Figure 5. The influence of Pe. chrysogenum on Plasmodium infection is microbiota-independent.

P. falciparum infection intensity, as measured by oocyst numbers at 7 days after feeding on a gametocyte culture, was significantly higher in (A) Pe. chrysogenum conidia-exposed mosquitoes (N = 72, P = 0.0001) and (B) fungus culture filtrate-exposed (N = 75, P = 0.0009) mosquitoes than in their respective bacteria-void, antibiotic-treated non-Pe. chrysogenum-exposed controls (N = 87, N = 59, respectively). Graphs show three independent biological replicates; each dot represents a single midgut, and horizontal bars represent the median infection intensity. ***P < 0.001, ****P < 0.0001; two-tailed Mann-Whitney test. (C) Midgut bacterial load, as measured by colony forming units (CFU), was significantly higher in Pe. chrysogenum-exposed mosquitoes (P = 0.0001) than in non-exposed controls (N = 25 for each). Error bars represent the standard error of the mean. ****P ≤ 0.0001; two-tailed Mann-Whitney test. (D) Pe. chrysogenum does not produce anti-bacterial products. Image shows four mosquito-isolated bacteria plates: (a) S. marcences, (b) E. hormaechei, (c) B. subtilis, and (d) S. capprae grown with a disk soaked in a fungus culture filtrate-laced sucrose solution (left disc) or a fungus culture filtrate-laced water solution (top disc), as compared to an antibiotic-soaked disc (right disc).