Synergistic enhancement of water deficit resilience in lentil (Lens culinaris) through silicon application and non-rhizobial bacterial co-inoculation

Aims

Drought stress significantly impacts crop yields and food security, particularly for legumes like lentil (Lens culinaris), which depend on symbiotic relationships for nitrogen fixation. This study investigated the synergistic impacts of silicon (Si) and plant growth-promoting non-rhizobial bacteria on enhancing drought resilience in the lentil plant with its symbiotic partner.

Methods

We isolated multiple rhizobial and non-rhizobial bacterial strains from lentil nodules and the rhizosphere. We characterized their seed germination rates, drought tolerance, and plant growth-promoting metabolites. Additionally, we investigated the effects of these isolates—both individually and in combination with varying concentrations of Si—on nodulation, as well as the morphological, physiological, and nutritional parameters of lentil plants under water deficit stress.

Results

The results demonstrated that co-inoculation of lentils with selected non-rhizobial strains, alongside Si application, significantly improved plant height, root length, biomass, and nodule formation under simulated water deficit conditions. Specifically, treatments including Si markedly increased nutrient uptake, particularly nitrogen, phosphorus, and potassium, thereby enhancing overall plant health. Physiological assessments revealed that combined treatments reduced oxidative stress markers, such as proline and malondialdehyde, improving leaf relative water content and mitigating the adverse effects of water deficit stress. Molecular identification of effective bacterial isolates (Rhizobium leguminosarum E10, Pseudomonas helmanticensis Rh23, and Pseudomonas frederiksbergensis Rh32) showed their potential roles in promoting plant growth and symbiotic efficiency.

Conclusion

These findings highlight the potential of integrating Si fertilization and beneficial microbial inoculants in sustainable agricultural practices to improve lentil cultivation under drought conditions. This study emphasizes a cost-effective and environmentally friendly strategy for enhancing the resilience of legumes, thus contributing to food security in the face of climate change.