Figure 3.

SnRK1 regulates gene expression as well as binds directly to specific target genes in response to oxygen deprivation under flooding. A and B, ADH1 (A) and PDC1 (B) expression was induced by submergence. This induction was abolished in the presence of inactive forms of SnRK1s or 90 mm Suc. RNA was extracted from Col as well as transgenic plants expressing wild-type (WT) or inactive forms of SnRK1 under the submergence condition (24 h), and marker gene expression was measured using real-time RT-PCR. All experiments were repeated three times with consistent results. The means of triplicate measurements are shown with se bars. C, Wild-type OsSnRK1-expressing transgenic plants distinctively displayed green shoots, but OsSnRK1_IN-expressing transgenic plants turned albino under a prolonged flooding condition in the dark. D, Transgenic plants expressing inactive forms of SnRK1 resulted in the accelerated loss of chlorophyll during flooding conditions in the dark. Experiments were repeated three times with triplicates and showed consistent results. E and F, SnRK1 associated with ADH1 (E) and PDC1 (F) promoters under flooding. All gene-specific primer sets generated PCR products of expected sizes with Arabidopsis genomic DNA isolated from Col as controls (gels at bottom). Structures of promoters were analyzed and depicted as schematic diagrams. G and H, Chromatin association of SnRK1s at ADH1_6 (G) and PDC1_4 (H) regions was further increased in transgenic plants expressing wild-type OsSnRK1 under flooding. The experiments were repeated twice with consistent results. The means of triplicate measurements are shown with se bars. [See online article for color version of this figure.]