Abstract: RNA interference （RNAi） has been demonstrated to be used to interfere special life processes by silencing target genes. Therefore, a new countermeasure of RNAi pest control could be developed through exploring effective specific target genes and efficient RNAi techniques. Based on transcriptome data analysis and RACE strategy, two full-length trehalase genes were cloned from the small brown plant hopper (SBPH), Laodelphax striatellus, and were designated as LSTre-1 and LSTre-2, with GenBank accession numbers JQ027050 and JQ027051, respectively. Both LSTre-1 and LSTre-2 have typical characteristics of trehalase genes, and show high sequence identity with trehalase genes in other insects. LSTre-1 is 2 024 bp in length, and its ORF encodes a protein of 602 amino acids including a signal peptide of 25 amino acids and without hydrophobic transmembrane domains. LSTre-2 is 2 619 bp in length, and its ORF encodes a protein of 618 amino acids including a signal peptide of 26 amino acids and two hydrophobic transmembrane domains. Double-stranded RNA （dsRNA） was synthesized based on these two genes and the toxicological effects of RNAi were studied. The results showed that the silencing effect of LSTre-1 dsRNA was higher than that of LSTre-2 dsRNA. However, silencing of these two genes all can not only cause lethal effect by decreasing the mRNA expression and enzyme activity but also prevent the normal growth and development of SBPH. These results imply that SBPH could be controlled through silencing its trehalase genes by feeding dsRNA with proper ways.

Key words: Laodelphax striatellus, trehalase, dsRNA, RNA interference, lethal effect