Figure 2

Expression of auxin carrier genes in Medicago truncatula roots. Expression levels of auxin efflux (PIN1 and PIN2) and influx (LAX1, LAX2 and LAX3) carrier genes were evaluated by quantitative RT-PCR (QRT-PCR). The expression levels were normalized using actin as the endogenous control gene. The QRT-PCR analysis was performed using a ABI Prism 7000 Sequence Detection System. Relative transcript level is the ratio between the expression levels in roots of plant nodulated by the IAA strain and roots of plant nodulated by the control strain. Relative transcript levels were calculated according to manufacturer's recommendations, using the formula 2^{-(ΔCtiaa-ΔCtc)}, where ΔCtiaa and ΔCtc is the difference between the threshold cycle of the gene tested and the threshold cycle of actin in IAA and control samples, respectively. The significance of the differences between control and IAA expression levels was evaluated using a Student's t test (n = 3). Mean values ± SE are reported. *, P < 0.05. Control: plants nodulated by the control strain. IAA: plants nodulated by the IAA strain.