title: Two Leptinotarsa uridine diphosphate N-acetylglucosamine pyrophosphorylases are specialized for chitin synthesis in larval epidermal cuticle and midgut peritrophic matrix.
abstract: Uridine diphosphate-N-acetylglucosamine-pyrophosphorylase (UAP) is involved in the biosynthesis of chitin, an essential component of the epidermal cuticle and midgut peritrophic matrix (PM) in insects. In the present paper, two putative LdUAP genes were cloned in Leptinotarsa decemlineata. In vivo bioassay revealed that 20-hydroxyecdysone (20E) and an ecdysteroid agonist halofenozide activated the expression of the two LdUAPs, whereas a decrease in 20E by RNA interference (RNAi) of an ecdysteroidogenesis gene LdSHD and a 20E signaling gene LdFTZ-F1 repressed the expression. Juvenile hormone (JH), a JH analog pyriproxyfen and an increase in JH by RNAi of an allatostatin gene LdAS-C downregulated LdUAP1 but upregulated LdUAP2, whereas a decrease in JH by silencing of a JH biosynthesis gene LdJHAMT had converse effects. Thus, expression of LdUAPs responded to both 20E and JH. Moreover, knockdown of LdUAP1 reduced chitin contents in whole larvae and integument samples, thinned tracheal taenidia, impaired larval-larval molt, larval-pupal ecdysis and adult emergence. In contrast, silencing of LdUAP2 significantly reduced foliage consumption, decreased chitin content in midgut samples, damaged PM, and retarded larval growth. The resulting larvae had lighter fresh weights, smaller body sizes and depleted fat body. As a result, the development was arrested. Combined knockdown of LdUAP1 and LdUAP2 caused an additive negative effect. Our data suggest that LdUAP1 and LdUAP2 have specialized functions in biosynthesizing chitin in the epidermal cuticle and PM respectively 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 210095, China. Electronic address: shijf1214@126.com.
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 210095, China. Electronic address: fujia878@163.com.
authors.forename: Jia
authors.initials: J
authors.lastname: Fu
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: mll700819@njau.edu.cn.
authors.forename: Li-Li
authors.initials: LL
authors.lastname: Mu
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; D002686:Chitin / Q000096:biosynthesis*; D003001:Cloning, Molecular; D001517:Coleoptera / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D004064:Digestive System / Q000378:metabolism; D004441:Ecdysterone / Q000378:metabolism; D017344:Genes, Insect; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism*; D007605:Juvenile Hormones / Q000378:metabolism; D007814:Larva / Q000378:metabolism; D018978:Molting / Q000235:genetics; D014537:Uridine Diphosphate N-Acetylglucosamine / Q000235:genetics / Q000378:metabolism*
chemical_list: D019476:Insect Proteins; D007605:Juvenile Hormones; D002686:Chitin; D014537:Uridine Diphosphate N-Acetylglucosamine; D004441:Ecdysterone
keywords: Chitin; Ecdysis; Hormone; Uridine diphosphate-N-acetylglucosamine-pyrophosphorylase