Ecdysone receptor isoforms play distinct roles in larval–pupal–adult transition in Leptinotarsa decemlineata. (12th March 2019)

• Record Type: Journal Article
• Authors: Xu, Qing‐Yu; Deng, Pan; Zhang, Qiong; Li, Ang; Fu, Kai‐Yun; Guo, Wen‐Chao; Li, Guo‐Qing
• Is Part Of: Insect science. Volume 27:Number 3(2020)
• Page Start: 487
• Page End: 499
• Publication Date: 2019-03-12
• Subjects: ecdysone receptor -- Leptinotarsa decemlineata -- metamorphosis -- RNA interference; Insects -- Periodicals; Entomology -- Periodicals; 595.705
• DOI: 10.1111/1744-7917.12662
• Languages: English
• ISSNs: 1672-9609

Abstract

Abstract: A heterodimer of two nuclear receptors, ecdysone receptor (EcR) and ultraspiracle, mediates 20‐hydroxyecdysone (20E) signaling to modulate many aspects in insect life, such as molting and metamorphosis, reproduction, diapause and innate immunity. In the present paper, we intended to determine the isoform‐specific roles of EcR during larval–pupal–adult transition in the Colorado potato beetle. Double‐stranded RNAs (dsRNAs) were prepared using the common (ds EcR ) or isoform‐specific (ds EcRA, ds EcRB1 ) regions of EcR as templates. Ingestion of either ds EcR or ds EcRA, rather than ds EcRB1, by the penultimate (3rd) and final (4th) instar larvae caused failure of larval–pupal and pupal–adult ecdysis. The RNA interference (RNAi) larvae remained as prepupae, or became deformed pupae and adults. Determination of messenger RNA (mRNA) levels of EcR isoforms found that LdEcRA regulates the expression of LdEcRB1 . Moreover, silencing the two EcR transcripts, LdEcRA or LdEcRB1 reduced the mRNA levels of Ldspo and Ldsad, and lowered 20E titer. In contrast, the expression levels of HR3, HR4, E74 and E75 were significantly decreased in the LdEcR or LdEcRA RNAi larvae, but not in LdEcRB1 depleted specimens. Dietary supplement with 20E did not restore the expression of five 20E signaling genes ( USP, HR3, HR4, E74 and E75 ), and only partially alleviated the pupation defects in ds EcR‐ or ds EcRA ‐fed beetles. These data suggest that EcR plays isoform‐specific roles in the regulation of ecdysteroidogenesis and the transduction of 20E signal in L. decemlineata .