Plant Growth-Promoting Activity of Pseudomonas aeruginosa OD13 in Tomato Plant

Aims: The study aimed at assessing the plant growth-promoting properties of the Pseudomonas aeruginosa strain OD13.

Place and Duration of Study: The research was conducted at the Department of Plant Pathology, College of Agriculture, Odisha University of Agriculture and Technology, Bhubaneswar, Odisha, between September 2019 and March 2022.

Methodology: PGPR (Plant Growth Promoting Rhizobacteria) inoculation can increase crop yield and quality in a range of important crops including cereals, legumes, vegetables, and fruits. In addition to enhancing plant growth, PGPR can also improve soil health by increasing nutrient availability and reducing the need for chemical fertilizers and pesticides. Overall, the use of PGPR is a promising strategy for sustainable agriculture, as it offers a natural and eco-friendly alternative to conventional methods of plant growth enhancement. In the present study, The Pseudomonas isolates were obtained from the rhizosphere of solanaceous crops grown in various districts of Odisha. Tomato seeds were used in the experiment, with two groups: one control group and another group treated with the Pseudomonas aeruginosa strain OD13. The germination percentage, seedling height, plant height (including root length and shoot length), fresh weight, and dry weight were measured after a 30-day incubation period. The production of indole-3-acetic acid (IAA), Hydrogen cyanide (HCN), siderophore, hydrolytic enzymes, phosphate solubilization ability, heavy metal, and antibiotic sensitivity were also tested. Additionally, biofilm formation was evaluated by motility assay.

Results: Pseudomonas isolate significantly enhanced seed germination (90%), root length (6.25cm), shoot length (23.50cm), fresh weight (1.345g), and dry weight (0.085g) of tomato plants. It produced IAA, HCN, siderophore, protease, and lipase and showed phosphate solubilization ability in culture medium. The isolate was found to colonize in and around the tomato root system due to the presence of swimming and twitching motility. Moreover, it was highly resistant to zinc sulphate, ferric chloride, and copper sulphate, as well as conventional antibiotics like tetracycline.

Conclusion: Pseudomonas aeruginosa strain OD13 demonstrated great potential as an inoculant for tomato plants and as a suitable model system for studying the genetics of plant growth promotion by beneficial rhizobacteria.