Cookies

We use cookies to ensure that we give you the best experience on our website. By continuing to browse this repository, you give consent for essential cookies to be used. You can read more about our Privacy and Cookie Policy.


Durham Research Online
You are in:

Venom of parasitoid, Pteromalus puparum, suppresses host, Pieris rapae, immune promotion by decreasing host c-type lectin gene expression.

Fang, Q. and Wang, F. and Gatehouse, J.A. and Gatehouse, A.M.R. and Chen, X-X. and Hu, C. and Ye, G-Y. (2011) 'Venom of parasitoid, Pteromalus puparum, suppresses host, Pieris rapae, immune promotion by decreasing host c-type lectin gene expression.', PLoS ONE., 6 (10). e26888.

Abstract

Background: Insect hosts have evolved immunity against invasion by parasitoids, and in co-evolutionary response parasitoids have also developed strategies to overcome host immune systems. The mechanisms through which parasitoid venoms disrupt the promotion of host immunity are still unclear. We report here a new mechanism evolved by parasitoid Pteromalus puparum, whose venom inhibited the promotion of immunity in its host Pieris rapae (cabbage white butterfly). Methodology/Principal Findings: A full-length cDNA encoding a C-type lectin (Pr-CTL) was isolated from P. rapae. Quantitative PCR and immunoblotting showed that injection of bacterial and inert beads induced expression of Pr-CTL, with peaks of mRNA and Pr-CTL protein levels at 4 and 8 h post beads challenge, respectively. In contrast, parasitoid venom suppressed Pr-CTL expression when co-injected with beads, in a time and dose-dependent manner. Immunolocalization and immunoblotting results showed that Pr-CTL was first detectable in vesicles present in cytoplasm of granulocytes in host hemolymph, and was then secreted from cells into circulatory fluid. Finally, the secreted Pr-CTL bound to cellular membranes of both granulocytes and plasmatocytes. Injection of double-stranded RNA specific for target gene decreased expression of Pr-CTL, and a few other host immune-related genes. Suppression of Pr-CTL expression also down-regulated antimicrobial and phenoloxidase activities, and reducing phagocytotic and encapsulation rates in host. The inhibitory effect of parasitoid venom on host encapsulation is consistent with its effect in suppressing Pr-CTL expression. Binding assay results showed that recombinant Pr-CTL directly attached to the surface of P. puparum egges. We infer that Pr-CTL may serve as an immune signalling co-effector, first binding to parasitoid eggs, regulating expression of a set of immune-related genes and promoting host immunity. Conclusions/Significance: P. puparum venom inhibits promotion of host immune responses by silencing expression of host C-type lectin gene Pr-CTL, whose expression affected transcription of other host immune-related genes.

Item Type:Article
Full text:PDF - Published Version (2741Kb)
Status:Peer-reviewed
Publisher Web site:http://dx.doi.org/10.1371/journal.pone.0026888
Publisher statement:Copyright: © 2011 Fang et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Record Created:07 Jun 2012 15:20
Last Modified:08 Jun 2012 14:32

Social bookmarking: del.icio.usConnoteaBibSonomyCiteULikeFacebookTwitterExport: EndNote, Zotero | BibTex
Usage statisticsLook up in GoogleScholar | Find in a UK Library