Figure 4

Pathogen inoculation test of transgenic A. thaliana expressing OsHIR1. (a) Disease symptoms after pathogen inoculation. Six-week-old seedlings of the untransformed wild type (Col-0), the empty vector-transformed control (Col-0/V7), and the OsLRR1 (Col-0/OsLRR1) and OsHIR1 transgenic lines (Col-0/OsHIR1) were challenged with Pst DC3000. The symptoms were recorded 5 days after inoculation. (b) Pathogen titers 5 days after pathogen inoculation. Rosette leaves were collected from inoculated plants for pathogen titer determination. Statistical analysis using ANOVA followed by Fisher's LSD Test (p < 0.05) reveals 3 groups: ¹, the untransformed wild type and the vector-only control; ², OsLRR1 transgenic plants; and ³, OsHIR1 transgenic plants. The error bars indicate standard errors (N = 3). (c) and (d) Expression of defense marker genes without (mock) or with Pst DC3000 inoculation. Real-time RT-PCR was performed using reverse-transcribed RNA samples. Relative expression levels of PR1 and PR2 in all plants were compared to the mock-inoculated untransformed wild type parent (Col-0; expression level set to 1). Both the expressions of PR1 and PR2 can be categorized into different groups using ANOVA followed by Fisher's LSD Test (p < 0.05). In (d), the gene expression in mock-treated Col-0 was used just to set the reference for gene expression and was not included in the statistical analysis. The error bars indicate standard errors (N = 3). Three independent OsHIR1 transgenic lines (Col-0/HIR1-1, Col-0/HIR1-2, and Col-0/HIR1-3) were used for quantitative studies in (b), (c), and (d).