THE ENDOPARASITOID Pteromalus puparum INFLUENCES HOST GENE EXPRESSION WITHIN FIRST HOUR OF PARASITIZATION

Abstract

The small cabbage butterfly, Pieris rapae, is an important pest of cruciferous corps, and Pteromalus puparum is a predominant pupal endoparasitoid wasp of this butterfly. For successful development of parasitoid offspring, female parasitoids usually introduce one or several kinds of maternal factors into the hemocoels during oviposition to suppress host immunity. To investigate the early changes in host immune-related genes following parasitization, we analyzed transcriptomes of parasitized and unparasitized, control, host pupae. Approximately 17.7 and 19.3 million paired-end reads were generated from nonparasitized and parasitized host pupae, and assembled de novo into 45,639 transcripts and 27,659 nonredundant unigenes. The average unigene length was 790 bp. A total 18,377 of 27,659 unigenes were annotated and we identified 557 differentially expressed unigenes in host pupae at 1 h after parasitization, of which 21 were immune-related. Parasitization led to downregulation of most pattern recognition receptors and upregulation of all serine protease inhibitors. The transcirptomic profile of P. rapae is considerably affected by parasitization. This study provides valuable sources for future investigations of the molecular interaction between P. puparum and its host P. rapae.

A Venom Serpin Splicing Isoform of the Endoparasitoid Wasp Pteromalus puparum Suppresses Host Prophenoloxidase Cascade by Forming Complexes with Host Hemolymph Proteinases

“…OfSP13 is the best reciprocal hit to PrPAP1 when reciprocal blastn was performed between O. furnacalis (50) and P. rapae transcriptome (33). OfSP13 has already been demonstrated to cleave PPO into PO and play an important role in PPO activation (44,51).…”

“…Other virulence factors found in some parasitoids, such as PDVs, virus-like particles, or teratocytes, have not been recorded in P. puparum (29). As the major maternal virulence factor in P. puparum, P. puparum venom regulates host development and metabolism (30) and suppresses cellular (27,28,31) and humoral immunity of the host (32)(33)(34). Here we report a serpin gene with 16 predicted splicing isoforms in P. puparum and show that one of these isoforms is a venom protein, which inhibits host PPO activation by forming complexes with host hemolymph proteinases.…”

Analysis of the Gynaephora qinghaiensis pupae immune transcriptome in response to parasitization by Thektogaster sp

“…In the present study, PRR transcripts encoding PGRPs, βGRPs, CTLs, and Dscam were downregulated in parasitized G. qinghaiensis pupae. The expression levels of PGRPs and βGRPs are downregulated in P. rapae pupae after 1 hr of parasitoid attack (Y. Zhu et al, ). In contrast, J. Y. Zhu et al () found that the expression of both PGRP‐ and βGRP‐encoding genes in Tenebrio molitor is upregulated after parasitization by Scleroderma guani .…”

“…Several studies have reported changes in host transcriptional profiles after parasitization and identified many characteristic genes related to parasitization in parasitic wasps and hosts. Y. Zhu et al () used RNA‐Seq to analyze changes in the immune‐related gene expression profile in P. rapae parasitized early by P. puparum . Wu et al () applied comparative transcriptome analyses using the RNA‐Seq in Chilo suppressalis parasitized by Cotesia chilonis .…”

“…Many chemoreception‐related genes have been obtained in the C. chilonis endoparasitoid wasp (Qi et al, ) and many genes involved in lipid metabolism have been identified in the Aphis gossypii pest parasitized by Lysiphlebia japonica based on RNA‐Seq (Gao et al, ). However, the biology of parasitization is complex (Y. Zhu et al, ) and the host response induced by the parasitoid is species‐specific (L. F. Li et al, ). Moreover, little genetic information is available for G. qinghaiensis , which has led to a lack of studies on immune‐related gene expression changes in G. qinghaiensis pupae after parasitization.…”