Fig. 4

Tissue-specific transcription profiles of chosen genes involved in metal homeostasis differentially expressed in epidermis + cortex (EC) and stele (S) of roots of 24-day-old AtHMA4-expressing plants (lines 4 and 15) and in the wild-type (WT). Normalized fold gene expression in epidermis + cortex (EC) and stele (S) from roots of plants grown in the presence of 5 μM Zn for 2 weeks (a; d); under control conditions (b; e) and in the presence of 1 μM Cd for 11 days (c; f). In the EC from roots of transgenic line 15, the transcription levels of the studied genes were hardly detectable (values were as follows: IRT1 = 0; NRAMP1 = 0; NRAMP2 = 0; NRAMP3 = 0; Chln = 0.005873; FER = 0.0067678; bZIP44 = 0). LeIRT1 is not expressed in the S. Values correspond to means ± SD (n = 3); those significantly different from the WT (Student’s t-test) are indicated by an asterisk (P ≤ 0.05)