Safar Ali, Adesh Kumar, Hemant Kumar Yadav, Ashwani Kumar, Niyaj Ahamad, Shambhoo Prasad and Shipra Mohan Tripathi
Abstract
Maize (Zea mays L.) is severely affected by banded leaf and sheath blight caused by Rhizoctonia solani, particularly under warm and humid agroecological conditions. The present study was conducted to isolate and characterize antagonistic plant growth-promoting rhizobacteria from maize rhizosphere soils of Eastern Uttar Pradesh for potential bio-control of R. solani. A total of twenty rhizobacterial isolates were obtained, among which seven showed notable inhibition of fungal growth under dual culture assay. Isolate NA 2 recorded the highest mycelial inhibition of 86%, followed by NA 6 with 76% inhibition, indicating strong antagonistic potential against the pathogen. The selected isolates also expressed important plant growth promoting traits, including ammonia production, indole-3-acetic acid production, phosphate solubilization, and zinc solubilization, suggesting their multifunctional role in plant growth enhancement and disease suppression. Molecular characterization of the most promising isolates through 16S rRNA gene sequencing identified them as Stenotrophomonas maltophilia. The amplification of an approximately 1500 bp 16S rRNA gene fragment, BLASTn analysis, and phylogenetic confirmation validated their taxonomic identity. The findings indicate that maize rhizosphere-associated S. maltophilia isolates possess significant antagonistic and plant growth-promoting attributes and may be explored as eco-friendly biocontrol agents for integrated management of banded leaf and sheath blight in maize.