Cloning, Expression and Analysis of a Novel Defense Gene from Antheraea pernyi

Abstact.In this study, we first reported the defense gene (ApDef) in lepidoptera insect, the Chinese oak silkworm Antheraea pernyi (Lepidoptera: Saturniidae). It consists of 677 bp with a putative open reading frame (ORF) of 492 bp encoding 163 amino acids residues. A signal peptide with 18 amino acids and a typical reeler domain was found in ApDef protein. Phylogenetic analysis indicated that ApDef gene had the closest genetic distance with Antheraea mylitta Defense. The results of real-time quantitative PCR (qRT-PCR) showed that this gene was highly expressed in fat body, low expressed in hemocytes and midgut, and not expressed in epidermis. After being challenged by three types of pathogens (Escherichia coli, Micrococcus luteus and Beauveria bassiana), the expression levels of ApDef were up-regulated significantly compared with the control, and reached the maximum at 12 h post infection. These data indicated that ApDef may play an important role in innate immune responses of A. pernyi .