Magnaporthe oryzae Glycine-Rich Secretion Protein, Rbf1 Critically Participates in Pathogenicity through the Focal Formation of the Biotrophic Interfacial Complex
(A) Quantitative RT-PCR analysis of RBF1 and PWL2 expression in conidia and inoculated rice leaf blades. The vertical axis indicates the amount of transcripts relative to that from the M. oryzae actin gene (MoACT1). Data are represented as mean values ± standard error (SE) (n = 3 plants). dpi, days post inoculation. (B) The dynamic expression of RBF1. RBF1 expression during the infection process in the rice leaf sheath epidermis was monitored by a long-term time-lapse imaging method using a fungal line transformed with RBF1p::GFP. After appressoria formation, GFP signals were captured at 20-min intervals. The z-series of optical sections corresponding to the outer half of the inner epidermal cells were stacked to generate maximum-intensity projection images. Images displayed were selected from S1 Movie. White and blue arrows indicate the induction of GFP expression in the appressorium and the invasive hyphae, respectively. Red arrows indicate the re-induction of the GFP expression in the hyphal cell that was about to invade the neighboring cell. hpi, hours post inoculation. Bar = 20 μm. (C) Confocal images of M. oryzae transformants introduced with RBF1p::GFP, PWL2p::GFP, or ChBD8p::GFP growing in living rice leaf sheaths (upper) and dead rice leaf sheaths (lower) at 24 hpi. GFP images were merged with differential interference contrast images. Asterisks indicate appressoria. Bar = 20 μm. (D) Quantitative RT-PCR analysis of RBF1 expression in the inoculated living leaf blades of rice and wheat, and dead rice leaf blades at 24 hpi. The vertical axis indicates the amount of transcripts relative to that from the M. oryzae actin gene (MoACT1). Data are represented as mean values ± SE (n = 4 plants).