title: RNA interference suppression of the receptor tyrosine kinase Torso gene impaired pupation and adult emergence in Leptinotarsa decemlineata.
abstract: In Drosophila melanogaster prothoracic gland (PG) cells, Torso mediates prothoracicotropic hormone (PTTH)-triggered mitogen activated protein kinase (MAPK) pathway (consisting of four core components Ras, Raf, MEK and ERK) to stimulate ecdysteroidogenesis. In this study, LdTorso, LdRas, LdRaf and LdERK were cloned in Leptinotarsa decemlineata. The four genes were highly or moderately expressed in the larval prothoracic glands. At the first- to third-instar stages, their expression levels were higher just before and right after the molt, and were lower in the mid instars. At the fourth-instar stage, their transcript levels were higher before prepupal stage. RNA interference-mediated knockdown of LdTorso delayed larval development, increased pupal weight, and impaired pupation and adult emergence. Moreover, knockdown of LdTorso decreased the mRNA levels of LdRas, LdRaf and LdERK, repressed the transcription of two ecdysteroidogenesis genes (LdPHM and LdDIB), lowered 20E titer, and downregulated the expression of several 20E-response genes (LdEcR, LdUSP, LdHR3 and LdFTZ-F1). Furthermore, silencing of LdTorso induced the expression of a JH biosynthesis gene LdJHAMT, increased JH titer, and activated the transcription of a JH early-inducible gene LdKr-h1. Thus, our results suggest that Torso transduces PTTH-triggered MAPK signal to regulate ecdysteroidogenesis in the PGs in a non-drosophiline insect.
authors.affiliation: Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China. Electronic address: 475652324@qq.com.
authors.forename: Tao-Tao
authors.initials: TT
authors.lastname: Zhu
authors.affiliation: Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China. Electronic address: mqw102082@163.com.
authors.forename: Qing-Wei
authors.initials: QW
authors.lastname: Meng
authors.affiliation: Department of Plant Protection, Xinjiang Academy of Agricultural Sciences, Urumqi 830091, China. Electronic address: gwc1966@163.com.
authors.forename: Wen-Chao
authors.initials: WC
authors.lastname: Guo
authors.affiliation: Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China. Electronic address: ligq@njau.edu.cn.
authors.forename: Guo-Qing
authors.initials: GQ
authors.lastname: Li
mesh_terms: D000818:Animals; D001517:Coleoptera / Q000201:enzymology / Q000235:genetics / Q000254:growth & development*; D004441:Ecdysterone / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D007301:Insect Hormones / Q000378:metabolism; D007605:Juvenile Hormones / Q000378:metabolism; D007814:Larva / Q000235:genetics / Q000254:growth & development; D008675:Metamorphosis, Biological; D034622:RNA Interference; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics* / Q000378:metabolism
chemical_list: D007301:Insect Hormones; D007605:Juvenile Hormones; D004441:Ecdysterone; C009089:prothoracicotropic hormone; D020794:Receptor Protein-Tyrosine Kinases
keywords: 20-Hydroxyecdysone; Juvenile hormone; Leptinotarsa decemlineata; Metamorphosis; Torso