title: Effect of insecticidal fusion proteins containing spider toxins targeting sodium and calcium ion channels on pyrethroid-resistant strains of peach-potato aphid (Myzus persicae).
abstract: BACKGROUND
  The recombinant fusion proteins Pl1a/GNA and Hv1a/GNA contain the spider venom peptides δ-amaurobitoxin-PI1a or ω-hexatoxin-Hv1a respectively, linked to snowdrop lectin (GNA). Pl1a targets receptor site 4 of insect voltage-gated sodium channels (NaCh), while Hv1a targets voltage-gated calcium channels. Insecticide-resistant strains of peach-potato aphid (Myzus persicae) contain mutations in NaCh. The pyrethroid-resistant kdr (794J) and super-kdr (UKO) strains contain mutations at residues L1014 and M918 in the channel α-subunit respectively, while the kdr + super-kdr strain (4824J), insensitive to pyrethroids, contains mutations at both L1014 and M918.
  
  
  RESULTS
  Pl1a/GNA and Hv1a/GNA fusion proteins have estimated LC50 values of 0.35 and 0.19 mg mL(-1) when fed to wild-type M. persicae. For insecticide-resistant aphids, LC50 for the Pl1a/GNA fusion protein increased by 2-6-fold, correlating with pyrethroid resistance (wild type < kdr < super-kdr < kdr + super-kdr strains). In contrast, LC50 for the Hv1a/GNA fusion protein showed limited correlation with pyrethroid resistance.
  
  
  CONCLUSIONS
  Mutations in the sodium channel in pyrethroid-resistant aphids also protect against a fusion protein containing a sodium-channel-specific toxin, in spite of differences in ligand-channel interactions, but do not confer resistance to a fusion protein targeting calcium channels. The use of fusion proteins with differing targets could play a role in managing pesticide resistance.
authors: School of Biological and Biomedical Sciences, Durham University, Durham, UK.
authors: Sheng
authors: S
authors: Yang
authors: Food and Environment Research Agency (Fera), Sand Hutton, York, UK.
authors: Elaine
authors: E
authors: Fitches
authors: School of Biological and Biomedical Sciences, Durham University, Durham, UK.
authors: Prashant
authors: P
authors: Pyati
authors: School of Biological and Biomedical Sciences, Durham University, Durham, UK.
authors: John A
authors: JA
authors: Gatehouse
mesh_terms: D000818:Animals; D001042:Aphids / Q000187:drug effects* / Q000235:genetics; D015220:Calcium Channels / Q000235:genetics*; D007305:Insecticide Resistance / Q000235:genetics; D007306:Insecticides; D009154:Mutation; D011993:Recombinant Fusion Proteins / Q000235:genetics; D013111:Spider Venoms / Q000235:genetics*; D061566:Voltage-Gated Sodium Channels / Q000235:genetics*
chemical_list: D015220:Calcium Channels; D007306:Insecticides; D011993:Recombinant Fusion Proteins; D013111:Spider Venoms; D061566:Voltage-Gated Sodium Channels
keywords: Homoptera/Hemiptera; biopesticide; fitness cost; insecticide resistance; voltage-gated ion channels