Table 2.
Features associated with potential plant growth promoting (PGP) activities of bacterial isolates: indole-3-acetic acid (IAA)-like compounds production, siderophores production and phosphate solubilization. The values are means ± standard deviation (SD; n = 3).
| Strain | IAA-like Compounds Production (µg/mL) | Siderophores Production | SI | |||||
|---|---|---|---|---|---|---|---|---|
| Trp+ | Trp- | Sid-CAS | Sid-CAS (psu) | HTS | CTS | |||
| ER1 | C. koreensis | 8.72 ± 0.22 | 1.69 ± 0.04 | +++ | 72.52 ± 0.22 | 1.45 ± 0.41 | 0.58 ± 0.09 | 0.00 |
| ES1 | Rhizobium sp. | 0.75 ± 0.03 | 0.67 ± 0.04 | + | 34.57 ± 0.22 | 2.02 ± 0.07 | 0.01 ± 0.00 | 0.00 |
| ES2 | S. maltophilia | 19.18 ± 0.20 | 4.26 ± 0.15 | - | 6.09 ± 0.08 | 0.38 ± 0.047 | 0.00 | 0.00 |
| ES4 | Brevundimonas sp. | 6.51 ± 0.10 | 0.83 ± 0.03 | + | 25.10 ± 0.06 | 0.68 ± 0.01 | 0.00 | 0.00 |
| ES7 | Brevundimonas sp. | 1.70 ± 0.03 | 0.35 ± 0.04 | ++ | 55.70 ± 0.08 | 0.38 ± 0.03 | 1.93 ± 0.03 | 0.00 |
| ZR1 | N. resinovorum | 0.22 ± 0.03 | 0.17 ± 0.01 | + | 23.69 ± 0.10 | 0.33 ± 0.51 | 0.12 ± 0.01 | 2.82 ± 0.11 |
| ZR3 | D. acidovorans | 2.65 ± 0.13 | 0.94 ± 0.07 | − | 00.00 | 00.00 | 00.00 | 0.00 |
| ZR4 | D. acidovorans | 1.73 ± 0.17 | 0.73 ± 0.03 | ++ | 60.26 ± 0.15 | 2.04 ± 0.17 | 0.19 ± 0.02 | 0.00 |
| ZR5 | Stenotrophomonas sp. | 8.27 ± 0.15 | 0.78 ± 0.02 | − | 0.00 | 0.00 | 0.00 | 0.00 |
| ZS2 | D. acidovorans | 10.43 ± 0.31 | 0.77 ± 0.04 | +++ | 81.62 ± 0.23 | 0.51 ± 0.20 | 0.49 ± 0.05 | 0.00 |
| ZS5 | D. acidovorans | 5.58 ± 0.17 | 0.92 ± 0.02 | +++ | 77.92 ± 0.07 | 1.02 ± 0.32 | 0.28 ± 0.02 | 0.00 |
| ZS6 | Delftia sp. | 2.66 ± 0.27 | 1.07 ± 0.05 | - | 36.84 ± 0.13 | 0.21 ± 0.04 | 0.00 | 4.1 ± 0.11 |
| SR1 | Delftia sp. | 14.53 ± 0.31 | 1.39 ± 0.05 | ++ | 69.87 ± 0.10 | 0.000 | 0.11 ± 0.01 | 0.00 |
| SR3 | D. acidovorans | 2.41 ± 0.08 | 1.27 ± 0.03 | ++ | 44.74 ± 0.16 | 0.23 ± 0.06 | 1.00 ± 0.04 | 0.00 |
| SS5 | D. acidovorans | 5.87 ± 0.09 | 0.95 ± 0.04 | ++ | 43.31 ± 0.19 | 1.24 ± 0.11 | 0.27 ± 0.06 | 0.00 |
| TS1 | D. acidovorans | 9.62 ± 0.14 | 0.94 ± 0.02 | − | 0.00 | 0.00 | 0.00 | 0.00 |
| TS4 | D. acidovorans | 22.51 ± 0.48 | 1.23 ± 0.02 | − | 0.00 | 0.00 | 0.00 | 0.00 |
| AR2 | C. pratensis | 2.68 ± 0.08 | 0.46 ± 0.02 | − | 3.45 ± 0.20 | 0.26 ± 0.06 | 0.00 | 0.00 |
| AR3 | A. xylosoxidans | 0.13 ± 0.01 | 0.00 | ++ | 40.31 ± 0.20 | 2.11 ± 0.40 | 0.00 | 0.00 |
| AR4 | S. maltophilia | 20.60 ± 0.37 | 4.35 ± 0.08 | − | 0.00 | 0.00 | 0.00 | 0.00 |
| VR2 | V. paradoxus | 1.26 ± 0.07 | 0.44 ± 0.03 | ++ | 59.64 ± 0.21 | 0.00 | 0.19 ± 0.03 | 0.00 |
| VS3 | Rhizobium sp. | 0.56 ± 0.01 | 0.75 ± 0.03 | − | 0.00 | 0.00 | 0.00 | 2.18 ± 0.06 |
| VS4 | D. acidovorans | 1.02 ± 0.76 | 0.76 ± 0.03 | +++ | 71.83 ± 0.15 | 0.00 | 0.11 ± 0.01 | 0.00 |
Trp+, indole-3-acetic acid (IAA)-like compounds production in the presence of L-tryptophan; Trp-, IAA-like compounds production in the absence of L-tryptophan; Sid-CAS, qualitative production of siderophores (Sid) on agar with chrome azurol S (CAS), orange zone size: +++ large zone, ++ medium zone, + small zone, - no zone; Sid-CAS, quantitative production of siderophores production expressed as percent siderophores units (psu); HTS, quantitative production of hydroxamate-type siderophores (HTS); CTS, quantitative production of catechol-type siderophores (CTS); SI, phosphate solubilization index; Efficiency N/C: efficiency of nitrogen fix as the amount mg of nitrogen produced per gram of carbon utilized.