Resistance of inx-14 loss-of-function mutants to PA14 infection requires the PMK-1/p38 pathway, but not FOXO/DAF-16 or TGF-β/DBL-1 immune pathways. (A–C) PA14 survival assays of wild-type and inx-14(ag17) mutants fed with vector control, or RNAi against PMK-1/p38 pathway genes nsy-1
(A), sek-1
(B), pmk-1
(C). (D–F) Survival assays of wild-type and inx-14(ag17) mutants fed on vector control or RNAi against IIS/DAF-16 pathway component genes daf-2
(D), age-1
(E), daf-16
(F). (G–I) Survival assays of wild-type and inx-14(ag17) mutants fed on vector control or RNAi targeting DBL-1/TGF-β pathway components sma-3
(G), sma-6
(H), dbl-1
(I). (J) Representative western blots and quantitative analysis of the phosphorylation level of PMK-1/p38 in wild-type animals fed with vector control or inx-14 RNAi prior to PA14 infection for 24 (h) (K) RT-qPCR analyses of the expression levels of six PMK-1/p38-dependent genes in wild- type and inx-14(ag17) mutant animals fed on OP50 or exposed to PA14. The exact P values of statistics for comparison of qRT-PCR between groups are listed in
Supplemental Table S2
. (L–O) Representative images (L, N) and quantification (M, O) of PMK-1/p38 pathway-dependent gene reporters F35E12.5p::GFP (L, M) or K08D8.5p::GFP (N, O) fed on vector control or inx-14 RNAi bacteria prior to OP50 feeding or PA14 exposure. All experiments were repeated at least three times. Column data with plots are presented as mean ± SEM. The number of animals analyzed is indicated. Statistical significance was determined by log-rank test for survival assays, or non-parametric test for (J), or Kruskal–Wallis with Dunn’s multiple comparison test for (K, M, O). *P < 0.05; **P < 0.01; ***P < 0.001; n.s., not significant. Scale bar, 100μm in (L, N).