Figure 4

Evaluation of exogenous application of purified PtDef protein as an analog for cefotaxime in rooting culture medium. (A) Comparisons of the antioxidative activities of transgenic poplars grown in rooting medium with 100 mg/L purified PtDef protein and 200 mg/L cefotaxime. Peroxidase (POD), superoxide dismutase (SOD), malondialdehyde (MDA), and proline (Pro) activity of transgenic poplars grown in rooting medium with 200 mg/L of cefotaxime and 100 mg/L of purified PtDef protein. Three independent experiments were performed. All values are the means ± standard deviation. (B) Transcript levels of reactive oxygen species (ROS)-scavenging enzymes including ascorbate peroxidase (APX), catalase (CAT), glutathione S-transferase (GST), SOD and ROS-producing genes including RbohA and RbohB in leaves of transgenic poplars cultured in rooting culture medium with 100 mg/L of purified PtDef protein and 200 mg/L of cefotaxime, respectively. (C) The expression levels of ROS-scavenging molecules, including APX, CAT, GST, and SOD, and ROS-producing genes, including RbohA and RbohB, in roots of transgenic poplars cultured in rooting culture medium with 100 mg/L purified PtDef protein and 200 mg/L cefotaxime. Data were analyzed using quantitative reverse-transcription PCR and normalized to actin mRNA levels using the 2^−ΔΔCt method. Vertical bars represent the means ± standard deviation (n = 3). Significant differences are denoted by asterisks (*P < 0.05; **P < 0.01).