RT -PCR analysis of Al-responsive gene expressions in cell suspension. Typical RT -PCR profile of gene expressions in Al-treated cell suspension is shown. Total RNA was isolated from cell suspension and then RT-PCR was performed. Actin was used as an internal control. (A) Suspension-cultured cells of Arabidopsis thaliana with ecotype Columbia backgroud namely wildtype (cell line, Col-0), mutants (cell lines, sid2 and npr1) and transgenic cell lines (cell lines, NahG, overexpressing bacterial SA hydroxylase; NPR-Ox, overexpressing NPR1 gene) were treated with 0.1 mM AlCl3 for 3 h. (B) Cell suspension was treated with 0.1 mM AlCl3 for assessing the rapid and long-lasting gene expression. Upper, treated with 0.1 mM AlCl3 for 0, 1, 5, 15, 30, 60 min. Lower, treated with 0.1 mM AlCl3 for 0, 1, 2, 3, 6, 12, 24 h. (C) Cell suspension were treated with 1 mM DPI and 5,000 units/ml SOD for 5 min before treatment with 0.1 mM AlCl3 for 3 h.