Figure 7.

GC activity of OsWAKL21.2 is required for the induction of immune responses in Arabidopsis but not in rice. A, Quantification of callose deposition in leaves of two different Arabidopsis transgenic lines (lines 3 and 6) expressing GC-deficient OsWAKL21.2-gcd that were treated with either 20 µm Est (inducer) or 0.1% (v/v) DMSO (control). Each bar represents the average, and error bars represent se of three leaves in an experiment. B, Effects of heterologous expression of OsWAKL21.2-gcd on the growth of Pst DC3000 after subsequent infection. Leaves of wild-type (wt) OsWAKL21.2 and two different OsWAKL21.2-gcd Arabidopsis transgenic lines (lines 3 and 6) were infiltrated with either 20 µm Est (inducer) or 0.1% (v/v) DMSO (control) and were subsequently inoculated with Pst DC3000 12 h post infiltration. Each bar represents the average, and error bars represent se of five leaves in each sample. CFU, Colony-forming units. C, Effects of heterologous expression of OsWAKL21.2-gcd on the expression of key defense-related OsWAKL21.2-induced genes in transgenic Arabidopsis lines. Expression in 0.1% (v/v) DMSO-treated leaves was considered as 1, and relative expression in 20 µm Est-treated leaves was calculated with respect to it. Each bar represents the average FC, and error bars indicate se of three independent experiments (n = 3 in each experiment). D, Quantification of callose deposition after transient overexpression of either wild-type OsWAKL21.2 or OsWAKL21.2-gcd in rice leaves. Each bar represents the average, and error bars represent se of at least 12 leaves per treatment in an experiment. E, Lesion lengths after 10 d of Xoo pin-prick inoculation when OsWAKL21.2 or OsWAKL21.2-gcd was transiently overexpressed prior to infection by Xoo. Each bar represents the average, and error bars represent se of lesion length in 20 to 30 leaves in an experiment. F, Relative expression of key defense-related genes after transient overexpression of either OsWAKL21.2 or OsWAKL21.2-gcd in rice leaves. For each gene, the transcript level under uninduced conditions (treatment with A. tumefaciens carrying OsWAKL21.2 or OsWAKL21.2-gcd with 0.1% [v/v] DMSO) was considered as 1 and was compared with that under the induced conditions (treatment with A. tumefaciens carrying OsWAKL21.2 or OsWAKL21.2-gcd with 20 µm Est). Each bar represents the average FC, and error bars indicate se of three independent experiments (n = 12 in each experiment). In C and F, AtACTIN2 and OsACTIN1 were used, respectively, as internal controls for RT-qPCR. The relative FC was calculated by using the 2^−∆∆Ct method. Similar results were obtained in three different experiments in A, B, D, and E. In A, B, D, and E, asterisks represent significant differences when calculated using one-way ANOVA followed by the Tukey-Kramer multiple comparison test with P < 0.05. In C and F, asterisks represent significant differences in FC using Student’s t test with P < 0.05. n.s. indicates no significant difference.