Abstract
Contamination of agricultural soil with heavy metals has become a serious concern worldwide. In the present study, Cr6+ resistant plant growth promoting Pseudomonas sp. (strain CPSB21) was isolated from the tannery effluent contaminated agricultural soils and evaluated for the plant growth promoting activities, oxidative stress tolerance, and Cr6+ bioremediation. Assessment of different plant growth promotion traits, such as phosphate solubilization, indole-3-acetic acid production, siderophores, ammonia and hydrogen cyanide production, revealed that the strain CPSB21 served as an efficient plant growth promoter under laboratory conditions. A pot experiment was performed using sunflower (Helianthus annuus L.) and tomato (Solanum lycopersicum L.) as a test crop. Cr6+ toxicity reduced plant growth, pigment content, N and P uptake, and Fe accumulation. However, inoculation of strain CPSB21 alleviated the Cr6+ toxicity and enhanced the plant growth parameters and nutrient uptake. Moreover, Cr toxicity had varied response on oxidative stress tolerance at graded Cr6+ concentration on both plants. An increase in superoxide dismutase (SOD) and catalase (CAT) activity and reduction in malonialdehyde (MDA) was observed on inoculation of strain CPSB21. Additionally, inoculation of CPSB21 enhanced the uptake of Cr6+ in sunflower plant, while no substantial enhancement was observed on inoculation in tomato plant.
Highlights
The region Jajmau, Kanpur, India presents about 400 tannery industries[2]
promoting rhizospheric (PGP) bacteria play a crucial role in alleviating the metal toxicity and exert ameliorating effects on plant growth and mineral uptake[15]
These rhizospheric bacteria promote plant growth through mineral phosphate solubilization, nitrogen fixation, indole3-acetic acid, siderophores, hydrogen cyanide, and ammonia production[16]. These microbes inhabiting the plant rhizosphere are essential to phytoremediation process due to their effects on enhanced biomass production, plant growth, anti-oxidative enzymes, and metal tolerance ability
Summary
The region Jajmau, Kanpur, India presents about 400 tannery industries[2]. For more than last two decades the treated effluent with high metal concentration is extensively used in the irrigation of ~2100 acres of agricultural land in this region[3]. That results in the production of reactive oxygen species (ROS) causing an increase in membrane permeability due to MDA formation/lipid peroxidation[6] Under such conditions, plants regulate their metabolism by initiating biochemical changes to protect them from the stress-induced oxidative injury[7,8]. PGP bacteria play a crucial role in alleviating the metal toxicity and exert ameliorating effects on plant growth and mineral uptake[15] These rhizospheric bacteria promote plant growth through mineral phosphate solubilization, nitrogen fixation, indole3-acetic acid, siderophores, hydrogen cyanide, and ammonia production[16]. These microbes inhabiting the plant rhizosphere are essential to phytoremediation process due to their effects on enhanced biomass production, plant growth, anti-oxidative enzymes, and metal tolerance ability. Application of selected rhizospheric bacteria can simultaneously increase metal phytoavailability, and reduce toxicity, allowing the plant to produce more biomass and accumulate large amount of metals[11]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
