TABLE 3.
Phenotypic effects of sss, ptsP, and orfT mutations in P. fluorescens Q8r1-96
| Strain | Siderophore productiona | Exoprotease production afterb:
|
Motility afterc:
|
MAPG productiond | 2,4-DAPG productiond | Total production of phloroglucinal-related compoundsd | |||
|---|---|---|---|---|---|---|---|---|---|
| 48 h | 72 h | 24 h | 48 h | 72 h | |||||
| Q8r1-96 | 8.5 a | 6.7 a | 9.8 a | 20.2 a | 32.3 a | 38.7 a | 2.1 × 106 a (100) | 9.4 × 106 a (100) | 12.0 × 106 b (100) |
| Q8r1-96sss | 7.4 b | 7.5 b | 11.2 b | 19.2 a | 30.8 a | 36.5 a | 2.8 × 106 a (132) | 12.7 × 106 b (134) | 16.1 × 106 a (133) |
| Q8r1-96ptsP | 11.4 b | 4.5 b | 8.7 b | 17 b | 29.6 b | 35.1 b | 1.1 × 106 be (54) | 5.7 × 106 b (60) | 7.6 × 106 ae (63) |
| Q8r1-96orfT | 8.0 a | 6.8 a | 10.7 a | 17.2 b | 27.8 b | 32.8 b | 2.5 × 106 a (120) | 11.5 × 106 a (122) | 14.6 × 106 a (121) |
Siderophore production was determined by measuring orange halos (in millimeters) after 2 days of growth at 28°C on CAS agar plates. The values are means for four replicate plates. Values followed by the same letter are not significantly different as determined by a two-sample t test in which each mutant was compared separately to the wild type.
Zone of casein digestion on milk agar plates (in millimeters) after 48 and 72 h of bacterial growth. The values are means for three replicate plates. Values followed by the same letter are not significantly different as determined by a two-sample t test in which each mutant was compared separately to the wild type.
Diameter of bacterial spread (in millimeters) on 0.3% LB agar. The values are means for six replicate plates after 24, 48, and 72 h of bacterial growth. Values followed by the same letter are not significantly different as determined by a two-sample t test in which each mutant was compared separately to the wild type.
Production expressed as peak area/optical density. The values are means for five replicate extractions. Values followed by the same letter are not significantly different as determined by a two-sample t test (unless indicated otherwise) in which each mutant was compared separately to the wild type. The values in parentheses are percentages of production relative to production by Q8r1-96, which was set at 100%.
Significance was determined by the Wilcoxon rank sum test (α = 0.05).