TABLE 3.
Influence of P. putida strains differing in pyoverdine production on population size of P. putida N1R Pvd− (pvd-inaZ) in the rhizosphere of cucumber
| Coinoculated straina | Rhizosphere population size of N1R Pvd− (pvd-inaZ)b (log10 [CFU/root system] ± SEM) for coinoculated strain initially at:
|
|||
|---|---|---|---|---|
| ca. 106 CFU/root system
|
ca. 104 CFU/root system
|
|||
| Day 1 | Day 6 | Day 1 | Day 6 | |
| None | 6.42 ± 0.20 | 7.33 ± 0.06 | 5.66 ± 0.21 | 7.04 ± 0.07 |
| WCS358 | 5.09 ± 0.29 | 6.11 ± 0.18 | 5.52 ± 0.25 | 6.80 ± 0.13 |
| WCS358 Pvd− | 5.11 ± 0.06 | 6.19 ± 0.11 | 5.57 ± 0.25 | 6.88 ± 0.07 |
| N1R | 4.78 ± 0.09 | 5.49 ± 0.09 | 5.86 ± 0.19 | 6.70 ± 0.13 |
Root systems were dipped in aqueous suspensions of N1R Pvd− (pvd-inaZ) alone or in combination with a coinoculated strain (WCS358, WCS358 Pvd−, or N1R) before planting in sterilized soil. Coinoculated strains applied at ca. 106 CFU/root system established rhizosphere populations of 6.5 to 7.0 log10 (CFU/root system) at day 1 and 7.5 to 7.6 log10 (CFU/root system) at day 6. Coinoculated strains applied at ca. 104 CFU/root system established populations of 5.9 to 6.4 log10 (CFU/root system) at day 1 and 6.9 to 7.0 log10 (CFU/root system) at day 6.
Initial populations of N1R Pvd− (pvd-inaZ) were approximately 104 CFU/root system. Mean rhizosphere population sizes were estimated at 1 or 6 days after root systems were inoculated with bacterial strains.