Fig. 5
From: Synergistic action of the gut microbiota in environmental RNA interference in a leaf beetle
Degradation of dsRNA promotes gut bacterial growth in P. versicolora larvae. a dsGFP incubation with hemolymph or gut fluid of P. versicolora third instar larvae. Samples of 5 μL gut juice or hemolymph (adjusted to 5 μg of total protein) were incubated with 400 ng of dsGFP for the indicated times at 28 °C. G: gut juice sample without dsRNA added; H: hemolymph sample without dsRNA added. b Expression patterns of two putative dsRNase genes in third instar larvae. Each sample comprises five pooled guts or carcasses from dissected larvae. Error bars represent the mean of three independent samples ± SEM. c Relative expression changes of dsRNase1 in larvae fed with dsGFP-painted leaves (8 ng/cm2) at the indicated times compared with untreated control larvae. Gene expression levels were set to 1 in larvae fed with H2O-treated control leaves (ctrl). d dsRNase1 silencing efficiency over time in larvae (n = 5) injected with 40 ng of dsdsRNase. Injection of larvae with the same amount of dsGFP served as control. e dsGFP incubation in gut fluid of P. versicolora larvae with or without suppression of dsRNase1 expression. Samples of 5 μL gut fluid (adjusted to 5 μg of total protein) were incubated with 400 ng of dsGFP for the indicated times at 28 °C. f qRT-PCR analysis of the relative abundance of gut bacteria in P. versicolora second instar larvae fed on young poplar leaves painted with dsdsRNase1 (40 ng/cm2) + dsGFP (8 ng/cm2), or dsGFP (40 ng/cm2) + dsGFP (8 ng/cm2). Guts were sampled at day 4 (n = 7). g Relative expression levels of dsRNase1 in the larvae assayed in (f). h dsRNA degradation products promote the growth of three gut bacterial species. Bacteria were grown for 24 h in either carbon-free or nitrogen-free liquid medium supplemented with 24 nmol/mL of the indicated compounds (dsGFP, ribose, adenine, adenosine, cytidine, uridine, inosine). Glucose (0.4%) and sodium citrate (0.05%) served as carbon source in nitrogen-free media. (NH4)2SO4 (0.4%) served as nitrogen source in carbon-free media. *** P < 0.001, ** P < 0.01, * P < 0.05