Figure 1.

Effects of molecules released by selected strains of ISR-inducing Pseudomonas spp. bacteria on plant growth and root system architecture of Arabidopsis Col-0 seedlings. A to D, Representative images of seedlings growing on control plates and plates containing WCS417, WCS374, or WCS358 bacteria. Surface-sterilized seeds were sown on 1× Murashige and Skoog agar-solidified medium supplemented with 0.5% Suc. At 4 d post germination, 240 μL of bacterial suspension was spotted on the opposite side of the plate at a 5-cm distance from the root tip. Photographs were taken after 8 d of cocultivation. E, Shoot biomass production measured after 8 d of cocultivation with the indicated bacterial strains. Data represent mean fresh weights ± sd of three groups of seedlings each consisting of 10 excised shoots. Different letters indicate statistically significant differences (Tukey’s HSD test; P < 0.05). The experiment was repeated twice with similar results.