M. oryzae materials and inoculation assay
The M. oryzae isolate GDYJ7 harboring AvrPik-E was used in this study. Spores were produced by growing the hypha in a complete medium with a 12-h/12-h light/dark cycle at 28°C for 10-14 days. Spray inoculation was performed as previously reported (Bonman, 1986) with modification to evaluate gene expression levels. Spores were collected with 0.02% Tween-20, and spore concentration was adjusted to 5×105 spores/mL. The spore suspension was sprayed onto the surface of two-week-old rice seedling leaves evenly until visible droplets appeared with a spray gun. Samples were collected in 0, 6, 12, 24, 36, 48, 60, and 72 hpi after incubation in the dark for 12 h for quantitative real-time PCR (qRT-PCR). For phenotyping, leaves of 6- to 8-week-old seedlings were punch inoculated as described(Park et al. , 2012). Disease symptom was observed at 7 dpi. The lesion length was calculated using the software ImageJ. The sporulation rate on lesions was determined as described(Park et al. , 2012). Leaf sheath inoculation was performed as described(Koga et al. , 2004) with modification. In brief, the leaf sheaths of 2-week-old seedlings were carefully peeled. The spore suspension was adjusted to 5×105 spores/mL and was injected with a syringe onto the inner surface of leaf sheaths. The seedlings were laid on a 20 cm plate with water and were grown with a 12-h/12-h light/dark cycle at 28°C for 7 days.