TABLE 3.
Symbiotic phenotypes of regR and regS mutants compared to those of the wild type and the nifA mutant A9
| Strain | Relevant genotype | Characteristics (mean ± SE)a
|
||
|---|---|---|---|---|
| Nodule no. | Dry wt/nodule (mg) | Fix activity (% of wild type) | ||
| 110spc4 | Wild type | 31 ± 1 | 1.3 ± 0.06 | 100 ± 5 |
| A9 | nifAb | 59 | 0.3 | 0 |
| 2408 | regS | 36 ± 3 | 0.8 ± 0.05 | 69 ± 12 |
| 2409 | regS | 32 ± 3 | 1.0 ± 0.09 | 109 ± 8 |
| 2426 | regR | 28 ± 2 | 0.9 ± 0.05 | 2.3 ± 0.7 |
| 2427 | regR | 33 ± 2 | 0.8 ± 0.05 | 1.8 ± 0.4 |
a
Values are the means ± standard errors of at least 10 individual plants. Fixation (Fix) activity was measured as the amount of C2H2 reduced per minute per milligram of nodule weight (dry weight).
b
Values shown for the nifA mutant are taken from Fischer et al. (17) for comparison. The assay conditions were identical to those described here.