Isolation and characterization of plant growth-promoting rhizobacteria from wheat rhizosphere and their effect on plant growth promotion

Abstract

The present study was conducted to characterize the native plant growth promoting (PGP) bacteria from wheat rhizosphere and root-endosphere in the Himalayan region of Rawalakot, Azad Jammu and Kashmir (AJK), Pakistan. Nine bacterial isolates were purified, screened in vitro for PGP characteristics and evaluated for their beneficial effects on the early growth of wheat (Triticum aestivum L.). Among nine bacterial isolates, seven were able to produce indole-3- acetic acid in tryptophan-supplemented medium; seven were nitrogen fixer, and four were able to solubilize inorganic phosphate in vitro. Four different morphotypes were genotypically identified based on IGS-RFLP fingerprinting and representative of each morphotype was identified by 16S rRNA gene sequencing analysis except Gram-positive putative Bacillus sp. Based on 16S rRNA gene sequence analysis, bacterial isolates AJK-3 and AJK-9 showing multiple PGP-traits were identified as Stenotrophomonas spp. while AJK-7 showed equal homologies to Acetobacter pasteurianus and Stenotrophomonas specie. Plant inoculation studies indicated that these Plant growth-promoting rhizobacteria (PGPR) strains provided a significant increase in shoot and root length, and shoot and root biomass. A significant increase in shoot N contents (up to 76%) and root N contents (up to 32%) was observed over the un-inoculated control. The study indicates the potential of these PGPR for inoculums production or biofertilizers for enhancing growth and nutrient content of wheat and other crops under field conditions. The study is the first report of wheat associated bacterial diversity in the Himalayan region of Rawalakot, AJK.

The Role of Soil Beneficial Bacteria in Wheat Production: A Review

“…Similarly, Shaharoona et al reported that N use efficiency increased in response to inoculation with Pseudomonas fluorescens at all fertilizer levels in wheat [167]. PGPR isolates significantly increased shoot and root length, shoot and root dry weight, grain weight per spike, shoot and root N content and also enhanced the N contents of inoculated wheat seedlings [168]. Barneix et al reported that inoculation of wheat with Bacillus simplex and Bacillus firmis resulted in consistent increase in dry matter and wheat grain quality.…”

Corn Yield and Foliar Diagnosis Affected by Nitrogen Fertilization and Inoculation with Azospirillum brasilense

“…The components released by A. brasilense responsible for stimulating root growth are indole-acetic acid (IAA), gibberellins, and cytokinins (Tien et al, 1979). The increase in root development caused by inoculation with Azospirillum is involved with several other effects.…”

Initial performance of maize in response to humic acids and plant growth-promoting bacteria

“…Several PGPB genera are being studied because of their ability to establish associations with economically attractive grasses, such as sorghum, rice, sugarcane and wheat (Idris et al, 2009;Pedrosa et al, 2011;Majeed et al, 2015). For maize, the results of plant growth promotion with PGPB inoculation of the genera Herbaspirillum and Azospirillium, are well documented, being the latter with registration in the Ministry of Livestock Farming and Supply for use in commercial formulations (Hungria et al, 2010).…”