A transferrin gene associated with development and 2-tridecanone tolerance in Helicoverpa armigera

The full-length cDNA (2320 bp) encoding a putative iron-binding transferrin protein from Helicoverpa armigera was cloned and named HaTrf. The putative HaTrf sequence included 670 amino acids with a molecular mass of approximately 76 kDa. Quantitative PCR results demonstrated that the transcriptional level of HaTrf was significantly higher in the sixth instar and pupa stages as compared with other developmental stages. HaTrf transcripts were more abundant in fat bodies and in the epidermis than in malpighian tubules. Compared with the control, the expression of HaTrf increased dramatically 24 h after treatment with 2-tridecanone. Apparent growth inhibition with a dramatic body weight decrease was observed in larvae fed with HaTrf double-stranded RNA (dsRNA), as compared with those fed with green fluorescent protein dsRNA. RNA interference of HaTrf also significantly increased the susceptibility of larvae to 2-tridecanone. These results indicate the possible involvement of HaTrf in tolerance to plant secondary chemicals.