# Harnessing Silicon and Nanosilicon Formulations with Rhizobium/Bradyrhizobium for the Sustainable Enhancement of Biological Nitrogen Fixation in Legumes and Climate Change Mitigation

## TL;DR

This review explores how silicon and nanosilicon, when used with rhizobia, can improve legume growth, nitrogen fixation, and soil health while helping combat climate change.

## Contribution

The novelty is an integrative perspective linking molecular mechanisms of nanosilicon with ecological and climate-smart agricultural applications.

## Key findings

- Si-NPs enhance rhizobia-legume symbiosis by improving nodulation and stress resistance.
- Nanosilicon improves soil structure and microbial diversity, supporting sustainable agriculture.
- Research gaps include standardized protocols and large-scale validation for nanosilicon applications.

## Abstract

Silicon has long been recognized as a beneficial element in plant biology. Recent advances in nanosilicon technology have revealed its transformative potential in legume-rhizobia symbiosis. This review synthesizes current knowledge on how silicon and SiO2 nanoparticles (Si-NPs) influence nodulation, microbial metabolism, and soil–plant interactions. We highlight emerging evidence that Si-NPs enhance symbiotic signaling, strengthen infection pathways, and mitigate oxidative stress, thereby supporting nitrogen fixation efficiency. Beyond the rhizosphere, nanosilicon improves soil structure, microbial diversity, and plant resilience under abiotic stress, offering a multifaceted approach to sustainable agriculture. The novelty of this review lies in its integrative perspective, connecting molecular mechanisms with ecological impacts and climate-smart applications. By examining Si-NPs across three domains—soils, rhizosphere metabolites, and plants—we provide a framework for understanding their role in enhancing productivity while reducing environmental costs. Importantly, we identify critical research gaps, including the need for standardized application protocols, large-scale field validation, sustainable nanosilicon production, and robust regulatory frameworks. These insights position nanosilicon as a promising tool for advancing legume productivity, reducing reliance on synthetic fertilizers, and contributing to global food security. This review underscores silicon’s potential not only as a plant nutrient but also as a strategic agent in climate-resilient agriculture.