This article is a US Government work, and, as such, is in the public domain in the United States of America.
Article first published online: 16 MAY 2005
Published 2005 Wiley-Liss, Inc.
Archives of Insect Biochemistry and Physiology
Volume 59, Issue 2, pages 67–79, June 2005
How to Cite
Hartzer, K. L., Zhu, K. Y. and Baker, J. E. (2005), Phenoloxidase in larvae of Plodia interpunctella (Lepidoptera: Pyralidae): Molecular cloning of the proenzyme cDNA and enzyme activity in larvae paralyzed and parasitized by Habrobracon hebetor (Hymenoptera: Braconidae) . Arch. Insect Biochem. Physiol., 59: 67–79. doi: 10.1002/arch.20056
Mention of trade names or commercial products in this paper is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture.
The complete nucleotide sequence of Plodia interpunctella PPO1 cDNA can be accessed through the NCBI-GenBank database, Accession Number AY665397.
- Issue published online: 16 MAY 2005
- Article first published online: 16 MAY 2005
- Manuscript Accepted: 6 FEB 2005
- Manuscript Received: 4 NOV 2004
- Plodia interpunctella;
- immune system;
Phenoloxidase (PO) is a major component of the insect immune system. The enzyme is involved in encapsulation and melanization processes as well as wound healing and cuticle sclerotization. PO is present as an inactive proenzyme, prophenoloxidase (PPO), which is activated via a protease cascade. In this study, we have cloned a full-length PPO1 cDNA and a partial PPO2 cDNA from the Indianmeal moth, Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae) and documented changes in PO activity in larvae paralyzed and parasitized by the ectoparasitoid Habrobracon hebetor (Say) (Hymenoptera: Braconidae). The cDNA for PPO1 is 2,748 bp and encodes a protein of 681 amino acids with a calculated molecular weight of 78,328 and pI of 6.41 containing a conserved proteolytic cleavage site found in other PPOs. P. interpunctella PPO1 ranges from 71–78% identical to other known lepidopteran PPO-1 sequences. Percent identity decreases as comparisons are made to PPO-1 of more divergent species in the orders Diptera (Aa-48; As-49; and Sb-60%) and Coleoptera (Tm-58; Hd-50%). Paralyzation of host larvae of P. interpunctella by the idiobiont H. hebetor results in an increase in phenoloxidase activity in host hemolymph, a process that may protect the host from microbial infection during self-provisioning by this wasp. Subsequent parasitization by H. hebetor larvae causes a decrease in hemolymph PO activity, which suggests that the larval parasitoid may be secreting an immunosuppressant into the host larva during feeding. Arch. Insect Biochem. Physiol. 59:67–79, 2005. Published 2005 Wiley-Liss, Inc.