<i>BmSpry</i> was essential for antiviral defense <i>in vivo</i>.

<p>(A) The silkworm Nm DZ line was used for the RNAi experiment. Injection of dsRNA is indicated, the dsRNA of dsRed was used as a negative control with dsRNA of <i>BmSpry</i> as the experimental group. At 3 days post-injection of dsRNA, total RNA was extracted for qPCR to measure the expression level of <i>BmSpry</i>. Data are given as mean ±SD (<i>n</i> = 3). (B) Nm DZ silkworms treated with dsRNA against the indicated genes were infected with BmNPV (10<sup>6</sup> pfu/mL) by stab inoculation for 3 days and processed for qPCR. Data are given as mean ±SD (<i>n</i> = 3). (C) Analysis of the expression level of <i>BmSpry</i> in Nm DZ and the mutant DZ SN. Total RNA extracted from newly exuviated Nm DZ and DZ SN 5th instar larvae was used for qPCR. Data are given as mean ±SD (<i>n</i> = 3). (D) Analysis of mortality of DZ SN and Nm DZ after oral inoculation with BmNPV. Nm DZ and DZ SN newly exuviated 4th instar larvae were used for this experiment. DZ SN and Nm DZ silkworms were infected with BmNPV <i>per os</i> using a dose of 10<sup>4</sup> or 10<sup>6</sup> OB/larva and mortality was monitored until the adult stage (22 days). (E) Newly exuviated 2nd-instar larvae were used to investigate mortality after inoculation <i>per os</i> with 5×10<sup>3</sup> OB/larva. Mortality was monitored until the pupa stage (16 days). A representative of triplicate experiments is shown. Statistically significant differences: ** P<0.01.</p>