The fluorescence GFP and 535 nm for propidium iodide; GFP emission was captured and t 15 through GFP filter; propidium iodide emission was detected in another channel using a 520 t 15 nm bandpass. Image acquisition was performed at a reso lution of 512 x 512 pixels and a rate of 20 us pixel-1 The FLUoVIEW 1.5 software (Olympus) was used con trol the microscope and export images. To examine the bacterial colonization in cortical cells, the nodules or nod ule primordia were sliced longitudinally to 100-300 um before microscopic analysis