title: Multiple cis-acting elements involved in up-regulation of a cytochrome P450 gene conferring resistance to deltamethrin in smal brown planthopper, Laodelphax striatellus (Fallén).
abstract: As well as arising from single point mutations in binding sites or detoxifying enzymes, it is likely that insecticide resistance mechanisms are frequently controlled by multiple genetic factors, resulting in resistance being inherited as a quantitative trait. However, empirical evidence for this is still rare. Here we analyse the causes of up-regulation of CYP6FU1, a monoxygenase implicated in resistance to deltamethrin in the rice pest Laodelphax striatellus. The 5'-flanking region of this gene was cloned and sequenced from individuals of a susceptible and a resistant strain. A luminescent reporter assay was used to evaluate different 5'-flanking regions and their fragments for promoter activity. Mutations enhancing promoter activity in various fragments were characterized, singly and in combination, by site mutation recovery. Nucleotide diversity in flanking sequences was greatly reduced in deltamethrin-resistant insects compared to susceptible ones. Phylogenetic sequence analysis found that CYP6FU1 had five different types of 5'-flanking region. All five types were present in a susceptible strain but only a single type showing the highest promoter activity was present in a resistant strain. Four cis-acting elements were identified whose influence on up-regulation was much more pronounced in combination than when present singly. Of these, two were new transcription factor (TF) binding sites produced by mutations, another one was also a new TF binding site alternated from an existing one, and the fourth was a unique transcription start site. These results demonstrate that multiple cis-acting elements are involved in up-regulating CYP6FU1 to generate a resistance phenotype.
authors: Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Jiangsu, The Key Laboratory of Monitoring and Management of Plant Diseases and Insects, Ministry of Agriculture, Nanjing, 210095, Jiangsu, China.
authors: Jian
authors: J
authors: Pu
authors: Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Jiangsu, The Key Laboratory of Monitoring and Management of Plant Diseases and Insects, Ministry of Agriculture, Nanjing, 210095, Jiangsu, China.
authors: Haina
authors: H
authors: Sun
authors: Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Jiangsu, The Key Laboratory of Monitoring and Management of Plant Diseases and Insects, Ministry of Agriculture, Nanjing, 210095, Jiangsu, China.
authors: Jinda
authors: J
authors: Wang
authors: Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Jiangsu, The Key Laboratory of Monitoring and Management of Plant Diseases and Insects, Ministry of Agriculture, Nanjing, 210095, Jiangsu, China.
authors: Min
authors: M
authors: Wu
authors: Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Jiangsu, The Key Laboratory of Monitoring and Management of Plant Diseases and Insects, Ministry of Agriculture, Nanjing, 210095, Jiangsu, China.
authors: Kangxu
authors: K
authors: Wang
authors: Biological and Environmental Sciences Department, University of Hertfordshire, Hatfield, Hertfordshire, United Kingdom.
authors: Ian
authors: I
authors: Denholm
authors: Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Jiangsu, The Key Laboratory of Monitoring and Management of Plant Diseases and Insects, Ministry of Agriculture, Nanjing, 210095, Jiangsu, China. Electronic address: zjhan@njau.edu.cn.
authors: Zhaojun
authors: Z
authors: Han
mesh_terms: D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics* / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D006430:Hemiptera / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D019476:Insect Proteins / Q000235:genetics* / Q000378:metabolism; D007305:Insecticide Resistance / Q000235:genetics*; D007306:Insecticides; D009570:Nitriles; D011722:Pyrethrins; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012045:Regulatory Sequences, Nucleic Acid; D015854:Up-Regulation
chemical_list: D018076:DNA, Complementary; D019476:Insect Proteins; D007306:Insecticides; D009570:Nitriles; D011722:Pyrethrins; D012333:RNA, Messenger; C017180:decamethrin; D003577:Cytochrome P-450 Enzyme System
keywords: Gene expression; Laodelphax striatellus; Monooxygenase; Promoter activity; Selective sweep; Transcription factor