Abstract: The brown planthopper (BPH), Nilaparvata lugens (Stål), is an important rice damaging pest. Secretions by salivary glands of the BPH in the process of feeding rice contain some substances that can elicit a series of physiological and biochemical reactions of rice plants. In order to obtain the genes that encode such secretions, a suppressed subtractive hybridization (SSH) library including 768 clones was constructed by SSH and mirror orientation selection (MOS) methods with the BPH fed on the insect-resistant rice B5 as the tester and that fed on the insect-susceptible rice TN1 as the driver. The SSH library contained a total of 102 ESTs with insertions of 250-1 000 bp including 35 unigenes, among which 28 were up-regulated while 7 down-regulated. Through analysis by online tool blastx in the GenBank database, we found that the amino acid sequences represented by 2/3 of ESTs showed similarities in different degrees with some known proteins, such as trehalase, vitellogenin, calcium ion binding protein, cathepsin B, putative mucin-like protein, carboxylesterase, and cah-3 carbonic anhydrase. Most of the predicted proteins had signal peptides that might be related to secretion. This study laid a foundation for further research of elicitor proteins of this piercing-sucking insect.

Key words: Nilaparvata lugens, insect-resistant rice, host resistance adaptation genes, elicitor, suppressed subtractive hybridization (SSH), mirror orientation selection (MOS)