Symbiotic phenotype of Sinorhizobium meliloti 1021Δhfq. Top panels show 18-day-old shoots of Medicago truncatula seedlings inoculated with S. meliloti
A, Rm1021; B, 1021Δhfq; and C, 1021Δhfq pHfq. D, E, and F, Representative nodules harvested from the plants in the upper panels. Nodules formed within the susceptible zones (RT1 and RT2) of main roots were harvested 18 days postinoculation. Images are on the same scale, which was assured by placing a ruler in the photographed field (left of panel A) and then cropping segments of the same size using Adobe Photoshop. Scale bar in F = 1 mm.