Molecular characterization of diapause hormone inHelicoverpa armigera

Diapause hormone (DH) is a neurohormone which is secreted from suboesophageal ganglion and responsible for induction of embryonic diapause in many insects. Using rapid amplification of the cDNA ends (RACE) method, the cDNA encoding diapause hormone inHelicoverpa armigera, a main kind of crops pest was cloned. The nucleotide sequence reveals that the mRNA encodes an open reading frame and the 25-aa DH peptide is localized at N-terminal region just after the signal peptide. A homology search showed thatH. armigera DH has high homology with the diapause hormone ofBombyx mori andHelicoverpa zea; and it also belongs to the FXPRL neuropeptide family. Thus,H. armigera DH seems to be a new type of diapause hormone molecule.