Relative mRNA abundance of nine target genes after injecting siRNAs.

<p>The mRNA levels of target genes were monitored by qRT-PCR at 24, 48, 72, 96 and 120 h after injection. Three insects were collected for each time point. The data for PGCP at 24 h, chitinase 1 at 96 h, and tubulin2 at 120 h are absent because of the unsuccessful RNA purification. Larvae injected with siRNA with a random sequence were used as negative controls. Two housekeeping genes, G3PDH and E2F, were used as multiple internal controls. The qRT-PCR data were analyzed using the delta-delta Ct method. The mRNA abundance of target genes in the negative control was used as the calibrator sample. The mRNA levels of target genes in the siRNA-treated group were relative to the negative control group at the same time point. Error bars indicate standard errors. Statistical significance of differences were analyzed with student T-test (decreasing significance,* P<0.05, **P<0.01; increasing significance, # P<0.05 ).