TABLE 5.
Effects of exogenous disaccharides on the growth of salt-stressed cultures of several rhizobiaa
| Rhizobial strain | Growth parameters of the indicated strains in minimal mediumb
|
|||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Without NaCl
|
With NaClc
|
|||||||||||
| Without disaccharide
|
With a disaccharided
|
|||||||||||
| Sucrose
|
Trehalose
|
Maltose
|
Cellobiose
|
|||||||||
| DT (h) | ODmax | DT (h) | ODmax | DT (h) | ODmax | DT (h) | ODmax | DT (h) | ODmax | DT (h) | ODmax | |
| S. meliloti | ||||||||||||
| 102F34 | 4 | 3.1 | 18 | 0.9 | 8 | 2.9 | 7 | 3.0 | 6 | 2.8 | 7 | 2.9 |
| SU47 | 2 | 3.0 | 9 | 1.5 | 3 | 3.1 | 3 | 3.1 | 3 | 3.0 | 3 | 3.1 |
| M5N1 | 7 | 2.7 | 17 | 0.7 | 7 | 3.1 | 7 | 3.1 | 7 | 3.0 | 7 | 3.1 |
| 444 | 4 | 2.5 | 12 | 0.8 | 6 | 2.5 | 6 | 2.5 | 6 | 2.6 | 6 | 2.6 |
| 2009 | 4 | 1.5 | 12 | 0.4 | 6 | 1.4 | 6 | 1.4 | 6 | 1.5 | 6 | 1.6 |
| R. leguminosarum | ||||||||||||
| bv. phaseoli | ||||||||||||
| H132 | 9 | 1.1 | 20 | 0.5 | 11 | 1.1 | 11 | 1.0 | 11 | 1.0 | 11 | 1.0 |
| p15S | 4 | 2.8 | 17 | 1.3 | 8 | 2.8 | 8 | 2.8 | 8 | 2.4 | 8 | 1.9 |
| p12S | 6 | 3.9 | 15 | 1.3 | 7 | 3.2 | 7 | 3.3 | 7 | 3.3 | 7 | 3.1 |
| bv. trifolii | ||||||||||||
| T22 | 4 | 2.1 | 10 | 0.9 | 4 | 1.6 | 4 | 2.2 | 4 | 1.6 | 4 | 1.6 |
| T8S | 5 | 2.6 | 31 | 0.6 | 14 | 2.6 | 14 | 1.7 | 31 | 0.6 | 14 | 1.6 |
| T17S | 4 | 2.5 | 20 | 1.1 | 8 | 1.5 | 8 | 1.6 | 20 | 1.0 | 20 | 1.0 |
a
Cultures were grown in mannitol-aspartate minimal medium.
b
See footnote b in Table 2.
c
NaCl concentrations in the growth medium were 0.5 M for S. meliloti; 0.3, 0.5, and 0.6 M for R. leguminosarum bv. phaseoli strains H132, p12S, and p15S, respectively; and 0.7 M for R. leguminosarum bv. trifolii.
d
Disaccharides provided as putative osmoprotectants were supplied at a concentration of 1 mM.