title: Altered gene regulation and potential association with metabolic resistance development to imidacloprid in the tarnished plant bug, Lygus lineolaris.
abstract: BACKGROUND
  Chemical spray on cotton is almost an exclusive method for controlling tarnished plant bug (TPB), Lygus lineolaris. Frequent use of imidacloprid is a concern for neonicotinoid resistance in this key pest. Information of how and why TPB becomes less susceptible to imidacloprid is essential for effective monitoring and managing resistance.
  
  
  RESULTS
  Microarray analysis of 6688 genes in imidacloprid-selected TPB (Im1500FF) revealed 955 upregulated and 1277 downregulated (≥twofold) genes in Im1500FF, with 369 and 485 of them annotated. Five P450 and nine esterase genes were significantly upregulated, and only one esterase gene and no P450 genes were downregulated. Other upregulated genes include helicases, phosphodiesterases, ATPases and kinases. Pathway analyses identified 65 upregulated cDNAs that encode 51 different enzymes involved in 62 different pathways, including P450 and esterase genes for drug and xenobiotic metabolisms. Sixty-four downregulated cDNAs code only 17 enzymes that are associated with only 23 pathways mostly related to food digestion.
  
  
  CONCLUSIONS
  This study demonstrated a significant change in gene expression related to metabolic processes in imidacloprid-selected TPB, resulting in overexpression of P450 and esterase genes for potential excess detoxification and cross/multiple resistance development. The identification of these and other enzyme genes establishes a foundation to explore the complicity of potential imidacloprid resistance in TPB.
authors: USDA-ARS-JWDSRC, Stoneville, MS, USA.
authors: Yu Cheng
authors: YC
authors: Zhu
authors: Randall
authors: R
authors: Luttrell
mesh_terms: D000818:Animals; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D006430:Hemiptera / Q000235:genetics / Q000378:metabolism*; D007093:Imidazoles; D008658:Inactivation, Metabolic; D007305:Insecticide Resistance; D007306:Insecticides; D058977:Molecular Sequence Annotation; D000073943:Neonicotinoids; D009574:Nitro Compounds; D020411:Oligonucleotide Array Sequence Analysis
chemical_list: D007093:Imidazoles; D007306:Insecticides; D000073943:Neonicotinoids; D009574:Nitro Compounds; C082359:imidacloprid
keywords: Lygus lineolaris; P450; cDNA; esterase; imidacloprid; microarray; resistance; susceptibility; tarnished plant bug