Application of
Root Associated Zinc solubilizing Bacillus proteolyticus strain SH 25 on growth
and augmentation of Zinc in Maize Plant
Chakraborty Shohini, Majumdar Sukanta, Gupta Santanu and Sil Sudipta Kumar
Res. J. Biotech.; Vol. 20(1); 217-224;
doi: https://doi.org/10.25303/201rjbt2170224; (2025)
Abstract
Zinc (Zn) stands out as a critical micronutrient crucial for the proper growth,
development and functioning of plants. Recent studies indicate that zinc exists
abundantly in soil, it predominantly persists in insoluble forms, hindering its
uptake by plants. Zinc solubilizing bacteria (ZSB) emerge as pivotal agents in facilitating
the transformation of insoluble zinc into soluble forms, thus aiding plant growth.
To address this issue, the current study aimed at isolating, screening, identifying
and characterizing efficient zinc solubilizing bacteria to enhance maize growth.
Numerous bacteria were isolated from the maize rhizosphere in the Northern region
of West Bengal by using the dilution plate technique. Screening involved the utilization
of ZnO, zinc ores, with only four bacterial strains exhibiting notable zinc solubilizing
capacity selected for further assessment. These strains underwent biochemical, morphological
and plant growth-promoting (PGP) activity evaluations.
The selected bacterial isolates, capable of solubilizing Zn, underwent further screening
for their ability to promote plant growth under sterile conditions. The identified
bacterium was classified as Bacillus proteolyticus (SH 25/OM584287) by molecular
identification through MALDI-TOF-MS analysis and 16S rDNA sequencing. This ZSB isolate
demonstrated various growth-promoting attributes including the production of organic
acids, contributing to its effectiveness in enhancing maize growth. ZnSO4 served
as the zinc source in this study. The impact of SH 25 on Zea mays (variety: SUPER
DON-9533) was quantified using the Zinc Transformation Index (ZTI) measured via
Atomic Absorption Spectroscopy (AAS).
