PMC

Co-localization of PLA₂α-RFP with ST-GFP, a Golgi body marker. Close-to-mature leaves of transgenic Arabidopsis plants expressing both PLA₂α-RFP and ST-GFP were observed with a laser scanning confocal microscope. PLA₂α-RFP signals are mostly overlapped with ST-GFP, a Golgi body marker. ST-GFP (A), PLA₂α-RFP (B), bright field (C), and merged image (D) are presented. Bar = 20 μm.

Translocation of PLA₂α to apoplasts was enhanced by the inoculation of bacteria, Pst-avrRpm1, in pre-mature young leaves. (A–C) Images showing increased fluorescence intensity and vesicle sizes followed by the translocation of PLA₂α to apoplasts at 3 h post-inoculation of Pst-avrRpm1 (C) compared to the no-treatment control (A) and 0.015% Silwet/10 mM MgCl₂-treated mock (B) in pre-mature young leaves where PLA₂α is normally localized primarily in Golgi bodies. Fluorescent (top), bright field (middle), and merged images (bottom) are presented. Bars = 20 μm.

Enhanced translocation of PLA₂α to apoplasts in response to the inoculation of Pst-avrRpm1 in close-to-mature leaves. (A–C) Significant enhancement of PLA₂α translocation to apoplasts was observed at 3 h post-inoculation of Pst-avrRpm1 (C) compared to the no-treatment control (A) and 0.015% Silwet/10 mM MgCl₂-treated mock (B) in close-to-mature leaves where PLA₂α is already detected at a low level in the apoplasts. Fluorescent (top), bright field (middle), and merged images (bottom) are presented. Bars = 20 μm.

Spatial and temporal expression of PLA₂α. Spatiotemporal expression patterns of the PLA₂α gene in transgenic Arabidopsis plants harboring the PLA₂α promoter fused with the GUS gene. Promoter activity was visualized by histochemical GUS staining. (A) Seven-day-old plant. (B) Fourteen-day-old plant. (C) Three-week-old plant. (D) Flower cluster, cauline leaf, and stem of a 5-week-old plant. (E–H) Carpels and developing siliques of a 5-week-old plant. (I) Pedicel of the control transgenic plants harboring the 35S promoter fused with the GUS gene. (J) Root of a 6-week-old plant. Bars = 2 mm.

Subcellular localization of PLA₂α at different leaf ages in PLA₂α-RFP transgenic Arabidopsis plants. (A,B) Epidermal cells in pre-mature leaf tissues (A) and mature leaf tissues (B) from Pro35SPLA₂α-RFP transgenic Arabidopsis plants (4-week-old) were viewed using confocal microscopy. (C) Mature leaf tissues were incubated in 1 N KNO₃ to induce plasmolysis before being viewed with confocal microscopy. The slightly decreased clarity of images in (C) appears to result from the diffusion of PLA₂α-RFP into the expanded apoplasts due to plasmolysis. White arrows in (C) indicate the plasmolyzed plasma membrane, whereas black arrows indicate extracellular spaces. Fluorescent (top), bright field (middle), and merged images (bottom) are presented. Bars = 20 μm.