Table 2.
Physico-chemical and growth-promoting characteristics of maize seed-borne endophytic bacteria.
| Characteristics | P. ananatis S6 | P. ananatis S7 | P. anantis S8 |
|---|---|---|---|
| PHENOTYPIC CHARACTERIZATION | |||
| Colony color | Yellow | Yellow | Yellow |
| Colony morphology | Round | Round | Round |
| BACTERIAL GROWTH CONDITIONS | |||
| Temperature | |||
| 4°C | + | + | + |
| 42°C | − | − | − |
| NaCl | |||
| 2% | + | + | + |
| 6% | + | + | + |
| pH: | |||
| 5 | + | + | + |
| 12 | + | + | + |
| MOTILITY/CHEMOTAXISa | |||
| Swimming | + | + | + |
| Swarming | ++ | + | + |
| Twitching | + | + | + |
| Biofilm formation | |||
| OD (600 nm) | 0.95 ± 0.08 | 0.89 ± 0.07 | 0.92 ± 0.06 |
| Biofilm (595 nm) | 0.08 ± 0.01 | 0.07 ± 0.01 | 0.06 ± 0.01 |
| Aggregate stability (%) | 32.61 ± 2.13 | 28.61 ± 1.93 | 30.61 ± 2.01 |
| BIOCHEMICAL CHARACTERIZATIONb | |||
| Catalase | + | + | + |
| Oxidase | − | − | − |
| Casein | − | − | − |
| Gelatin | 3.5 ± 0.15 | 2.9 ± 0.10 | 3.2 ± 0.12 |
| Methanol | − | − | − |
| Ethanol | − | − | − |
| GROWTH PROMOTING CHARACTERIZATIONa | |||
| ACC-deaminase activity | + | + | + |
| Auxin production (IAA equivalent μg mL−1) | |||
| Without L-TRP | 0.87 ± 0.55 | 0.68 ± 0.52 | 0.78 ± 0.54 |
| With L-TRP | 32.67 ± 3.17 | 27.45 ± 2.89 | 30.89 ± 3.17 |
| P-solubilization (Inorganic/organic P) | |||
| Ca3(PO4)2 | 1.6 ± 0.10 | 1.2 ± 0.14 | 1.4 ± 0.14 |
| CaHPO4 | 1.5 ± 0.08 | 1.0 ± 0.06 | 1.2 ± 0.08 |
| Ca-Phytate | 2.5 ± 0.11 | 2.0 ± 0.10 | 2.3 ± 0.11 |
| Na-Phytate | 1.4 ± 0.06 | 0.9 ± 0.02 | 1.0 ± 0.06 |
| Exopolysaccharide | − | − | − |
| HCN production | − | − | − |
| NH3 production | + | + | + |
| Siderophore | − | − | − |
| AHL | + | + | + |
| PHB | + | + | + |
| ENZYME HYDROLYZING ACTIVITYa (COLON DIAMETER CM) | |||
| Amylase | − | − | − |
| Cellulase | − | − | − |
| Chitinase | − | − | − |
| Lipase | 2.2 ± 0.09 | 1.8 ± 0.08 | 2.0 ± 0.09 |
| Pectinase | 1.5 ± 0.11 | 1.2 ± 0.04 | 1.0 ± 0.05 |
| Phosphatase | 1.6 ± 0.08 | 1.3 ± 0.07 | 1.0 ± 0.08 |
| Protease | − | − | − |
| Xylanase | 1.3 ± 0.09 | 0.8 ± 0.02 | 1.0 ± 0.06 |
| ANTIBIOTIC RESISTANCE (μg mL−1) | |||
| Ampicillin | − | − | − |
| Gentamycin | − | − | − |
| Kanamycin | − | − | − |
| Chloramphenicol | − | − | − |
| Rifampicin | − | − | − |
| Spectinomycin | − | − | − |
| Streptomycin | − | − | − |
| Tetracycline | − | − | − |
| ANTI-FUNGAL ACTIVITY (COLON DIAMETER cm) | |||
| F. caulimons | 2.0 ± 0.05 | − | − |
| F. graminarium | 1.2 ± 0.04 | − | 1.0 ± 0.04 |
| F. oxysporum | 1.0 ± 0.03 | 1.0 ± 0.03 | 1.0 ± 0.03 |
| F. solani | − | − | − |
| R. solani | 1.8 ± 0.07 | − | 1.5 ± 0.06 |
| T. basicola | 1.2 ± 0.05 | 1.2 ± 0.05 | − |
| ANTI-OOMYCETE ACTIVITY | |||
| P. infestans | 3.4 ± 0.11 | − | − |
| P. citricola | 3.5 ± 0.09 | 3.0 ± 0.09 | 3.0 ± 0.12 |
| P. cominarum | 2.8 ± 0.08 | − | − |
a
Results in characterization table are of 4–6 replicates.
b
−, absent; +, present.