Enhancing soybean nodulation through orange peel and Bacillus velezensis probiotic inoculation

Overview

This research investigates a sustainable probiotic approach to enhance soybean growth and nodulation by combining orange peel (OP) with Bacillus velezensis (Bv) spores. The strategy addresses a key challenge in agriculture: the inconsistent performance of plant growth-promoting rhizobacteria (PGPR) under field conditions, often caused by poor microbial survival and root colonization due to competition with native soil bacteria.

The core innovation lies in using OP as a carbon source that enhances Bv survival in soil and promotes the production of metabolites that attract beneficial Bradyrhizobium bacteria. These metabolites may stimulate nodule formation or increase root hair density, ultimately improving nitrogen fixation, above-ground biomass, and crop yield. The research aims to identify the specific metabolites responsible for these enhanced plant responses, enabling the development of more effective biofertilizer formulations.

Technical specifications

Research approach:

• Screening and selection of Bv strains capable of using pectin and OP as their sole carbon source to improve soil survival
• Testing Bv plus pectin inoculation to evaluate plant performance improvements
• Demonstrating that soybean response to Bv+OP increases nodule number and size, with effects being cultivar-dependent
• Investigating how the relationship between Bv metabolites (when consuming OP) and soybean root exudates influences plant response

Future validation methods:

• Hydroponic soybean seedling systems with seven treatment combinations of Bradyrhizobium japonicum USDA110, Bv strain AP193, and OP
• Root exudate extraction and analysis using Mass Spectrometry (MS)
• Potential for in-house MS analysis collaboration to reduce project costs

Technology readiness level

This research is at an early-to-mid stage of development. Initial screening has identified promising Bv strains and demonstrated positive effects of Bv+OP inoculation on nodulation. The next phase involves controlled hydroponic experiments to identify the specific metabolites driving plant response. The research requires funding to establish the hydroponic system and support technical personnel, with potential for collaborative MS analysis to accelerate metabolite identification and advance toward field-ready biofertilizer applications.