Validation and Evaluation of Plant Growth Promoting Potential of Rhizobacteria Towards Paddy Plants

Abstract

This study aimed to characterize, validate, and evaluate the plant growth potential of bacterial isolates (E-2, T-2, and T-1) to determine their suitability for application as biofertilizers and/or plant-biostimulants. The plant growth-promoting potential of bacteria (E-2, T-2, and T-1) has been validated in a hydroponic study on paddy plants by inoculating bacterial isolates and monitoring the phenotypic and plant growth responses. The applicability of bacteria was tested based on their tolerance to salinity, susceptibility to antibiotics, and identification based on 16S rDNA sequencing. The isolates E-2, T-2, and T-1 improved plant growth variably and significantly (P < 0.05 at 95% confidence interval) when inoculated into the plant growth matrix, ensuring nutrient availability to the plants grown under a nutrient (nitrate or phosphate) deprived growth matrix. Isolates E-2, T-2, and T-1 grew at salt (NaCl) concentrations of 7%, 6%, and 6%, respectively, and were tolerant to saline conditions. Although these three isolates exhibited resistance to certain antibiotics, they were susceptible to a large number of readily available antibiotics. Isolates E-2, T-2, and T-1 were identified as Klebsiella sp. strain BAB-6433, Citrobacter freundii strain R2A5, and Citrobacter sp. DY1981 respectively, and all of these may be assigned to Risk-Group-2 and hence are safe in view of their susceptibility to readily available antibiotics. Hence, these isolates are promising for extensive evaluation as bioinoculants to ecologically improve soil quality, fertility, crop growth, and yield.

Isolation, selection and characterization of salt and temperature tolerant plant growth promoting rhizobacteria.

“…This was followed by isolates HB4A1, HB4N3, and HB8P1, which also exhibited notable tolerance to salts. Kumari et al, (2022) presented similar ndings in their research. They identi ed isolates E-2, T-2, and T-1, which displayed growth at salt (NaCl) concentrations of 7%, 6%, and 6%, respectively.…”

Exploration and Profiling of Potential Thermo-alkaliphilic Bacillus licheniformis and Burkholderia sp. from varied Soil of Delhi region, India and their Plant Growth-Promoting Traits

“…De O. Nunes et al 2023;Kumari et al 2022). The observed improvements in shoot and root parameters, as well as the promotion of root exudation of essential metabolites, parallel the positive effects reported in the hydroponics experiments(Rekha et al 2020).…”

Bio-fertilizers for sustain agricultural production and improve soil health

“…Different soil silicates are converted by Silicate Solubilizing Bacteria (SSB) into ortho silicic acid, which is accessible to plants and helps to increase crop yield and improve crop growth and development. Many bacteria, such as Bacillus caldolytyicus, Bacillus mucilaginosus or siliceous, Proteus mirabilis, Pseudomonas spp., and Penicillium spp., have been shown to discharge silica from likely silicates [26,4] . Silicate minerals contain potassium, calcium, magnesium, iron, and zinc in addition to silicon, so SSB inoculating the soil with this substance aids the pant by releasing a number of these nutrients [15] .…”