Roles of a putative DopEcR-like gene in temperature stress response and development of the oriental fruit fly, Bactrocera dorsalis.

The Drosophila melanogaster gene CG18314 encodes a DopEcR, which is implicated in various physiological functions. However, genome-wide analyses of insect neurohormone GPCRs have identified CG13579 and its orthologs as putative DopEcRs, whose functions remain largely unexplored. We here identified an ortholog of CG13579 in the oriental fruit fly, Bactrocera dorsalis. Phylogenetic analysis classified these genes as dopamine/ecdysteroid receptors (DopEcR). RT-qPCR analysis revealed that expression of the BdorDopEcR-like gene significantly increased under thermal stress. We successfully generated a BdorDopEcR-like knockout strain from the wild-type (WT) background using the CRISPR/Cas9 system. Compared with WT flies, the Bdor-DopEcR-like-/- mutants exhibited shorter heat knockdown time and prolonged chill coma recovery times. Upon exposure to extreme heat, seizure-like behaviors were significantly more frequent in mutants than in WT individuals. Moreover, the survival rate of Bdor-DopEcR-like-/- flies under extreme high temperatures was markedly reduced compared with that of WT flies. Additionally, knockout of Bdor-DopEcR-like led to decreased rates of egg hatching, pupation, and adult eclosion. These findings provide valuable insights into the physiological functions of DopEcR-like receptors in insect thermal stress tolerance and developmental processes.