| Spodoptera frugiperda is a worldwide agricultural pest,damaging more than 353 host plants and causing devastating damage to major economic crops.Pyemotes zhonghuajia is a dominant natural enemy in China,which can effectively parasitize Lepidoptera,Coleoptera and Hymenoptera pests.Previous studies find that P.zhonghuajia could kill the eggs,larvae,prepupa and pupa of S.frugiperda.However,there is no report about the parasitism of P.zhonghuajia on the immune response of S.frugiperda.In this study,the effects of P.zhonghuajia parasitism on the cellular immune response and humoral immune response of S.frugiperda were studied,and the sequencing analysis of transcriptome and proteome were carried out on the 5th instar larvae of S.frugiperda 24 h after parasitism.The differential genes and proteins related to immunity were screened.The differential genes and proteins related to immunity were identified to provide theoretical support for the research on the inhibitory mechanism of P.zhonghuajia against the immune response of S.frugiperda.1.The Parasitism of Pyemotes zhonghuajia on Immune Response of Spodoptera frugiperdaThe host’s cellular and humoral immunity decreased after the larvae parasitized by P.zhonghuajia.The total number of blood cells in host larvae was significantly higher than that in the control group after parasitism,and reached the highest at 2 h after parasitism,and decreased after 2 h.The extension rate of host blood cells after parasitism was significantly lower than that of unparasitized larvae,and the mortality rate of host blood cells was significantly higher than that of the control group.In addition,the phagocytosis ability and encapsulation ability of host blood cells were significantly lower than those of the control group after parasitized,and the inhibition degree of melanization was aggravated,and the melanization rate of host blood cells was significantly lower than that of the control group.The activity of phenol oxidase was inhibited,and the activity of blood cells after being parasitized was significantly lower than that of the control group.2.The parasitism of Pyemotes zhonghuajia on transcriptome expression level of Spodoptera frugiperda and identification of immune-related genesEukaryotic non-parametric transcriptome sequencing technology was used to perform transcriptome sequencing on the 5th instar larvae of S.frugiperda and the non-parasitic group after the parasitism of 10 and 40 P.zhonghuajia at 24 h.The original data obtained were subjected to quality control to obtain 55309 Unigenes.The Unigenes were matched to five databases,Nr,Pfam,Swiss-prot,KEGG and GO for functional annotation,360 Unigenes were co-annotated in the five databases.Homologous alignment showed that the Unigenes annotated to S.litura species were the most.Compared with the control group,1287 genes were differentially expressed in 10 P.zhonghuajia parasitized groups,of which 552 were up-regulated and 735 were down-regulated.A total of 1774 differentially expressed genes were identified in the 40 parasitic groups of P.zhonghuajia,of which 777 were up-regulated and 997 were down-regulated.There were 138 differentially expressed genes in both treatment groups,of which 55 were up-regulated and 83 were down-regulated.Based on GO enrichment and KEGG enrichment analysis,we obtained the taxonomic functions and enrichment pathways of differentially expressed genes,identified immune-related genes,and verified the relative expression trends of 15 differentially expressed genes by q RT-PCR,respectively.The results showed that 12 genes were basically consistent with the transcriptome sequencing data,indicating that the transcriptome sequencing data were reliable.3.Effect of Parasitism on Proteome Expression of Spodoptera frugiperda and Screening of Immune-Related ProteinsProteome sequencing was performed on the 5th instar larvae and non-parasitized groups of 10 and 40 P.zhonghuajia parasitized for 24 h.The obtained proteins were4341 quantitative proteins.Differential analysis of the obtained proteins showed that a total of 74 differentially expressed proteins were screened between the 10 P.zhonghuajia parasitic and the control group,with 40 up-regulated and 34 downregulated proteins.A total of 247 differentially expressed proteins were screened between the 40 P.zhonghuajia parasitic and the control group,135 up-regulated and46 down-regulated;a total of 97 differential proteins were screened between 10 and40 P.zhonghuajia,51 up-regulated and 46 down-regulated.Based on GO enrichment and KEGG enrichment analysis,the classification function and enrichment pathway of differential genes were obtained,and the immune-related proteins were identified.Combined with omics analysis,compared with the control group,the co-up-regulated immunoproteins in the 10 P.zhonghuajia parasitic group were serine protease inhibitor-Z4,and the co-up-regulated immunoproteins in the 40 P.zhonghuajia parasitic group were small heat shock protein 27.2,serine protease inhibitor 77 Ba,small heat shock protein,plasminogen activator inhibitor 2,macrophage-like,cytochrome P450 and lectin C-type domain. |
