Biofilm formation of
ExpR defective strains Rm1021 and GR4. A) Confocal images showing the xy and xz planes of biofilm development on chambered cover glass slides at 3 and 10 dpi. A thick, white bar placed next to the corresponding xz plane represents the thickness of each biofilm. Bars, 15 μm. B) Confocal images of alfalfa roots inoculated with GFP-labelled Rm1021 and GR4 strains at 3 dpi. Bars, 70 μm. C) Colony forming unit (CFU) counts recovered from alfalfa roots. Data are expressed per gram of root fresh weight (RFW). Error bars indicate the standard error from the mean. According to the Games-Howell test (P ≤ 0.05), values followed by the same letter do not differ significantly.