Figure 1

Pyrethroid resistance-associated amino acid substitutions in sodium channels of Sitophilus spp weevils. (A) Schematic representation of insect voltage-gated sodium channels (VGSC) indicating two knockdown (kdr) resistance mutations (T929I and L1014F) as well as the positions of the sequenced fragments (a-f). The sodium channel protein is consisted of four homologous repeats (I - IV), each having six transmembrane segments (S1-S6). The isoleucine, phenylalanine and methionine motif (IFM) has a crucial role in the VGSC inactivation. Residue positions correspond to the house fly numbering (GenBank number: X96668). (B) Alignment of the deduced amino acid sequences of the region encompassing Domain II S5-S6 (in grey) of S. zeamais and S. oryzae with Drosophila melanogaster para sodium channel proteins. Dashes represent identical residues. The positions of the encountered mutations (T929 and F1014) are in Red.