Plant growth-promoting potential of 'Myroides gitamensis' isolated from virgin soils of Punjab

Phosphate-solubilizing (PS) and phosphate-mineralizing (PM) bacteria are considered vital for augmenting the plant growth through phosphorus mobilization and plant growth-promoting attributes. In the present study, a rhizospheric bacterium was isolated from the virgin land of Punjab, India and identified as 'Myroides gitamensis' BSH-3 through 16S rRNA sequencing. 'M. gitamensis' showed potential halo zone on Pikovskaya agar. The novelty of the study lies in the fact that plant growth-promoting potential of 'M. gitamensis' has not been studied earlier. It was able to solubilize 17.53-106.66 µg/mL of tricalcium phosphate and demonstrated a promising potential of mineralizing sodium phytate corresponding to 44.6-94.70 µg/mL at 28 °C. Variable PS and PM activity was observed at temperature range of 15-42 °C with the maximum activity observed at 28 °C after 96 h of incubation. The nitrogen fixation ability, hydrogen sulfide production, cellulose hydrolysis test and chitin degradation was found to be negative. High indole acetic acid (42.82 µg/mL), gibberellic acid (72.93 µg/mL), ammonia (22.58 µg/mL) production, phytase activity (0.49 pi/mL/min) and comparable amount of siderophore (28.55%) and acid phosphate activity (0.606 µM p-nitrophenol/ml/min) was shown by 'M. gitamensis'. Inoculation of wheat with 'M. gitamensis' in pot experiment showed increased shoot and root length by 30.58% and 38.32%. Fresh weight and dry weight was increased by 45.74% and 67.81%, respectively, compared to uninoculated control. These results demonstrate that 'M. gitamensis' has promising PS, PM and plant growth-promoting attributes to be used as a bio-inoculant to enhance plant growth and soil fertility.