Fig. 1
Resistance to M. oryzae infection in rice plants grown under high Fe supply. A Experimental design used for iron treatment and infection with M. oryzae (5 × 105 spores/ml). Rice plants were grown in soil for 16 days under sufficient Fe supply (50 µM Fe, Control plants) and allowed to continue growth under sufficient conditions (Ctrl) or high Fe conditions (1 mM Fe; High Fe) for 5 days more (left panel). Then, the rice plants were inoculated or not with M. oryzae spores and assayed for blast resistance. B Appearance of rice plants that have been treated with high Fe for 5 days. C Shoot and root fresh weight (FW, left and middle panels), and chlorophyll content (right panel) of plants treated with high Fe for 5 days. Differences were not statistically significant. D Total Fe content estimated by the ferrozine colorimetric method in roots, stems and leaves of Control and High Fe-treated plants (5 days of treatment). Data are mean ± SEM (n = 10). Asterisks indicate statistical significance calculated by t-test (*, P < 0.05; **, P < 0.01). E Resistance to M. oryzae in Fe-treated rice plants. Control and High Fe-treated rice plants were inoculated with a conidial suspension of M. oryzae spores (5 × 105 spores/ml), or mock-inoculated. Left panel, Disease symptoms in youngest developed leaves (3rd leaf) at 7 days post-inoculation (dpi) are shown. Results from one representative experiment of four independent experiments are presented. Middle panel, percentage of diseased area at 7 dpi (n = 10). Right panel, fungal biomass was quantified by qPCR using specific primers of the M. oryzae 28S ribosomal gene relative to the rice Ubiquitin 1 gene (Os06g46770) at 7 dpi, (−, mock-inoculated; +, M. oryzae-inoculated). Data are mean ± SEM (n = 10). Asterisks indicate statistically significant differences calculated by t-test (***, P < 0.001)