Influence of SRPN7 and CLIPC2 silencing on mosquito resistance to bacterial challenge and midgut microbiota proliferation.

Adult female mosquitoes were subjected to RNAi-mediated depletion of SRPN7 or CLIPC2 transcripts and then challenged with (A) either Gram-positive Staphylococcus aureus or (B) Gram-negative Escherichia coli bacteria. Depletion of SRPN7 (p = 0.56) or CLIPC2 (p = 0.028) had no effect on the survival of mosquitoes challenged with (A) S. aureus, whereas there was a significant increase (p<0.01) in the survival of CLIPC2-depleted mosquitoes challenged with (B) E. coli but not SRPN7-depleted mosquitoes (p = 0.18). For both (A) and (B), data were pooled from three independent biological replicates (for A, n = 145; for B, n = 111), and a control group injected with dsGFP RNA was included in each replicate. Statistical significance was determined using Kaplan-Meier survival analysis with a log-rank test using Bonferonni's correction for multiple comparisons (significance  = p<0.025. (C) RNAi-mediated gene silencing of SRPN7 or CLIP2 resulted in a significant decrease (p<0.05) in the colony forming units (CFU) of cultivable midgut bacteria when compared to dsGFP-injected control mosquito midguts. Data were pooled from three independent biological replicates (n = 27 for each dsRNA group), and statistical significance was determined by one-way ANOVA followed by Dunnett's multiple comparison test. Error bars represent the standard error of the mean.