FIG 7.

The ΔssuD mutant is defective in symbiosis with cowpea. (A) The WT strain formed effective nodules on cowpea. Bar, 1 mm. Inset, nodule showing leghemoglobin (pink). Bar, 100 μm. (B) The ΔssuD mutant formed ineffective nodules. Bar, 1 mm. Inset, nodule showing lack of leghemoglobin (white). Bar, 100 μm. (C) Shoot dry weight of plants inoculated with the ΔssuD mutant was similar to that of the uninoculated control plant and significantly less than the plants inoculated with WT. The results are means ± SDs from three independent observations with four plants each. Bars with different lowercase letters are significantly different (P < 0.05) from each other.