Influence of <i>Kosakonia</i> sp. on the Growth of <i>Arachis hypogaea</i> L. on Arid Soil

Abstract

The current study focused on enumerating the potential plant growth-promoting rhizobacteria (PGPR) from the rhizosphere of Arachis hypogaea L. Among the several colonies grown on an Ashby plate, only seven isolates (Ah1 to Ah7) had nitrogen-fixing potential. The Ah4 isolate showed higher potential for plant growth-promoting (PGP) activities than the other isolates. This isolate was recognized as Kosakonia sp. MGR1 through 16S rRNA sequencing with 99.7% similarity to nitrogen-fixing Kosakonia genus and 61% match with K. cowanii in phylogenetic tree analysis. Kosakonia sp. MGR1 had the potential to produce an excellent quantity (26.17 µg·mL−1) of indole-3-acetic acid (IAA) in 6% tryptophan-enriched media than the other concentrations (2%, 4%, 8%, and 10%). Additionally, it contained remarkable phosphate-solubilizing efficiency of tricalcium phosphate (29.3 µg·mL−1) in 5 days of incubation. The growth conditions of Kosakonia sp. were optimized as 35 °C, pH 7.5, and 48 h of incubation with glucose. The isolate MGR1 produced 96.35 ± 3.45, 89.6 ± 5.61, and 99.21 ± 5.24 µg·mL−1 of IAA, nitrogen, and soluble phosphate, respectively. Furthermore, Kosakonia sp. MGR1 had the potential to enhance the growth and biomolecule contents of A. hypogaea L. The results concluded that Kosakonia had admirable PGP activities; hence, it showed a significant impact on the active growth and biomolecules of A. hypogaea L.

Keywords

• <i>Arachis hypogaea</i> L.
• Kosakonia sp.
• N₂ fixation
• phosphate solubilization
• rhizosphere soil