41 PA14 genes required for virulence in a C. elegans infection based killing model.

The ratio of nematode survival on mutant PA14 to that on wild-type PA14 (mutant LT50/WT LT50) is presented for 41 mutants identified after three rounds of screening as well as for the known virulence-attenuated mutants, lasR and pilA. The time to 50% death (LT50) was calculated using a non-linear regression based on the Hill equation (Prism 5.0). 100–150 animals were tested in each experiment. Error bars represent the SEM of the ratios derived from at least two different experiments (lack of error bars indicates that the mutants for known virulence factors gacA, ptsP and vfr were tested only once). Red bars depict the ratio of the LT50 of lasR or pilA to WT PA14. The lasR and pilA mutants were generated previously (see Materials and Methods); there are no alleles of lasR or pilA in the NR library. The number of alleles tested with an avirulent phenotype is indicated by a number below the graph: 1 indicates that a single allele was tested but that there exist multiple alleles in the master transposon library, S indicates only a single allele was available in the library. Genes that are predicted to be in operons are indicated (Y = yes, N = no). Genes in a single operon are represented in the same color and an underline designates that other genes within the same operon were tested for their role in virulence.