Context & Novelty

• First comprehensive effort to isolate and characterize rhizobia from Phaseolus vulgaris L. (common bean) root nodules across diverse altitudinal zones of the Indian Himalaya (Uttarakhand).

• Integrates morphological, biochemical, molecular, and functional analyses with nif gene expression profiling to identify efficient strains for nitrogen fixation under cold-adapted, high-altitude conditions.

Expected Outcomes

• Diverse rhizobial strains isolation from common bean root nodules collected across varying altitudes of the Himalayan region.

• Morphological, biochemical, and molecular characterization is expected to reveal significant diversity, adaptability, and functional traits of native rhizobia.

• Genetic fingerprinting (BOX-PCR) is anticipated to demonstrate high variability among isolates, with possible correlations between genetic clusters and altitudinal/climatic adaptation.

• Functional screening to confirm key plant growth-promoting traits such as nitrogen fixation, siderophore production, phosphate solubilization, and indole-3-acetic acid (IAA) production, highlighting their contribution to soil fertility and crop performance.

• nifH gene expression analysis for identification of highly efficient strains with superior nitrogenase activity, ensuring better symbiotic efficiency under nitrogen-limiting conditions.

• Promising rhizobial development for carrier-based bioinoculant formulations tailored for Himalayan soils and climates.

• Reduction in dependency on chemical fertilizers.

• Finally contribution towards improved soil health, sustainable agricultural practices, and enhanced livelihoods of farming communities in Uttarakhand.

Impact & Applications

• Provides a baseline understanding of native rhizobial diversity in fragile Himalayan soils and their ecological adaptation to variable altitude, temperature, and nutrient conditions.

• Demonstrates the practical applicability of rhizobial bioinoculants for sustainable agriculture, reducing environmental impact and fertilizer dependence.

• Offers direct benefits to farmers and local communities by improving crop productivity, nutritional quality, and socioeconomic resilience in high-altitude regions.

• Contributes to conservation of native microbial resources and advances the integration of molecular tools (nifH expression) with traditional microbiological approaches for strain selection.