Nuclear localization of TcNPR1-EGFP in transgenic Arabidopsis plants in response to SA. A. Confocal images of EGFP fluorescence in Arabidopsis leaves of 4-week-old soil-grown plants 24 hrs after H2O (upper images) or 1 mM SA (lower images) treatment. All images were taken at the same magnification and exposure times. Arrows indicate the accumulation of green fluorescence in guard cell nuclei after SA treatment. Scale bar, 10 μm. B. Confocal images of EGFP fluorescence in Arabidopsis roots from 10-day-old seedlings grown on MS (upper images) or MS supplemented with 0.5 mM SA (lower images). All images were captured using the same exposure settings. Arrows indicate the accumulation of EGFP in nuclei of root cells after SA treatment. Scale bar, 30 μm. Samples from transgenic plants generated with pCAMBIA1300 (vector ctrl) was used as negative control and samples from transgenic plants expressing 35S:EGFP served as positive control in A and B.