Figure 2.

PKABA1 suppresses the GA₃-induced expression of a low-pI α-amylase gene. (A) Schematic diagram of the effector and reporter constructs used in cobombardment experiments. (B) The effector construct, UBI-PKABA1, was cobombarded into barley half-seeds (with aleurone layers still attached to the starchy endosperm) along with the reporter construct (Amy32b promoter-GUS) and the internal control construct (UBI-luciferase). The amount of reporter and control plasmid DNA was always constant (1.14 μg per shot), whereas that of effector varied with respect to the reporter as shown in the x axis. Transfected half-seeds were incubated for 24 h with (■) or without (●) 1 μM GA₃. GUS activity was normalized in every independent transformation relative to the luciferase activity. Data are means ± SE of four replicates in a typical experiment. The experiment was repeated three times, and similar results were obtained.