Abstract: Chloride channel was closely related to insect resistance to pesticides. ESTs of glutamate mediated chloride channel (GluCl) gene were clustered and identified from transcriptome data of Phyllotreta striolata (Fabricius). The expression of GluCl gene in different tissues of P. striolata adults was profiled by quantitative real-time PCR. The results indicated that the cDNA of this gene is 1 430 bp in length with an open reading frame (ORF) encoding 447 amino acids. The putative protein molecule contains two functional domains: a neurotransmitter-gate ion-channel ligation binding domain and a neurotransmittergate ion-channel transmembrane domain. There are two cysteine loops in ligation binding domain regions demonstrating a typical characteristic of GluClα subunit. Phylogenetic analysis of the complete cDNA sequence showed that the GluCl of P. striolata is highly homologous to GluClα of other insects. Quantitative real-time PCR assay showed that a relatively higher expression amount of GluCl gene was found in head than in other organs including antenna, midgut, testis, ovary, fore legs, middle legs and hind legs. The expression level of GluCl gene in head of male adult was 65.7 times as high as that in testis and 227.5 times in midgut, suggesting its important mediation in center nervous system. This study provides useful information for studying molecular mechanism of pesticide resistance mediated by GluCl of P. striolata.

Key words: Phyllotreta striolata, pesticide resistance, glutamate-gated chloride channel (GluCl), α-subunit； real-time PCR