Fig. 2.

Symbiotic phenotypes of S. meliloti 1021Δhfqp#5. Leaves of plants inoculated with S. meliloti strains a, Rm1021pBBR1MCS-5; b, 1021∆hfqp#5; and c, 1021∆hfq pBBR1MCS-5. d, e and f, Corresponding representative nodules. Arrowheads indicate legHb protein produced in nitrogen fixation zone. g, h, and i, Shoot dry mass mean values of 2 independent cultures are given in mg/plant ± SEM. At least 56 plants were used per culture for each independent culture (n = 56). Average values of shoot dry mass for bacteria infected plants that differ significantly from the corresponding value for plants inoculated with water were determined using Student’s t test and indicated as follows: *, P < 0.001; **, P < 0.005