Figure 3. fadH expression depends on fruit ripeness and a specific metabolite.

(A) To test regulation of fadH inside fruits of tomatoes and peppers, fadH+ fadH::tnpR res1-tet-res1 reporter was seeded onto shallow wounds in mature and immature fruits of tomatoes and peppers. Activity of the reporter was scored as the loss of the tetracycline marker in the recovered bacteria (‘resolution’). Averages of at least two biological and three technical replications are shown, error bars are standard errors. Fruits of each cultivar at different maturity stages were collected from the same plant. In LB broth, resolution of the fadH RIVET reporter was 0%. (B) To test which metabolite from red or green tomatoes affects the fadH RIVET reporter, resolution of the reporter was measured in soft M9 agar (0.3%) supplemented with the metabolites present in tomato fruits. An upward white arrow at the bottom of each bar indicates that the metabolite increases as tomato matures, a downward arrow indicates that the metabolite decreases with the maturity of the fruit [11]. Glycerol is present at the same amounts in red and green fruit [11], and therefore is not marked with an arrow. The control sample contained no carbon sources. The experiment was repeated twice, with two technical replications. Data from the second experiment are shown, error bars are standard errors.