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Nuclear receptor ecdysone-induced protein 75 is required for larval-pupal metamorphosis in the Colorado potato beetle Leptinotarsa decemlineata (Say).
Guo, W-C; Liu, X-P; Fu, K-Y; Shi, J-F; Lü, F-G; Li, G-Q.
Affiliation
  • Guo WC; Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing, China.
  • Liu XP; Department of Plant Protection, Xinjiang Academy of Agricultural Sciences, Urumqi, China.
  • Fu KY; Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing, China.
  • Shi JF; Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing, China.
  • Lü FG; Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing, China.
  • Li GQ; Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing, China.
Insect Mol Biol ; 25(1): 44-57, 2016 Feb.
Article in En | MEDLINE | ID: mdl-26542892
ABSTRACT
20-hydroxyecdysone (20E) and juvenile hormone (JH) are key regulators of insect development. In this study, three Leptinotarsa decemlineata Ecdysone-induced protein 75 (LdE75) cDNAs (LdE75A, B and C) were cloned from L. decemlineata. The three LdE75 isoforms were highly expressed just before or right after each moult. Within the fourth larval instar, they showed a small rise and a big peak 40 and 80 h after ecdysis. The expression peaks of the three LdE75s coincided with the peaks of circulating 20E levels. In vitro midgut culture and in vivo bioassay revealed that 20E and an ecdysteroid agonist halofenozide (Hal) enhanced LdE75 expression in the day 1 final larval instars. Conversely, a decrease in 20E by feeding a double-stranded RNA (dsRNA) against an ecdysteroidogenesis gene, Shade (LdSHD), repressed the expression of LdE75. Moreover, Hal upregulated the expression of the three LdE75s in LdSHD-silenced larvae. Thus, 20E pulses activate the transcription of LdE75s. Furthermore, ingesting dsE75-1 and dsE75-2 from a common fragment of the three isoforms successfully knocked down these LdE75s, and caused developmental arrest. Finally, knocking down LdE75s significantly repressed the transcription of three ecdysteroidogenesis genes, lowered the 20E titre and affected the expression of two 20E-response genes. Silencing LdE75s also induced the expression of a JH biosynthesis gene, increased JH titre and activated the transcription of a JH early-inducible gene. Thus, Ld E75s are required for larval-pupal metamorphosis and act mainly by modulating 20E and JH titres and mediating their signalling pathways.
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Full text: 1 Collection: 01-internacional Database: MEDLINE Main subject: Coleoptera / Receptors, Cytoplasmic and Nuclear / Insect Proteins / Metamorphosis, Biological Limits: Animals Language: En Journal: Insect Mol Biol Journal subject: BIOLOGIA MOLECULAR Year: 2016 Document type: Article Affiliation country:

Full text: 1 Collection: 01-internacional Database: MEDLINE Main subject: Coleoptera / Receptors, Cytoplasmic and Nuclear / Insect Proteins / Metamorphosis, Biological Limits: Animals Language: En Journal: Insect Mol Biol Journal subject: BIOLOGIA MOLECULAR Year: 2016 Document type: Article Affiliation country: