Exploration of metabolites of limestone Actinobacteria as fungal plant pathogen inhibitors and plant growth promoters
1Reshma N. Sirasagikar, 2Bushra Ustad, 3Sudarshan Ashok and *Dayanand Agsar
A-DBT Research laboratory, Department of Microbiology, Gulbarga University, Kalaburagi-585106 (India) *Corresponding author: reshmasirasagikar@gmail.com Ph- 7019877817
ABSTRACT
Agriculture is pivotal in India, yet the heavy use of chemical fertilizers adversely affects ecosystems. This study seeks eco-friendly alternatives to beneficial phyto micro-biomes. It involves isolating 200 actinobacterial strains from Andhra Pradesh’s limestone quarries. These strains combat fungal pathogens: Fusarium oxysporum, Rhizoctonia bataticola, Botrytis cinerea, Sclerotium rolfsii (affecting Chickpea), and Macrophomina phaseolina (impacting sorghum). Initial screening revealed 10 actinobacterial isolates with fungal inhibition. Further testing, notably agar well diffusion, highlighted DRAH-24 as the most potent. Its metabolite strongly countered Sclerotia rolfsii (22 mm zone) and Macrophomina phaseolina (37 mm zone). Molecularly, DRAH-24 shares 99.80% homology with Streptomyces rochei OQ119704. DRAH-24’s plant growth promotion and enzymatic prowess were also encouraging. This comprehensive research underscores Streptomyces rochei OQ119704’s potential. It shows promising antagonistic traits and the ability to enhance plant growth and perform enzymatic functions. Consequently, it emerges as a viable candidate for integrating into agriculture—an eco-friendly substitute for chemical pesticides