Abstract: Expressed sequence tags (ESTs) are important resources for development of new SSR markers. In this study, 37 398 ESTs of Nilaparvata lugens (Stål) were downloaded from NCBI and analyzed. After the pre-procession, 9 852 non-redundant ESTs with the total length about 7 619 324 kb were obtained. The EST-SSRs were detected under three search qualifications. The search results indicated that the 1-3 repeat motifs were the major repeats among all the SSRs, which accounted for above 95% of all EST-SSRs. A/T was the most frequent motif in the mononucleotide AG/CT and AAG/CTT were the major motifs in the dinucleotide and trinucleotide, respectively. The GC repeat motif was not found in the EST-SSRs of N. lugens. When 100 bp was used as the comparison, the numbers of sequences with both flanking regions ≥100 bp under three search qualifications were 738, 89, and 42, respectively. The analysis of EST-SSRs markers can provide the information for the SSR development of N. lugens and related species. Furthermore, the analysis of the distribution frequency and character of N. lugens EST-SSRs can provide help for the EST-SSRs study of insects.

Key words: Nilaparvata lugens, bioinformatics, EST, EST-SSRs, search qualification, repeat motif