Screening of Pseudomonas Species for Growth Promoting Potential of Rice (Oryza sativa L.) Under Temperate Conditions

Using agrochemicals in agriculture has led to significant environmental contamination, posing serious land, water, and air threats. Indiscriminate application of these chemicals renders agricultural ecosystems incapable of supporting life. Excessive use of nitrogen-based fertilizers such as nitrogen, phosphorous, potassium, urea, and organic manures, such as cow dung and decomposed vegetative waste often leads to nitrate infiltration into subsurface water bodies. This ongoing environmental degradation, including the deterioration of agricultural land, hampers plant growth and development, thus threatening plant productivity. Considering the rising demand for rice and the detrimental impacts of excessive chemical use, this study evaluated the plant growth-promoting potential of Pseudomonas species isolated from the rice rhizosphere. Thirty-two isolates were examined for their different plant growth-promoting rhizobacteria (PGPR) activities, such as producing Indole acetic acid (IAA), Hydrogen cyanide (HCN) and phosphorus solubilization. The amount of IAA ranged from 2.36 to 22.1 μg/mL. The highest IAA was produced by isolate PS-17K with a total production of 22.15 μg/mL. HCN production ranged from 5.37 to 25.37 μg/mL; isolate PS-17K showed the highest HCN production (25.37 μg/mL). The isolate PS-28K and PS-26K showed maximum solubilization efficiency of 536.89 and 459.47%, respectively. Using PGPRs was a promising solution for enhancing the growth of host plants and improving soil fertility.. KEYWORDS :Growth regulators, IAA, Phosphorus solubilization, Pseudomonas, Rhizobacteria, Soil fertility