Fig. 3

MAPK pathway genes involved in regulation of AMP expression. a Interaction network predicted by WormNet for 33 MAPK pathway-related Nipi genes (Additional file 7: Table S6). The genes ego-2, tag-214, vhp-1, and wnk-1 are not connected to any other of the genes; Y73B3A.18 is not included in the WormNet set of genes. These five genes are not shown here. The remaining 28 genes are connected by 77 edges. As for all large-scale data mining, there are obvious omissions, due to incomplete coverage in databases. One example is nsy-1 that encodes a MAP3K [122] but does not appear here. b Knocking down vhp-1 by RNAi provokes a marked reduction of nlp-29p::gfp reporter gene expression in IG274 worms carrying the frIs7 transgene infected by D. coniospora. The graph shows the quantification of fluorescence of worms treated with control (CT: K04G11.4; blue; n = 296) or vhp-1 (red; n = 258) RNAi. The green fluorescence and length are plotted in arbitrary, but constant units. c–g A cell-non-autonomous regulatory role for vhp-1. Whereas following systemic knock-down of sta-1 (c) or vhp-1 (d), there was no detectable expression of the nlp-29p::gfp reporter gene in IG274 worms carrying the frIs7 transgene in the absence of infection, knocking-down vhp-1 (f) but not sta-1 (e) specifically in the epidermis in strain IG1502 led to ectopic expression of GFP in the nematode intestine. This expression was most pronounced in the posterior intestinal cells (g). The red fluorescence in the pharynx in (e–g) reflects the presence of an additional transgenic marker. Worms were observed at the L4 stage in all cases. Green and red fluorescence are visualized simultaneously with a long pass GFP filter. Scale bar: 50 μm