title: Identification and biochemical characterization of Laodelphax striatellus neutral ceramidase.
abstract: Ceramidases are a group of enzymes that catalyse hydrolysis of ceramides to generate fatty acid and sphingosine. In this study, we report the cloning and characterization of the rice small brown planthopper Laodelphax striatellus neutral ceramidase (nCDase), LsnCer. LsnCer was identified by sequencing the transcriptome of L. striatellus and is a protein of 717 amino acids with a predicted molecular weight of 79.3 kDa. Similarly to other known nCDases, the optimum pH for LsnCer is 8.0 and the optimum temperature is 37 °C for its in vitro activity. LsnCer activity is inhibited by Zn(2+) significantly and Fe(2+) slightly. LsnCer has broad substrate specificity with a preference for ceramides with a medium acyl-chain or a monounsaturated long acyl-chain. Infection with rice strip virus (RSV) or treatment with insecticides significantly increased LsnCer mRNA expression and its enzymatic activity in L. striatellus. These results suggest that LsnCer is a bona fide nCDase that may have a role in adaption of L. striatellus to environmental stresses.
authors.affiliation: State Key Laboratory of Rice Biology, Key laboratory of Agricultural Entomology, the Ministry of Agriculture of China, Hangzhou, Zhejiang, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Zhou
authors.forename: X-W
authors.initials: XW
authors.lastname: Lin
authors.forename: Y-R
authors.initials: YR
authors.lastname: Zhang
authors.forename: Y-J
authors.initials: YJ
authors.lastname: Huang
authors.forename: C-H
authors.initials: CH
authors.lastname: Zhang
authors.forename: Q
authors.initials: Q
authors.lastname: Yang
authors.forename: H-Y
authors.initials: HY
authors.lastname: Li
authors.forename: J-Q
authors.initials: JQ
authors.lastname: Yuan
authors.forename: J-A
authors.initials: JA
authors.lastname: Cheng
authors.forename: R
authors.initials: R
authors.lastname: Xu
authors.forename: C
authors.initials: C
authors.lastname: Mao
authors.forename: Z-R
authors.initials: ZR
authors.lastname: Zhu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D055572:Ceramidases / Q000235:genetics / Q000378:metabolism*; D005260:Female; D006430:Hemiptera / Q000201:enzymology* / Q000235:genetics / Q000821:virology; D054884:Host-Pathogen Interactions; D007306:Insecticides; D008297:Male; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA; D013312:Stress, Physiological; D029364:Tenuivirus / Q000502:physiology*
chemical_list: D007306:Insecticides; D055572:Ceramidases
keywords: LsnCer; activity; insecticide; mRNA; nCDase; rice strip virus