Figure 4.

OE of AtMYB2 induces miR399f expression and Pi accumulation. Wild type (WT) and three independent lines of CaMV35S:AtMYB2 (AtMYB2 OE) were grown in MS medium. Ten-day-old seedlings were analyzed. A and B, Expression levels of AtMYB2 (A) and UBC24 (B), normalized to the level of TUBULIN2. Transcript levels were analyzed in total RNA extracted from the seedlings by qRT-PCR. Bars represent means ± sd for three biological replicates with two technical replicates each. C, Northern-blot analysis of miR399f expression in total RNA. Ethidium bromide-stained 5S rRNA bands are shown as loading controls. D, Inorganic Pi concentrations were measured in the roots and shoots. Bars represent means ± sd for two biological replicates. Asterisks represent significant differences from the wild type (P ≤ 0.05 from a Student’s t test). F.W., Fresh weight.