Expression of CytC toxin in aphid tissues.

<p>Immunostaining with anti CytC antibodies (except 3C, left) of aphids infected with the wild type <i>D. dadantii</i> strain. Anti CytC antibodies were detected with anti IgG labeled with Alexa fluor 488 (green labeling) and DNA was stained with DAPI (blue labeling). <b>3A to 3B</b>: early infection stage: day 1 of infection. In most samples, no expression of the toxin was detected (3A) although bacterial presence was readily observed in the same sample, for example in the gut lumen (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0030702#pone-0030702-g002" target="_blank">Fig. 2</a>); in some individual insects, toxin expression was detected in the gut lumen (3B). <b>3C to 3E</b>: Primary infection stage: day 2 post infection; 3C, left and right: typical staining difference (in the same aphid) between bacterial detection at many locations, including the fat body (anti-KdgM antibody, 3C left) and toxin expression detection, restricted to the digestive tract (anti-CytC antibody, 3C right); In some instances, toxin expression was also detected in clustered areas of the fat body, in addition to typical gut lumen localization (gl, fb, 3D–E); <b>2F</b>: late infection stage, day 4 post-infection. Toxin detected as a marked stain only in the gut lumen (2F). Abbreviations as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0030702#pone-0030702-g002" target="_blank">Figure 2</a>, plus: oe: oenocytes.