关键词: 甜菜夜蛾, 几丁质脱乙酰酶SeCDA7, 外源表达, 组织定位分析, 几丁质结合活性

Abstract: Chitin deacetylase（CDA）is an important component of insect chitin metabolism enzymes,thus recognized as the key target in pest control. RT-PCR method was used to clone a gene secda encoding CDA in Spodoptera exigua midgut. The secda was 1 431 bp in length,containing an ORF 1 134bp（GenBank accession number：MG604929）. After the signal peptide removed,the secreted SeCDA7 protein was predicted to have a molecular weight 43.156 kD. Domain analysis indicated that SeCDA7 had a polysaccharide acetyltransferase catalytic region belonging to the first class V CDA protein. Then,the prokaryotic and eukaryotic recombinant expression vectors were constructed,and Sf9 insect cells were infected using the Escherichia coli and Bac-to-Bac insect baculovirus expression system,and SeCDA7 was expressed successfully in the insect cells. The purification results of SeCDA7 protein and analysis of chitin binding activity showed that SeCDA7 protein had chitin binding activity. Fluorescence quantitative PCR results demonstrated that secda7 gene mainly expressed in the midgut. In sum,the heterogeneous expression of the chitin deacetylase gene secda7 in S. exigua is achieved and the SeCDA7 is identified to have chitin binding activity,which provides a theoretical basis for further investigation on the physiological function of the chitin deacetylase of S. exigua.

Key words: Spodoptera exigua, chitin deacetylase SeCDA7, exogenous expression, tissue localization analysis, chitin binding activity