Figure 4

P. Parasitica appressorium transiently express a RXLR encoding effector during the penetration process. (A and B) Expression pattern of the CL380 RXLR encoding gene using a pCL380::GFP-GUS fusion. (A) Kinetic of early infection steps using a simplified penetration assay based on onion epidermis. GFP fluorescence from a P. parasitica strain carrying the pCL380::GFP-GUS construct was monitored 2 to 30 hours after inoculation of zoospores on onion epidermis. (B) Analysis of the CL380 expression pattern during early A. thaliana infection. A. thaliana plantlets where inoculated with zoospores from a P. parasitica strain carrying the pCL380::GFP-GUS construct and fluorescence was monitored during infection of the first cell (6 hours after inoculation for the presented image) and late biotrophic phase (24 hours after inoculation for the proposed image). Plant cell membranes (red) are visualized with the mCherry plasma membrane marker pm-RB. A representative image for each stage is presented. GFP and mCherry fluorescence was visualized using a confocal laser scanning microscope. Bars: 10 μM; Arrows: appressoria; Stars: Infectious hyphae.