Responses of <i>C</i>. <i>elegans</i> strains with transcriptional reporters <i>C17H1</i>.<i>6p</i>::<i>GFP</i> and <i>F26F2</i>.<i>1p</i>::<i>GFP</i> to exposure by different microsporidia.

<p>Strains ERT54 carrying <i>C17H1</i>.<i>6p</i>::<i>GFP</i> (<b>A</b>) and ERT72 carrying <i>F26F2</i>.<i>1p</i>::<i>GFP</i> (<b>B</b>) were analyzed for GFP induction at different time points after infection with different microsporidia and the proportion of animals with GFP induction is shown. GFP was reproducibly induced in ERT54 and ERT72 upon infection with <i>N</i>. <i>parisii</i>, <i>N</i>. <i>major</i> and <i>N</i>. <i>homosporus</i>, while GFP signal was rarely observed in ERT54 and ERT72 inoculated with <i>N</i>. <i>ausubeli</i> or <i>E</i>. <i>longa</i> or the negative control. <i>N</i>. <i>ausubeli</i> did infect the <i>C</i>. <i>elegans</i> reporter strains, as monitored by DIC as in <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1006093#ppat.1006093.t005" target="_blank">Table 5</a>. <b>C</b>. Transcript levels for three genes were measured after 4 hours of infection of N2 <i>C</i>. <i>elegans</i> by <i>N</i>. <i>parisii</i> (ERTm1) and <i>N</i>. <i>ausubeli</i> (ERTm2). The fold increase in transcript level was measured relative to uninfected N2 levels. Infection dose was normalized between <i>Nematocida</i> by successful invasion events counted as intracellular sporoplasms at 4 hpi. To independently compare the microsporidian doses in parallel to the transcript quantification, we also measure the levels of <i>Nematocida</i> SSU rRNA after 4 hours of infection of <i>C</i>. <i>elegans</i> in the same experiment: we found that the rRNA level measured after infection with ERTm2 was 1.25-fold higher than that with ERTm1.