Abstract: To isolate the differentially expressed genes in brown planthopper Nilaparvata lugens (Homoptera: Delphacidae) responding to host rice resistance, suppression subtractive hybridization (SSH) was carried out using the 4th instar larvae of brown planthopper feeding on the susceptible rice Taichung Native 1 (TN1) and the highly resistant rice B5 seedlings at the 3rd leaf stage for 24 h. A forward and a reverse subtracted cDNA libraries specific to host rice resistance were constructed, followed by differential screening by dot blot hybridization. The clones representing the regulated genes were sequenced and evaluated by nucleotide blast analysis in the GenBank. Expression of the clones highly homologous to the known genes in the database was further verified by Northern blot hybridization. The results showed that 92 out of 98 clones were identified as non-redundant expressed sequence tags (ESTs) by dot blot analysis, among which 25 ESTs had high homology (E value<0.01) to known genes in the GenBank. Northern blot hybridization analysis demonstrated that 11 of the 25 genes were induced and 8 were repressed by rice resistance, suggesting that these genes may play an important role in response of brown planthopper to resistant rice. The data obtained in this work will help to clone the full-length cDNA sequences of the novel genes and reveal their functions involved in rice resistance.

Key words: Brown planthopper (Nilaparvata lugens), host rice resistance, suppression subtractive hybridization (SSH), dot blot hybridization, differentially expressed gene