Figure 3.

Relative transcript levels of polyamine biosynthetic genes encoding Arg decarboxylase (ADC1, ADC2), agmatine iminohydrolase (AIH), N-carbamoylputrescine amidohydrolase (CPA), spermidine synthase (SPDS1, SPDS2), spermine synthase (SPMS, ACL5), and S-adenosyl-Met decarboxylase (SAMDC1, SAMDC2) in noninfected (control) and infected roots of the susceptible accession Col-0 (A) and the partially resistant accession Bur-0 (B) at 14 and 21 dpi. Values were obtained by real-time quantitative RT-PCR and are normalized to the host Actin8 gene. Samples of control and infected roots were analyzed in duplicate in four independent experiments. Significant differences from controls are shown at *, P < 0.05; **, P < 0.01; and ***, P < 0.001.