Figure 4.

Relative expression levels by qRT-PCR of the three iron stress-related genes (SlFRO1, SlIRT1, and SlFER) in roots of control tomato plants. The three cDNA pools from roots of three control plants (three biological replicates) were tested in triplicate and normalized using the geometric average of the relative expression of the two reference genes SlTIP4l and SlCAC. Relative expression levels of the three genes were referred to those of a calibrator set to the value of one, which was represented by the gene with the lowest expression (SlFRO1). Statistics are the same as in Figure 2.