Effects of root exudate from S. tuberosum plants on the growth of P. atrosepticum. Graphic representation of bacterial growth curve in a standard growth medium (PGA) or medium supplemented with root exudate (1 mg mL⁻¹). In addition, β-GlcY reagent (5 µg mL⁻¹) was added to the growth medium in order to precipitate AGPs contained in the root exudates. Bars show means ± s.e. of three biological replicates; P< 0·05 is significant.