-B, and when expressed in Chinese hamster ovary (CHO-WTA11) cells, they exhibited a high sensitivity to the two mature peptides BdETH1 and BdETH2. The <italic>BdETH</italic> transcript was detected in the tracheal tissue of the larvae. Inka cells were identified with immunohistochemical antibody staining against <italic>Drosophila melanogaster</italic> ETH1, and <italic>in situ</italic> hybridization with specific DNA probes. Selective RNA silencing of <italic>BdETH</italic> or <italic>BdETH-R-A</italic>, but not of <italic>BdETH-R-B</italic>, caused developmental failure at ecdysis. The dsRNA-treated larvae displayed tracheal defects and could not shed the old cuticle followed by death. Our results demonstrated that BdETH, via activation of BdETH-R-A but not ETH-R-B, plays an essential role in regulating the process of larva-larva ecdysis in <italic>B. dorsalis</italic>.</p>