Figure 5. Expression of P, N, K or Fe responsive genes to different nutrient stresses.

14-day old soybean seedlings were treated with N (−N), K (−K) and Fe (−Fe) deficiencies (see Experimental procedures for details). Seedlings grown under normal solution were used as controls (CK, added 500 µM P as KH₂PO₄). The expression levels in shoots and roots were analyzed by quantitative real-time PCR. Soybean gene PLDZ (Glyma20g38200) was used as low P responsive gene (A), NiR (Glyma02g14910) for low N treatment (B), HAK (Glyma3g42480) for low potassium treatment (C) and IRT (Glyma07g34930) for low Fe treatment (D), respectively. Each bar was the mean of three biological replications with standard error.