title: Final steps in juvenile hormone biosynthesis in the desert locust, Schistocerca gregaria.
abstract: Two genes coding for enzymes previously reported to be involved in the final steps of juvenile hormone (JH) biosynthesis in different insect species, were characterised in the desert locust, Schistocerca gregaria. Juvenile hormone acid O-methyltransferase (JHAMT) was previously described to catalyse the conversion of farnesoic acid (FA) and JH acid to their methyl esters, methyl farnesoate (MF) and JH respectively. A second gene, CYP15A1 was reported to encode a cytochrome P450 enzyme responsible for the epoxidation of MF to JH. Additionally, a third gene, FAMeT (originally reported to encode a farnesoic acid methyltransferase) was included in this study. Using q-RT-PCR, all three genes (JHAMT, CYP15A1 and FAMeT) were found to be primarily expressed in the CA of the desert locust, the main biosynthetic tissue of JH. An RNA interference approach was used to verify the orthologous function of these genes in S. gregaria. Knockdown of the three genes in adult animals followed by the radiochemical assay (RCA) for JH biosynthesis and release showed that SgJHAMT and SgCYP15A1 are responsible for synthesis of MF and JH respectively. Our experiments did not show any involvement of SgFAMeT in JH biosynthesis in the desert locust. Effective and selective inhibitors of SgJHAMT and SgCYP15A1 would likely represent selective biorational locust control agents.
authors.affiliation: Department of Molecular Developmental Physiology and Signal Transduction, Animal Physiology and Neurobiology, Zoological Institute, K.U. Leuven, Naamsestraat 59, B-3000 Leuven, Belgium.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Marchal
authors.forename: JinRui
authors.initials: J
authors.lastname: Zhang
authors.forename: Liesbeth
authors.initials: L
authors.lastname: Badisco
authors.forename: Heleen
authors.initials: H
authors.lastname: Verlinden
authors.forename: Ekaterina F
authors.initials: EF
authors.lastname: Hult
authors.forename: Pieter
authors.initials: P
authors.lastname: Van Wielendaele
authors.forename: Koichiro J
authors.initials: KJ
authors.lastname: Yagi
authors.forename: Stephen S
authors.initials: SS
authors.lastname: Tobe
authors.forename: Jozef
authors.initials: J
authors.lastname: Vanden Broeck
mesh_terms: D000818:Animals; D003889:Desert Climate; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D006110:Grasshoppers / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism; D007605:Juvenile Hormones / Q000096:biosynthesis*; D008969:Molecular Sequence Data; D010802:Phylogeny
chemical_list: D005231:Fatty Acids, Unsaturated; D019476:Insect Proteins; D007605:Juvenile Hormones; C007702:farnesoic acid