Bioprospecting of Multi Trait Plant Growth Promoting Bacillus altitudinis from Phosphate Rich Soil

Abstract

Phosphate Solubilizing Bacteria (PSB) has the natural ability to liberate unavailable phosphorus (as a result of microbial metabolism extracellularly) from soil, rocks, and mines thereby increasing its availability for plants. The main mechanism behind this is the production of mineral dissolving compounds, such as organic acids, protons, hydroxyl ions, and CO₂. The current study was conducted to explore the potential of a phosphate solubilizing bacteria which are isolated from rock phosphate mine in Rajasthan for enhancing the growth of Zea mays (maize) plants. Out of total of 137 bacterial isolates, one bacterial isolate RJ-11 was found to have multiple plant growth promoting (PGP) properties. Its phosphate solubilization ability was observed with solubility index (PSI) of 5.15. The potential isolate RJ-11 was found to solubilize tri calcium phosphate (Ca₃(PO₄)₂) at a rate of 790.67 mg L-1. RJ-11 was found positive for potash solubilization, zinc solubilization, and siderophore production. On the basis of morphological and molecular characterization, isolate RJ-11 was identified as Gram positive bacterium, Bacillus altitudinis. LabID-B197 was assigned to B. altitudinis for further greenhouse pot experiments. Greenhouse pot experiments demonstrated that maize plants inoculated with B197 incorporated more phosphate which was observed as increase in germination percentage, increased shoot length (155%) and root length (45%), and much higher biomass weights than those plants without any added bacteria or controls. The result of present study indicates that B. altitudinis is a unique bacterium with multiple plant growth promoting properties and could act as potential bio fertilizer to improve the plant growth and develop cost-effective and sustainable agriculture practices.

Keywords:

• Bacillus altitudinis
• biofertilizer
• PSB
• siderophore

Ethical approval

This is an observational study. The IPL TIC Center has confirmed that no ethical approval is required.

Author contributions

All authors contributed to the study conception and design. Material preparation, data collection, and analysis were performed by Pallavi and Dr. Vimala Prakash. The first draft of the manuscript was written by Dr. Sonia Arora, and statistical analysis and second draft of manuscript was written by Dr. Gaurav Sood. All authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

All data generated or analyzed during this study are included in this published article.

Additional information

Funding

We are thankful to IPL TIC Center and the in-house funding of IPL Biologicals for providing funds for this study.