Vol. 7, Issue 9, Part F (2025)

The present study investigates the potential of endophytic microorganisms for the production of phytohormones, particularly Indole-3-acetic acid (IAA) and Gibberellic acid (GA3), and their subsequent application as bioinoculants for plant growth promotion. A range of bacterial isolates including Acetobacter diazotrophicus, Azospirillum brasilens, Azoarcus spp, Burkholderia spp, Herbaspirillum spp, and Agrobacterium diazotrophicus were screened for their ability to produce phytohormones. Quantitative estimations of IAA and GA3 were carried out using spectrophotometric assays. Bioformulations were developed based on high-yielding isolates and tested in vitro and in vivo on maize, wheat, and pea seeds. Results demonstrated significant enhancement in seed germination, shoot elongation, and overall growth, indicating the potential of microbial phytohormones as sustainable alternatives to synthetic growth regulators.