Table 1.

Culture-dependent approach used to monitor plant growth-promoting bacteria and root interaction.

Strains	Experimental conditions	Microbial media	Plant substrate	Results	References
Pseudomonas sp. G1Dc10 Paenibacillus sp. G3Ac9 Sphingomonas azotifigens DSMZ18530	Gnotobiotic conditions in controlled-environment chamber (16-h light/8-h dark, 18–23°C)	TY agar	Modified Evans medium supplemented with 8% agar	Colonization density in the rhizoplane and in the leaves was about 9 and 4 log10 CFU/g, respectively. Colonization was more abundant in the rhizoplane than in plant tissues.	Castanheira et al., 2017
Pseudomonas sp. VM1449 Pseudomonas sp. VM1450 Pseudomonas sp. VM1453	Pots (16-h light/8-h dark, 20–25°C)	PCA containing 100 µg/ml kanamycin	Sterilized compost/vermiculite (3:1 ratio)	The three bacterial strains showed different colonization behavior (CFU/g) for rhizosphere, interior root tissues stems or leaves	Germaine et al., 2004
Burkholderia sp. WPB Rhizobium tropici PTD1 Rahnella sp. WP5	Axenic conditions in growth chamber	MG/L with 100 µg/ml of gentamycin and carbenicillin	N-free MS agar	Higher endophyte populations (CFU/g) were observed in the roots when compared with the stem and leaves	Kandel et al., 2015
Azotobacter chroococcum HKN-5 Bacillus megaterium HKP-2 Bacillus mucilaginous HKK-2 Glomus mosseae Glomus intraradice	Pots in greenhouse (20 ± 4°C; 87 days)	Specific media for N-fixing bacteria, P solubilizer and K solubilizer	Soil (pH 5.46, organic matter 1.08%, total N 0.062%, total K 7,408 mg/kg, total P 1,090 mg/kg)	The population size of the inoculated rhizobacteria varied in accordance with the levels of fertilization and AMF colonization in the rhizosphere	Wu et al., 2005
Azotobacter chroococcum Bacillus megaterium Bacillus mucilaginous Glomus fasciculatum Glomus mosseae	Greenhouse (21 ± 5°C; 45 days)	Differentiating media for N-fixing bacteria, P solubilizer and K solubilizer	Sterilized soil (pH 7.32, EC 0.14 dS/m, total C 1.92%, total N, 0.19%, total K 2,063 ppm)	Root colonization by AMF was increased in the presence of bacterial consortium application in comparison to individual inoculation treatments	Khalid et al., 2017
Azotobacter strain ST3 Azotobacter strain ST6 Azotobacter strain ST9 Azotobacter strain ST17 Azotobacter strain ST24	Pot house; sampling at 30, 60, and 90 days	Nutrient agar	Four different unsterilized saline soil	Survival of inoculated strains increased up to 60 days of sampling	Chaudhary et al., 2013
Azotobacter chroococcum 76A	Greenhouse (10 cm plastic pots)	LG agar	Pure peat moss under salt stress	The bacterial strain was able to grow in the rhizosphere of tomato plants under abiotic stress conditions increasing of 1 Log	Van Oosten et al., 2018
Azotobacter chroococcum Mac 27L	Pots; sampling after 30 and 60 days of growth	Burks medium plates with and without X-gal	Unsterilized soil	The bacterial strain was able to survive in the rhizoplane of Brassica campestris up to 30 days after sowing	Solanki and Garg, 2014
Azotobacter chroococcum AZ1 Azotobacter chroococcum AZ2 Glomus mosseae Glomus fasciculatum	Plots, temperate rainfed conditions	Nutrient agar medium, coal-vitamin medium, potato-dextrose supplemented with Rose-Bengal and streptomycin (30 g/ml)	Solarized, disinfected and natural soil plots (21% sand, 35.7% silt 43.3% clay; pH 7.4)	An increase of concentration of bacteria and/or fungal strains in the inoculated tests has been registered	Sharma et al., 2011
Azotobacter chroococcum Azospirillum brasilense Glomus fasciculatum	Open field	Jensen's medium and N-free maltase medium	Soil (pH 7.12, organic carbon 9.6 g/kg)	Viable counts of microbial population in the rhizosphere increased significantly in all the treatments over control but decreased under chemical fertilizers treatment	Singh et al., 2013