Fig 4. Cd-inducible expression of BrMTs and BrPCSs in B. rapa.

One-month old B. rapa plants were treated with 100 μM CdCl₂ for different times and harvested to analyze the expression levels of B. rapa Cd tolerance genes. qRT-PCRs were performed with cDNA synthesized from the RNA as a template and gene-specific primers (S1 Table). The expression levels of Cd tolerance genes were normalized to the level of actin, and the values indicate the average and standard error (biological replicates: 3). *P < 0.05, **P < 0.01 (Student’s t-test).