Figure 3. Differential expression of conserved miRNAs in response to N deficiency in shoots (A) and roots (B).

Only miRNA genes with > 2-fold relative change are shown. Selected miRNAs from roots were validated by Real time RT-PCR (C) or small RNA northern blot (D). Maize seedlings were grown hydroponically with full-strength Hoagland's nutrient solution for 2 weeks and then transferred to the N-free or N-sufficient medium for 2 d before total/small RNA was isolated. Real-time RT-PCR quantifications were normalized to the expression of ZmGAPC2. The results represent SD of three replicates. A 40 µg small RNA was loaded per lane and hybridized with corresponding ³²P-labeled probes. 5s/tRNA is shown as a loading control.