Isolation and characterization of plant growth promoting rhizobacteria (PGPR) from rhizosphere of major crops grown in Marathwada region of Maharashtra, India

Microbes have been used for human wellness since ancient times, and this practice continues till today, albeit with more sophisticated methods. PGPR (Plant Growth-Promoting Rhizobacteria) are group of free-living bacteria that exhibit a range of advantageous traits and are highly suitable as biofertilizer agents. The present study characterized the rhizobacteria associated with cereal, pulse and vegetable crop plant i.e. maize (Zea mays), soybean (Glycine max), and chilli (Capsicum annuum) from different regions of Marathwada. Bacterial isolates were acquired and underwent screening to assess their diverse plant growth-promoting characteristics, including solubilization of phosphate, potassium, zinc and production of siderophores along with indol-3-acetic acid. Isolates exhibiting multiple functional abilities were then chosen for further analysis, involving morphological and biochemical characterization. Total three soil samples (one from each crop types) were collected and among them, 43 microbial strains were isolated from the rhizospheric soils of different sites. Cultural and morphological observations of bacterial isolates were recorded. A total of 15 isolates were chosen for the initial screening based on the morphological properties. Out of total 15 isolates, six isolates were selected, based on the quantity and effectiveness of plant growth promoting features demonstrated, additional screening for the best bacterial isolates was conducted. This research highlights the significance of isolating and screening PGPR for a variety of plant growth promoting traits and bio-control features, evaluating the promising strains, and finding rhizobacterial strains that can adapt to various environmental and soil conditions. These selected PGPR isolates could be utilized as biofertilizer formulations after some field trials on different economically important crops under agro-climatic conditions in Maharashtra region.