Comparative analysis of different host adaptation 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 is 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, but the underlying mechanism remains unknown. Comparative analysis of planthoppers’ responses to different diets would improve our knowledge of host adaptation regarding herbivores insects.Results: SBPH could well colonize on rice and wheat plants, while BPH survived on rice plants only. 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). We found 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 reciprocally regulated between two species. The detoxification-related genes were upregulated in SBPH after transferring, but downregulated in BPH under the same condition; ribosomal-related genes were down regulated in SBPH after transferring, but 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, with alike responding of most genes between short-term transfer and long-term colonization in SBPH. In contrast, the majority of genes in BPH were reciprocally regulated in comparison to those of SBPH, 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, and may provide a potential strategy for pest management.