Abstract

Sustainable intensification of agriculture needs to discover efficient diazotrophs that sustain a high degree of nitrogen-fixation in intermittent environmental systems. This study reports the account of the isolation and molecular characterization of a novel, efficient, and non-symbiotic nitrogen fixer, Pseudomonas monteilii strain B12, isolated from the rhizosphere of Musa sp. (banana). Upon screening on the nitrogen-free Jensen agar, an unprecedented nitrogen-fixing index of 9.99 ± 0.52 in 5 days and the attainment of 39.54 ± 1.00 ppm nitrogen concentration in 24 hours. A significant physiological characteristic of B12 was the high-level correlation between the biological nitrogen fixation (BNF) and the rapid rise of the medium alkalinity (pH 6.06 ± 0.02 to 7.68 ± 0.15). The Nesslerization method was used to confirm the production of ammonium quantitatively and the highest ammonium concentration was 70.26 ± 2.33 ppm (pH reached a high of 7.66 ±0.22 at 72 hours. The vivo assay, though it indicated no influence of B12 bio-priming on germination kinetics, tended to make early-stage vigor much quicker, and the overall seedling length raised by 58.8%. Most importantly, strain B12 has high biotechnological potential because of its strong resistance to cold stress, salinity, and osmotic fluctuation, which gives high field stability in the degraded soils. Taxonomic identification of the strain P. monteilli was done by 16S rRNA sequencing. This research provides the initial indication of P. monteilii as a high-performing diazotroph in the banana rhizosphere, making it an elite inoculant in the creation of multi-stress resilient biofertilizers to facilitate global sustainable agriculture.