Comparative Study of Bacillus-Based Plant Biofertilizers: A Proposed Index

Area of Science:

• Agricultural Microbiology
• Plant Pathology
• Soil Science

Background:

• The agricultural biofertilizer market is expanding, offering diverse microbial solutions for plant growth and protection.
• Selecting effective microbial products for specific agricultural needs, such as drought resistance, presents a challenge for end-users.
• Bacillus species, particularly Bacillus amyloliquefaciens, are widely used as plant-growth-promoting rhizobacteria and bio-control agents.

Purpose of the Study:

• To isolate and characterize a novel strain of Bacillus velezensis for agricultural applications.
• To evaluate the efficacy of the isolated Bacillus velezensis strain as a plant-growth promoter, biofungicide, and drought stress protector.
• To develop a quantitative index for comparing the effectiveness of different Bacillus amyloliquefaciens group strains.

Main Methods:

• Isolation and identification of a Bacillus velezensis strain.
• Assessment of plant-growth promotion in pepper plants.
• Evaluation of fungicidal activity via antibiosis and antagonism assays.
• Analysis of potassium and phosphate solubilization and siderophore production.
• Application of probit regression and Delphi method to create the Agricultural Protection Against Stress Index.

Main Results:

• The isolated Bacillus velezensis strain demonstrated significant plant-growth promotion, fungicidal activity, and drought protection capabilities.
• Comparative analysis showed variations in efficacy among commercial Bacillus amyloliquefaciens strains.
• The developed Agricultural Protection Against Stress Index provided a numerical basis for comparing the overall performance of the tested strains.

Conclusions:

• The isolated Bacillus velezensis strain shows potential as a multi-functional biofertilizer for sustainable agriculture.
• The Agricultural Protection Against Stress Index offers a valuable tool for selecting superior microbial strains for agricultural applications.
• Further research can refine the index and explore the strain's performance under diverse field conditions.