Characterization and regulation of expression of an antifungal peptide from hemolymph of an insect, Manduca sexta

Qasim Al Souhail, Yasuaki Hiromasa, Mohammad Rahnamaeian, Martha C. Giraldo, Daisuke Takahashi, Barbara Valent, Andreas Vilcinskas, Michael R. Kanost

Research output: Contribution to journalArticlepeer-review

31 Citations (Scopus)


Insects secrete antimicrobial peptides as part of the innate immune response. Most antimicrobial peptides from insects have antibacterial but not antifungal activity. We have characterized an antifungal peptide, diapausin-1 from hemolymph of a lepidopteran insect, Manduca sexta (tobacco hornworm). Diapausin-1 was isolated by size exclusion chromatography from hemolymph plasma of larvae that were previously injected with a yeast, Saccharomyces cerevisiae. Fractions containing activity against S. cerevisiae were analyzed by SDS-PAGE and MALDI-TOF MS/MS and found to contain a 45-residue peptide that was encoded by sequences identified in M. sexta transcriptome and genome databases. A cDNA for diapausin-1 was cloned from cDNA prepared from fat body RNA. Diapausin-1 is a member of the diapausin family of peptides, which includes members known to have antifungal activity. The M. sexta genome contains 14 genes with high similarity to diapausin-1, each with 6 conserved Cys residues. Diapausin-1 was produced as a recombinant protein in Escherichia coli. Purified recombinant diapausin-1 was active against S. cerevisiae, with IC50 of 12 μM, but had no detectable activity against bacteria. Spores of some plant fungal pathogens treated with diapausin-1 had curled germination tubes or reduced and branched hyphal growth. Diapausin-1 mRNA level in fat body strongly increased after larvae were injected with yeast or with Micrococcus luteus. In addition, diapausin-1 mRNA levels increased in midgut and fat body at the wandering larval stage prior to pupation, suggesting developmental regulation of the gene. Our results indicate that synthesis of diapausin-1 is part of an antifungal innate immune response to infection in M. sexta.

Original languageEnglish
Pages (from-to)258-268
Number of pages11
JournalDevelopmental and Comparative Immunology
Publication statusPublished - Aug 1 2016
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Immunology
  • Developmental Biology


Dive into the research topics of 'Characterization and regulation of expression of an antifungal peptide from hemolymph of an insect, Manduca sexta'. Together they form a unique fingerprint.

Cite this