Molecular characterization and validation of zinc solubilization potential of bacteria isolated from onion (Allium cepa L.) rhizosphere

Bibliographic Details
Title: Molecular characterization and validation of zinc solubilization potential of bacteria isolated from onion (Allium cepa L.) rhizosphere
Authors: Shivi Choudhary, Baljeet Singh Saharan, Rajesh Gera, Shubham Kumar, Minakshi Prasad, Anshika Gupta, Joginder Singh Duhan
Source: The Microbe, Vol 4, Iss , Pp 100145- (2024)
Publisher Information: Elsevier, 2024.
Publication Year: 2024
Collection: LCC:Microbiology
Subject Terms: Zn solubilizing bacteria, Onion rhizosphere, AAS, FE-SEM-EDS, pH reduction, Microbiology, QR1-502
More Details: Zinc (Zn) is essential for optimal plant growth and nutrition, while zinc-solubilizing bacteria (ZSB) enhance plant accessibility to zinc by converting its insoluble forms into usable ones. The primary objective of this research was to isolate and identify Zn-solubilizing strains from the onion rhizosphere and evaluate their ability to solubilize different insoluble Zn compounds, including ZnO, ZnCO3, and Zn3(PO4)2. Of the nineteen bacterial isolates retrieved, fifteen demonstrated the ability to solubilize inorganic Zn compounds based on plate assay techniques. The Zn-solubilizing bacterial strains, selected for their qualitative properties, underwent quantitative testing in broth culture using atomic absorption spectrophotometry (AAS) and Field Emission-Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (FE-SEM-EDS). Seven bacterial isolates with a high capacity to solubilize Zn were identified based on 16S rRNA gene amplification and sequence analysis. These isolates were affiliated with Pantoea eucrina, Pantoea dispersa, Pseudomonas aeruginosa, Bacillus velezensis, and Pseudomonas fluorescens. Notably, this study is the first to report the potential of Pantoea eucrina as a ZSB. The strain Pantoea eucrina ZSC9 exhibited the maximum Zn solubilization index (8.85) and the highest soluble Zn content (624 mg L−1) among the three insoluble Zn compounds, with ZnO being the most effectively solubilized on the 10th day of incubation in ZnO-enriched basal medium. All bacterial isolates were more effective at solubilizing ZnO than ZnCO3 and Zn3(PO4)2, and this solubilization led to a significant drop in the pH of the broth. Pantoea eucrina ZSC9 showed the maximum pH reduction (3.82) in a ZnO-supplemented medium, indicating a negative correlation between broth pH and Zn solubilization. Seven selected ZSB strains were assessed for their potential to enhance onion growth under pot house conditions. The results showed that inoculating onion seedlings with these ZSB strains significantly improved their growth. Among the strains tested, ZSC9, ZSC10, and ZSC17 were the most effective, enhancing growth attributes such as plant height, bulb diameter, fresh and dry weight of bulbs, Zn uptake by the plant, and overall bulb yield compared to other strains. These findings suggest that these ZSB isolates have great potential as biofertilizers to enhance plant growth and development.
Document Type: article
File Description: electronic resource
Language: English
ISSN: 2950-1946
Relation: http://www.sciencedirect.com/science/article/pii/S2950194624001122; https://doaj.org/toc/2950-1946
DOI: 10.1016/j.microb.2024.100145
Access URL: https://doaj.org/article/7572d9a66624463b8023b5e4dc831a01
Accession Number: edsdoj.7572d9a66624463b8023b5e4dc831a01
Database: Directory of Open Access Journals
More Details
ISSN:29501946
DOI:10.1016/j.microb.2024.100145
Published in:The Microbe
Language:English