Fig. 3.

Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis of gene expression in rosette leaf tissue of 6-wk-old Arabidopsis seedlings grown in vermiculite potting medium and fertilized with 1/2 × Murashige and Skoog (MS) medium containing 3 mm nitrogen, 0.4 mm nitrogen, no nitrogen (−N) or 1 mm uracil (Ura) as sole nitrogen source. PYD1–3, catabolic pathway; BAT, β-alanine aminotransferase; AtUPS1 and AtUPS2, uracil transporters; AtENT1, uridine transporter; ACT2, constitutively expressed reference gene. Expression values for each transcript, relative to seedlings grown in 3 mm nitrogen and normalized on the basis of ACT2expression, are indicated below each band. ND, not detectable.