Figure 5: PsIsc1 and VdIsc1 suppress disease resistance.
(a) Western blotting of the indicated transiently expressed proteins in N. benthamiana using anti-GFP antibodies. (b) Phenotypes of leaves transiently expressing the indicated genes inoculated with P. capsici zoospores. Photos were taken at 48 hpi. (c) Lesion diameters of infected regions at 48 hpi, averaged from at least 30 inoculated sites. (d) Free SA (left) and SAG (right) levels (12 hpi) in leaves transiently expressing the indicated genes. (e) Relative levels of PR1 gene transcripts at 12 hpi in infected leaves transiently expressing the indicated genes. (f) Isochorismatase activity by measuring the absorbance at 340 nm. Bacterial EntB and VibB produced by E. coli were used as positive controls. An identical quantity of the tested proteins was purified from plant tissues. VibA generates NADH from DDHB and NAD+ when active ISC was present (producing DDHB from isochorismate); the absorbance of NADH at A340 nm at the indicated time points (seconds) was recorded. (g) Relative DDHB concentrations in plant tissues expressing the indicated genes. The relative DDHB concentration of each tested sample was calculated based on A340 absorbance and the DDHB concentration in GFP-expressing leaves was normalized to 1.0. In a, c–e and g, from left to right: GFP, VdIsc1, PsIsc1, VdIsc1A3 and PsIsc1A3. **P<0.01 (Dunnett’s test).
