title: Molecular cloning and RNA interference-mediated functional characterization of a Halloween gene spook in the white-backed planthopper Sogatella furcifera.
abstract: BACKGROUND
  Ecdysteroid hormones ecdysone and 20-hydroxyecdysone play fundamental roles in insect postembryonic development and reproduction. Five cytochrome P450 monooxygenases (CYPs), encoded by Halloween genes, have been documented to be involved in the ecdysteroidogenesis in insect species of diverse orders such as Diptera, Lepidoptera and Orthoptera. Up to now, however, the involvement of the Halloween genes in ecdysteroid synthesis has not been confirmed in hemipteran insect species.
  
  
  RESULTS
  In the present paper, a Halloween gene spook (Sfspo, Sfcyp307a1) was cloned in the hemipteran Sogatella furcifera. SfSPO has three insect conserved P450 motifs, i.e., Helix-K, PERF and heme-binding motifs. Temporal and spatial expression patterns of Sfspo were evaluated by qPCR. Sfspo showed three expression peaks in late second-, third- and fourth-instar stages. In contrast, the expression levels were lower and formed three troughs in the newly-molted second-, third- and fourth-instar nymphs. On day 3 of the fourth-instar nymphs, Sfspo clearly had a high transcript level in the thorax where PGs were located. Dietary introduction of double-stranded RNA (dsRNA) of Sfspo into the second instars successfully knocked down the target gene, and greatly reduced expression level of ecdysone receptor (EcR) gene. Moreover, knockdown of Sfspo caused lethality and delayed development during nymphal stages. Furthermore, application of 20-hydroxyecdysone on Sfspo-dsRNA-exposed nymphs did not increase Sfspo expression, but could almost completely rescue SfEcR expression, and relieved the negative effects on nymphal survival and development.
  
  
  CONCLUSIONS
  In S. furcifera, Sfspo was cloned and the conservation of SfSPO is valid. Thus, SfSPO is probably also involved in ecdysteroidogenesis for hemiptera.
authors.affiliation: Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China. liguoqing001234@yahoo.com.cn.
authors.forename: Shuang
authors.initials: S
authors.lastname: Jia
authors.forename: Pin-Jun
authors.initials: PJ
authors.lastname: Wan
authors.forename: Li-Tao
authors.initials: LT
authors.lastname: Zhou
authors.forename: Li-Li
authors.initials: LL
authors.lastname: Mu
authors.forename: Guo-Qing
authors.initials: GQ
authors.lastname: Li
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular / Q000379:methods; D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D055785:Gene Knockdown Techniques; D017344:Genes, Insect; D005804:Genes, Lethal; D006430:Hemiptera / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D060888:Real-Time Polymerase Chain Reaction; D011987:Receptors, Steroid / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D019476:Insect Proteins; D011987:Receptors, Steroid; C055469:ecdysone receptor; D003577:Cytochrome P-450 Enzyme System