title: IDENTIFICATION AND HORMONE INDUCTION OF PUTATIVE CHITIN SYNTHASE GENES AND SPLICE VARIANTS IN Leptinotarsa decemlineata (SAY).
abstract: Chitin synthase (ChS) plays a critical role in chitin synthesis and excretion. In this study, two ChS genes (LdChSA and LdChSB) were identified in Leptinotarsa decemlineata. LdChSA contains two splicing variants, LdChSAa and LdChSAb. Within the first, second, and third larval instars, the mRNA levels of LdChSAa, LdChSAb, and LdChSB coincide with the peaks of circulating 20-hydroxyecdysone (20E) and juvenile hormone (JH). In vitro culture of midguts and an in vivo bioassay revealed that 20E and an ecdysteroid agonist halofenozide stimulated the expression of the three LdChSs. Conversely, a reduction of 20E by RNA interference (RNAi) of an ecdysteroidogenesis gene LdSHD repressed the expression of these LdChSs, and ingestion of halofenozide by LdSHD RNAi larvae rescued the repression. Moreover, disruption of 20E signaling by RNAi of LdEcR, LdE75, LdHR3, and LdFTZ-F1 reduced the expression levels of these genes. Similarly, in vitro culture and an in vivo bioassay showed that exogenous JH and a JH analog methoprene activated the expression of the three LdChSs, whereas a decrease in JH by RNAi of a JH biosynthesis gene LdJHAMT downregulated these LdChSs. It seems that JH upregulates LdChSs at the early stage of each instar, whereas a 20E pulse triggers the transcription of LdChSs during molting in L. decemlineata.
authors.affiliation: Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing, China.
authors.forename: Ji-Feng
authors.initials: JF
authors.lastname: Shi
authors.affiliation: Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing, China.
authors.forename: Li-Li
authors.initials: LL
authors.lastname: Mu
authors.affiliation: Department of Plant Protection, Xinjiang Academy of Agricultural Sciences, Urumqi, China.
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, China.
authors.forename: Guo-Qing
authors.initials: GQ
authors.lastname: Li
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002687:Chitin Synthase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D001517:Coleoptera / Q000145:classification / Q000201:enzymology* / Q000235:genetics* / Q000254:growth & development; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D004441:Ecdysterone / Q000378:metabolism; D005786:Gene Expression Regulation; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D007527:Isoenzymes / Q000235:genetics; D007605:Juvenile Hormones / Q000378:metabolism; D007814:Larva / Q000201:enzymology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D016415:Sequence Alignment
chemical_list: D018076:DNA, Complementary; D019476:Insect Proteins; D007527:Isoenzymes; D007605:Juvenile Hormones; D012333:RNA, Messenger; D004441:Ecdysterone; D002687:Chitin Synthase
keywords: 20-hydroxyecdysone; Leptinotarsa decemlineata; chitin synthase; juvenile hormone