Figure 2.

GST Activity Is Required for MKK9-Induced Camalexin Biosynthesis.

Twelve-day-old MKK9^DD seedlings were pretreated with 10 μM 3GA (inhibitor of GST activity) for 72 h before DEX treatment. The camalexin concentration and GST activity in MKK9^DD seedlings in the presence (open circles) or absence (closed circles) of 3GA were measured.

(A) MKK9-induced camalexin biosynthesis was effectively inhibited by 3GA treatment.

(B) MKK9-induced GST activity was effectively inhibited by 3GA treatment. In (A) and (B), data represent the means ± sd of three biological replicates. Asterisks indicate statistically significant differences between MKK9^DD seedlings treated with DEX alone and those treated with DEX plus 3GA. **P < 0.01 (paired sample t test).

(C) Gel regions indicated that the MKK9^DD seedlings accumulated comparable levels of GSTF2 (spots 14 and 22), GSTF6 (spots 18 and 21), and GSTF7 (spots 9 and 11) in the presence or absence of 3GA. Proteins were extracted from the seedlings 8 h after DEX treatment.