Molecular characterization and expression profiles of nicotinic acetylcholine receptor genes in rice striped stem borer, Chilo suppressalis
Introducion: Nicotinic acetylcholine receptors (nAChRs) are members of the cys-loop ligand-gated ion channel (cysLGIC) superfamily, which mediate fast synaptic cholinergic transmission in the insect central nervous system and play roles in many cognitive processes. The insect nAChRs are the molecular targets of a class of insecticides, neonicotinoids. Like mammalian nAChRs, insect nAChRs are considered to be made up of two subunits, encoded by multiple α- and β subunit genes. The nAChR subunit genes of Drosophila melanogaster, Apis mellifera, Bombyx mori, Tribolium castaneum and Nasonia vitripennis have been cloned previously based on their genome sequences. The rice striped stem borer Chilo suppressalis is an important agricultural pest of Lepidoptera, which cause a serious loss to rice production in China. Identification and characterization of C. suppressalis nAChR genes could provide valuable information for this important family of receptor genes and for the study of the molecular modes of neonicotinoid action and resistance for current and future chemical control strategies.
Results: We searched our transcriptome database of C. suppressalis with the silkworm nAChRs by Blastp and cloned all putative nAChR genes by reverse transcriptase polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE). Like silkworm B. mori of Lepidoptera, C. suppressalis also have nine α-type subunits and three β-type subunits, which possesses two genes showing low identity with others, including β2 and β3. Semi-quantitative PCR and quantitative PCR reveals the expression profiles of nAChR genes in various tissues and at different developmental stages in C. suppressalis.
Conclusions: C. suppressalis possesses twelve nAChR genes as same as the silkworm B. mori , including nine α-type subunits and three β-type subunits. The different expression profiles of nAChR genes provides a foundational knowledge to explore and understand the molecular basis of nAChRs in this striped stem borer and for the study of molecular targets of agricultural pest.
Key Words: nAChRs, expression profiles, molecular targets, Chilo suppressalis
