Figure 4: Brefeldin A blocks secretion of apoplastic but not of cytoplasmic effectors. | Nature Communications

Figure 4: Brefeldin A blocks secretion of apoplastic but not of cytoplasmic effectors.

From: Two distinct secretion systems facilitate tissue invasion by the rice blast fungus Magnaporthe oryzae

Figure 4

(a–c) Images left to right: either merged bright-field, mCherry and GFP or merged mCherry and GFP; mCherry alone; and GFP alone. (a) After secretion, cytoplasmic effector Pwl2:mCherry:NLS (red) shows preferential BIC localization (arrow) and translocation into the rice cell, where it accumulates in the rice nucleus (*). Bas4:GFP shows apoplastic localization outlining the IH. (b) In the presence of BFA, Pwl2:mCherry:NLS remains BIC-localized (arrow), but Bas4:GFP (green) is retained in the fungal ER, imaged with the same transformant in (a) 10 h after exposure to BFA. (c) Cytoplasmic effectors Bas1:mRFP (red, middle) and AVR-Pita:GFP (green, right) still co-localized in the BIC (arrow) after 5 h exposure to BFA. (d) Fluorescence recovery after photobleaching (FRAP) demonstrates continuous secretion of Pwl2:GFP into the BIC in the presence of BFA. Rice tissue infected by a fungal strain expressing Pwl2:GFP and Bas4:mRFP was incubated in BFA for 3 h before photobleaching of Pwl2:GFP in the BIC. Secretion of Bas4:mRFP had been blocked at this point. FRAP results were identical in the presence or absence of BFA (P=0.019). Bars show mean fluorescence intensity recovery after bleaching (mean±s.d., four FRAP experiments). Images left to right before photobleaching: merged bright-field and GFP; GFP alone; and mRFP alone. Images left to right after photobleaching and recovery: merged bright-field and GFP; and GFP alone. Scale bars, 10 μm.

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