To determine the ability of N43 to protect roots against R. solani Q1 in vivo, cucumber seeds were treated with the GFP-tagged bacteria prior to exposure to the phytopathogenic fungi. The seeds were prepared as described above and then pre-germinated in the dark on sterile wet filter paper in Petri dishes for 4 days. The pre-germinated seeds were immersed in a suspension of GFP-tagged N43 with a concentration of 108 cells ml−1 and then germinated in water agar plates for 2 days. The plates were then inoculated with R. solani Q1 and incubated at 25 °C in the dark. Four days after inoculation with the pathogen, the rhizosphere of the cucumber seedlings was observed with a fluorescence microscope (OLYMPUS MVX10, Tokyo, Japan). Five replicates were performed for each treatment. In the control treatment, seeds were germinated on water agar plates with R. solani alone.