Abstract: 【Aim】 SC1 (sodium channel 1) is an important ion channel in arthropods including insects. It is considered as a possible new neuro target. This study aims to investigate the SC1 gene from Rhopalosiphum padi, and to analyze the primary biological functions of the gene and the evolutionary relationship of SC1 channels with voltage-gated sodium channel and voltage-gated calcium channel. 【Methods】 RT-PCR technique was used to clone the full-length ORF of RC1 gene from R. padi. After R. padi adults were exposed to different concentrations of λ-cyhalothrin for 6 and 24 h, respectively, the expression levels of SC1 were analyzed by real-time quantitative PCR. 【Results】 The ORF of RSC1 (GenBank accession no: KU640190) is 6 687 bp in length with the deduced amino acid sequence of 2 228 residues. Structural analysis showed that the RSC1 has the typical structural feature of SC1 channel, and contains a unique DEEA motif, which is different from the motif of sodium channel and calcium channel. Phylogenetic analysis indicated that RSC1 and its orthologs from other animals consist of a sub-group, which is more similar to the sodium channel family. In R. padi adults exposed to λ-cyhalothrin for 6 h, the expression level of RSC1 gene significantly decreased to 0.57-, 0.82- and 0.78-fold that of the control, respectively, while increased to 2.19-, 1.33- and 1.19-fold that of the control, respectively, after 24 h insecticide exposure. The expression level of RSC1 significantly increased in R. padi adults exposed to λ-cyhalothrin at the dosage of LC₁₅ (0.1484 mg/L). 【Conclusion】 The SC1 channel family are evolutionarily closer to the voltage-gated sodium channel family. RSC1 is the possible secondary target of λ-cyhalothrin. Since RSC1 gene and its orthologs have been found in invertebrates but not in vertebrates, these channels can be used as neurotarget to develop novel insecticides.      

Key words: Key words: Rhopalosiphum padi, RSC1 channel, gene cloning, induced expression, insecticide target