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.