TABLE 2.
Biochemical characteristics of Pseudomonas strains Q2-87, 1M1-96, and Q8r1-96
| Characteristic | Q2-87 | 1M1-96 | Q8r1-96 |
|---|---|---|---|
| GC-FAME analysis | P. fluorescens biovar II | P. fluorescens biovar II | P. fluorescens biovar II |
| Growth with SCSa | |||
| Trehalose | − | − | + |
| Ethanol | − | + | + |
| Benzoate | − | − | + |
| 2-Ketogluconate | + | − | + |
| Valerate | − | − | + |
| dl-Norleucine | + | − | − |
| l-Proline | − | + | + |
| Casein hydrolysis | + | − | + |
| Gelatinase (plate) | + | − | − |
| In situ DAPG productionb | |||
| ng/g of root (SE) | 25.0 (8.3) | 141.5 (38.3) | 128.1 (90.5) |
| ng/105 CFU (SE) | 0.8 (0.5) | 2.0 (0.3) | 0.3 (0.2) |
Growth (+) or no growth (−) on various substrates as a sole carbon source (SCS). A total of 53 carbon sources were tested. Assays were performed in Stanier's basal medium. Those carbon sources that showed differential responses by the three isolates are presented here. The other carbon sources for which strains Q2-87, 1M1-96, and Q8r1-96 gave the same response were l-arabinose (+), cellobiose (−), d-fructose (+), d-glucose (+), lactose (−), maltose (−), d-mannitol (+), l-rhamnose (−), d-ribose (+), d-sorbitol (+), sucrose (+), d-xylose (+), adonitol (−), erythritol (−), glycerol (+), geraniol (−), i-inositol (+), sebacic acid (−), acetamide (−), adipate (−), butyrate (−), citraconate (−), d-gluconate (+), M-hydroxybenzoate (−), dl-lactate (+), L-malate (+), pelargonate (+), propionate (+), quinate (+), succinate (+), L-tartrate (−), B-alanine (+), d-alanine (+), betaine (+), glycine (−), l-histidine (+), d-tryptophan (−), l-valine (+), dl-arginine (+), benzylamine (−), butylamine (−), putrescine (+), mesaconate (−), dl-glycerate (+), l-tryptophan (−), and methanol (−).
Production of DAPG on the roots of wheat grown in raw Quincy virgin soil for 4 weeks. Wheat seeds were treated with Q2-87, 1M1-96, or Q8r1-96 at a density of approximately 104 CFU seed−1. Mean values of three replicates are presented. For every replicate, five pots with 25 plants each were used. DAPG production was determined by HPLC and is expressed as the total amount of DAPG produced per gram of root fresh weight (ng g of root−1) and as the amount of DAPG produced per population unit (105 CFU) of the introduced strains. For both parameters, no statistically significant differences were observed between the three strains (Tukey's studentized range test, α = 0.05).