Identification and function analysis of chitinase 2 gene in housefly, Musca domestica.

Chitinases are hydrolytic enzymes that play important roles in chitin degradation during the insect development process, and thus are considered as the potential targets for pest management. Here, we identified and characterized the group VII chitinase gene from health pest Musca domestica (MdCht2). We found that MdCht2 was 1932 bp in length with an open reading frame of 1530 bp, which encodes a polypeptide of 509 amino acid residues. Phylogenetic analysis showed that MdCht2 gene was homologs with other closed insects, and belong to the group VII chitinases. Moreover, Real-time PCR analysis indicated that MdCht2 mRNA was highly expressed in pupa stage, as well as in integument and trachea. However, RNAi-mediated knockdown of MdCht2 resulted in high mortality rates and abnormal eclosion. Therefore, we hypothesized that MdCht2 was a crucial gene required for housefly development, which was supported by the transcription level of MdCht2 could be induced by 20-hydroxyecdysone (20E), and the dsMdCht2 could resulted in decrease of the chitinase activity and increase of the chitin content. Taken together, our findings suggested that MdCht2 regulated the chitin content via chitinases, thereby leading to abnormal development. Our results provide a potential target for M. domestica management.