Comparative analysis of diet-associated responses in two rice planthopper species

Abstract Background: Host adaptation is the major determinant of insect diversification. However, knowledge of different host ranges in very close-related species remains scarce. The brown planthopper (Nilaparvata lugens, BPH) and small brown planthopper (Laodelphax striatellus, SBPH) are the most destructive insect pests belonging to Delphacidae. These two species differ in the host range (SBPH can well colonize on rice and wheat plants, while BPH survive on rice plants only), but the underlying mechanism still remains unknown. High-throughput sequencing technology provides a powerful approach for analyzing the association between gene expression changes and physiological responses of insects. Therefore, the gut transcriptomes were performed to elucidate the genes associated with host adaptation in planthoppers. Comparative analysis of planthoppers’ responses to different diets would improve our knowledge of host adaptation regarding herbivores insects.Results: In the present study, we analyzed the gene expression change of SBPH that transferred from rice plants to wheat plants in a short term (rSBPH vs tSBPH) and colonized on wheat plants for a long term (rSBPH vs wSBPH). The results showed that the majority of differentially expressed genes in SBPH showed similar expression change between short-term transfer and long-term colonization. Based on the comparative analysis of BPH and SBPH after transferring, genes associated with sugar transporters and heat shock proteins varied similarly. However, most of genes were differentially regulated between two species. The detoxification-related genes were upregulated in SBPH after transferring while downregulated in BPH under the same condition. Ribosomal-related genes were downregulated in SBPH after transferring while upregulated in BPH under the same condition.Conclusion: The results of this study provided evidence that host plants played dominant roles in shaping the gene expression, and unfitness of BPH on wheat plants might be determined within 24 hours after transferring. This study deepens our understanding of different host ranges regarding two planthopper species, which may provide a potential strategy for pest management.