Identification of differentially expressed immunity‐related genes in Monochamus alternatus Hope (Coleoptera: Cerambycidae) larvae parasitized by Dastarcus helophoroides (Fairmaire) (Coleoptera: Bothrideridae)

The pine sawyer Monochamus alternatus Hope (Coleoptera: Cerambycidae) is a serious pest of several Pinus species, and the ectoparasitoid larvae of Dastarcus helophoroides (Fairmaire) (Coleoptera: Bothrideridae) is an important natural enemy of this pest. The transcriptome of M . alternatus larvae was sequenced using the Illumina platform and immunity‐related genes were specifically analyzed. De novo assembly resulted in the identification of 24 241 unigenes, with a mean length of 1122 bp, in unparasitized M . alternatus larvae and 23 807 unigenes, with a mean length of 1140 bp, for parasitized larvae. Removal of redundant unigenes resulted in 26 095 all‐unigenes, of which 16 959 (64.99%) showed clear homology with some of the known genes in the National Center for Biotechnology Information nr database. Parasitization had notable effects on the transcriptome profile of M . alternatus larvae. In all, 2702 genes were differentially expressed in M . alternatus larvae after parasitization, with 1491 (55.18%) upregulated and 1211 (44.82%) downregulated. Moreover, expression levels of immunity‐related genes in M . alternatus larvae were markedly altered in response to parasitization by D . helophoroides . In conclusion, the transcriptome profiling data, especially the discovered of immunity‐related genes, help illustrate the molecular mechanisms of parasitism between D . helophoroides and M . alternatus and provide new insights into developing immunity regulation‐mediated control methods of M . alternatus .