title: Knockdown of NADPH-cytochrome P450 reductase results in reduced resistance to buprofezin in the small brown planthopper, Laodelphax striatellus (fallén).
abstract: NADPH-cytochrome P450 reductase (CPR) plays an important role in cytochrome P450 function, and CPR knockdown in several insects leads to increased susceptibility to insecticides. However, a putative CPR gene has not yet been fully characterized in the small brown planthopper Laodelphax striatellus, a notorious agricultural pest in rice that causes serious damage by transmitting rice stripe and rice black-streaked dwarf viruses. The objective of this study was to clone the cDNA and to knock down the expression of the gene that encodes L. striatellus CPR (LsCPR) to further determine whether P450s are involved in the resistance of L. striatellus to buprofezin. First, the full-length cDNA of LsCPR was cloned and found to contain an open reading frame (ORF) encoding a polypeptide of 679 amino acids with a calculated molecular mass and isoelectric point of 76.92kDa and 5.37, respectively. The deduced amino acid sequence shares high identity with the CPRs of other insects (98%, 97%, 75% and 68% for Sogatella furcifera, Nilaparvata lugens, Cimex lectularius and Anopheles gambiae, respectively) and possesses the characteristic features of classical CPRs, such as an N-terminal membrane anchor and conserved domains for flavin mononucleotide (FMN), flavin adenine dinucleotide (FAD) and nicotinamide adenine dinucleotide phosphate (NADPH) binding. Phylogenetic analysis revealed that LsCPR is located in a branch along with the CPRs of other hemipteran insects. LsCPR mRNA was detectable in all examined body parts and developmental stages of L. striatellus, as determined by real-time quantitative PCR (qPCR), and transcripts were most abundant in the adult abdomen and in first-instar nymphs and adults. Ingestion of 200μg/mL of LsCPR double-stranded RNA (dsLsCPR) by the planthopper for 5days significantly reduced the transcription level of LsCPR. Moreover, silencing of LsCPR caused increased susceptibility to buprofezin in a buprofezin-resistant (YN-BPF) strain but not in a susceptible (YN) strain. These data further suggested that the P450-mediated metabolic detoxification of xenobiotics might be an important mechanism for buprofezin resistance in L. striatellus.
authors.affiliation: Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China.
authors.forename: Yueliang
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China; Key Laboratory of Monitoring and Management of Plant Disease and Insects, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, China.
authors.forename: Yaming
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China.
authors.forename: Lihua
authors.initials: L
authors.lastname: Wang
authors.affiliation: Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Yao
authors.affiliation: Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China.
authors.forename: Huifang
authors.initials: H
authors.lastname: Guo
authors.affiliation: Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China.
authors.forename: Jichao
authors.initials: J
authors.lastname: Fang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D006430:Hemiptera / Q000187:drug effects*; D007305:Insecticide Resistance / Q000235:genetics*; D008969:Molecular Sequence Data; D009251:NADPH-Ferrihemoprotein Reductase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D017386:Sequence Homology, Amino Acid; D013829:Thiadiazines / Q000494:pharmacology*
chemical_list: D013829:Thiadiazines; C083997:buprofezin; D009251:NADPH-Ferrihemoprotein Reductase
keywords: Buprofezin; Laodelphax striatellus; NADPH-cytochrome P450 reductase; RNA interference