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Open Access Research article

Antimicrobial peptide-like genes in Nasonia vitripennis: a genomic perspective

Caihuan Tian1, Bin Gao1, Qi Fang2, Gongyin Ye2 and Shunyi Zhu1*

Author Affiliations

1 Group of Animal Innate Immunity, State Key Laboratory of Integrated Management of Pest Insects & Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, PR China

2 State Key Laboratory of Rice Biology, Institute of Insect Sciences, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310029, PR China

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BMC Genomics 2010, 11:187  doi:10.1186/1471-2164-11-187

Published: 19 March 2010

Abstract

Background

Antimicrobial peptides (AMPs) are an essential component of innate immunity which can rapidly respond to diverse microbial pathogens. Insects, as a rich source of AMPs, attract great attention of scientists in both understanding of the basic biology of the immune system and searching molecular templates for anti-infective drug design. Despite a large number of AMPs have been identified from different insect species, little information in terms of these peptides is available from parasitic insects.

Results

By using integrated computational approaches to systemically mining the Hymenopteran parasitic wasp Nasonia vitripennis genome, we establish the first AMP repertoire whose members exhibit extensive sequence and structural diversity and can be distinguished into multiple molecular types, including insect and fungal defensin-like peptides (DLPs) with the cysteine-stabilized α-helical and β-sheet (CSαβ) fold; Pro- or Gly-rich abaecins and hymenoptaecins; horseshoe crab tachystatin-type AMPs with the inhibitor cystine knot (ICK) fold; and a linear α-helical peptide. Inducible expression pattern of seven N. vitripennis AMP genes were verified, and two representative peptides were synthesized and functionally identified to be antibacterial. In comparison with Apis mellifera (Hymenoptera) and several non-Hymenopteran model insects, N. vitripennis has evolved a complex antimicrobial immune system with more genes and larger protein precursors. Three classical strategies that are likely responsible for the complexity increase have been recognized: 1) Gene duplication; 2) Exon duplication; and 3) Exon-shuffling.

Conclusion

The present study established the N. vitripennis peptidome associated with antimicrobial immunity by using a combined computational and experimental strategy. As the first AMP repertoire of a parasitic wasp, our results offer a basic platform for further studying the immunological and evolutionary significances of these newly discovered AMP-like genes in this class of insects.