Improving growth of Solanum melongena L. exposed to lead (Pb) stress using gibberellic acid in combination with Agrobacterium fabrum

•fabrum + 30GA3 treatment significantly improved brinjal growth parameters in the presence of lead (Pb) toxicity.•The treatment A. fabrum + 30GA3 led to a substantial increase in chlorophyll content and photosynthetic efficiency, especially under Pb toxicity.•Elevated concentrations of vital nutrients, including nitrogen (N), phosphorus (P), and potassium (K), were observed in both root and shoot tissues where A. fabrum + 30GA3 treatment was applied in Pb toxic conditions. Lead (Pb), as heavy metal, poses substantial threats to plant health, impeding growth, disrupting nutrient uptake, and inducing oxidative stress. Its interference with crucial processes such as photosynthesis and water uptake, combined with its capacity to accumulate in plant tissues, results in stunted development and compromised overall productivity. To address this issue, the application of gibberellic acid (GA3) emerges as an effective amendment, promoting seed germination, stem elongation, and flowering. Additionally, the inoculation of rhizobacteria, specifically Agrobacterium fabrum (A. fabrum), offers resistance, improved nutrient uptake, and enhanced growth under conditions of heavy metal toxicity. Therefore, the present study was designed to investigate the impact of GA3 and A. fabrum on Solanum melongena L. cultivated under Pb toxicity. The experiment comprised four treatments: control, A. fabrum, 30 mg/L GA3 (30GA3), and A. fabrum + 30GA3, applied in four replications following a completely randomized design. Results indicated that A. fabrum + 30GA3 significantly enhanced Solanum melongena L. shoot and root length, fresh and dry weight over the control under Pb stress. Furthermore, a notable increase in Solanum melongena L. chlorophyll contents, stomatal conductance, transpiration rate, and photosynthetic rate over the control under Pb stress validated the effectiveness of A. fabrum + 30GA3. Additionally, improvements in N, P, and K concentration in roots and shoots confirmed the efficacious functioning of A. fabrum + 30GA3 from the control under Pb stress. In conclusion, A. fabrum + 30GA3 is recommended as an amendment for the mitigation of Pb stress in Solanum melongena L.