A bioinspired approach to engineer seed microenvironment to boost germination and mitigate soil salinity

Area of Science:

• Agricultural Science
• Biomaterials Engineering
• Microbiology

Background:

• Global food security faces challenges from population growth, soil degradation, and agrochemical misuse.
• Seed enhancement technologies are crucial for improving crop resilience and yield in adverse conditions.
• Current seed enhancement methods focus on plant adaptation rather than engineering the seed's microenvironment.

Purpose of the Study:

• To develop a novel seed coating technology for improved seed germination and stress mitigation.
• To encapsulate and deliver biofertilizers, specifically rhizobacteria, using a silk fibroin-based biomaterial.
• To enhance crop yield and resilience to abiotic stressors like soil salinity.

Main Methods:

• Developed a biomaterial coating using silk fibroin and trehalose.
• Mixed the biomaterial with rhizobacteria (Rhizobium tropici CIAT 899) for seed application.
• Applied the coating to Phaseolus vulgaris seeds using dip coating or spray drying methods.
• Assessed the survival of rhizobacteria in the coating under anhydrous conditions.
• Evaluated the efficacy of the coated seeds in terms of germination, root nodulation, yield enhancement, and salinity mitigation.

Main Results:

• A micrometer-thick, transparent, and robust coating was formed via material assembly.
• The silk fibroin-trehalose coating supported the survival of non-spore forming rhizobacteria under anhydrous conditions.
• Rhizobacteria delivered via the coating successfully infected seedling roots, formed nodules, and enhanced crop yield.
• The seed coating demonstrated mitigation of soil salinity stress on crop growth.

Conclusions:

• The silk fibroin-trehalose biomaterial is a promising platform for encapsulating and delivering biofertilizers.
• This seed coating technology offers a viable strategy to improve agricultural sustainability and food security.
• The approach retrofits existing seed coating techniques, enabling precise delivery of beneficial microbes to enhance crop performance.