Unlocking the potential of indigenous plant growth-promoting bacteria for sustainable agricultural practices

The current research targeted to characterize the plant growth-promoting (PGP) traits of bacteria, isolated from soil samples, collected from organic and inorganic fertilized areas in Namakkal District, Tamil Nadu, India.A total of 60 bacterial strains were isolated, 33 from organic soil and 27 from inorganic soil.Biochemical assays were used to identify and characterize the bacterial isolates to evaluate their PGP properties, such as the generation of hydrogen cyanide (HCN), ammonia, phosphate solubilization, indole-3-acetic acid (IAA), cellulase, amylase, protease activity, and nitrogen-fixing capacity.Among the isolates, Alcaligenes faecalis from organic soil exhibited strong PGP properties, including the highest phosphate solubilization and IAA production, along with ammonia and cellulase activity.It also demonstrated the ability to promote seed germination, with an 85% germination rate observed during testing.Further, cytotoxicity analysis using VERO cells indicated that A. faecalis had minimal cytotoxicity, with 95.8% cell viability, and ecotoxicity assessment using earthworms revealed no significant adverse effects.The potential isolate was identified through 16S rRNA gene sequencing, confirming its identity as A. faecalis.The results of this investigation indicate that A. faecalis isolated from organic soil holds great potential as a biofertilizer, offering enhanced plant growth and improved soil health.Its minimal cytotoxic and ecotoxic effects further highlight its safety for agricultural applications.These results evidenced the use of A. faecalis as an eco-friendly alternative to chemical fertilizers, contributing to sustainable agriculture and environmental preservation.