Fig. 6

The propionate reporter acdh-1^prom::GFP is induced by diet, mitochondrial pathway genes, and vitamin B12 availability. Worms carrying acdh-1^prom::GFP (strain VL749) were grown on soy-based NGM agar with 0 nM or 6.4 nM vitamin B12 supplementation. Worms fed on E. coli strain OP50-1 strongly induce GFP expression (a) that is only partially suppressed by adding B12 (b). Worms fed on strain HT115(DE3) also induce GFP expression (c), but this induction is completely suppressed by the addition of vitamin B12 (d). Worms fed on control RNAi [HT115(DE3) and L4440 empty vector] induce acdh-1^prom::GFP expression (e), but this induction is suppressed by adding vitamin B12 (f). rips-1 RNAi induces acdh-1^prom::GFP (g), and induction is suppressed by B12 supplementation (h); metr-1 RNAi induces acdh-1^prom::GFP (i), and induction is only minimally suppressed by B12 addition (j); mce-1 RNAi induces acdh-1^prom::GFP (k) and is completely suppressed by the addition of B12 (l); mmcm-1 RNAi induces acdh-1^prom::GFP (m), and induction is minimally suppressed by B12 addition (n). RNAi and supplementation of B12 only minimally suppress the induction by gas-1 RNAi (o), cyc-1 RNAi (p), and clk-1 RNAi (q) but fully suppress the kynu-1 RNAi induction of this reporter (r). Scale bars denote 0.5 mm. Quantification of GFP signals for conditions in a–d is depicted in s, for e–n is shown in t, and for o–r is shown in u. In s–u, light blue points with lines denote the mean and SEM. p-values were determined from one-way ANOVA, followed by Tukey’s (s) or Dunnett’s (t–u) tests. NS, not significant, *p < 0.05, ***p < 0.001. For s–u, blue significance marks indicate the comparison of the groups treated with vitamin B12 to unsupplemented control, and black and red significance marks indicate the comparison of the RNAi groups to the control (L4440) RNAi groups under no supplement or vitamin B12-supplemented conditions, respectively