关键词: 亚洲玉米螟, C型凝集素, CTL6, 天然免疫反应, 凝集作用

Abstract: 【Aim】 This study aims to identify a C-type lectin in Ostrinia furnacalis (Guenée) and to investigate its function. 【Methods】 A potential C-type lectin gene was identified from O. furnacalis transcriptome with bioinformatics analysis and designated as CTL6. Its expression profiles in different developmental stages and tissues and after different pathogen induction in this insect were analyzed with RT-PCR. The recombinant CTL6 protein was produced in the prokaryotic or baculovirus eukaryotic expression system, and its function was investigated preliminarily with bacterial agglutination assay. 【Results】 The full-length cDNA of CTL 6 is 1 034 nt, with an open reading frame of 945 nt. The deduced protein consists of 314 amino acid residues, including a predicted 22-residue secretion signal peptide. The mature CTL6 peptide contains two carbohydrate recognition domains. Database search indicated that O. furnacalis CTL6 has the highest amino acid sequence identity to IML-2 (Immulectin-2) from Manduca sexta. RT-PCR results showed that CTL 6 was transcribed at the highest level in the 5th instar larval stage, followed by the egg stage, and its expression level in the fat body was the highest among the tested tissues. CTL 6 mRNA level obviously increased after bacterial or fungal injection. Agglutination assay revealed that the purified CTL6 recombinant protein played a role in the agglutination of Escherichia coli. 【Conclusion】 The identified O. furnacalis CTL6 is a typical C-type lectin, which may be involved in the agglutination response of O. furnacalis against pathogens.

Key words: Ostrinia furnacalis , C-type lectin, CTL6, innate immune response, agglutination response