Deciphering the biocontrol mechanisms of Bacillus spp. against early leaf spot of groundnut: a link between antibiotic genes and induced systemic resistance

Rohini Verma Ananya Jain A. Puyam P. Jambhulkar Shubham Trivedi Kuleshwar Prasad Sahu Usha Ashutosh Singhd Vaibhav Singh U. Pankaj

Sep 2026 · Archives of Phytopathology and Plant Protection · Vol 59, pp. 1597 - 1625 · 0 citations · 70 references

Abstract

Abstract Bacillus subtilis BC1R, B. pumilus BC2R, and B. safensis RLBCAU demonstrated strong in vitro antagonistic activity against major soil-borne pathogens, including Macrophomina phaseolina, Sclerotium rolfsii, and Aspergillus niger, as well as foliar pathogens such as Alternaria tenuissima and Cercospora arachidicola. Treatment with these Bacillus strains also stimulated host resistance, as evidenced by histopathological changes. Genomic analysis revealed three major biosynthetic gene clusters associated with iturin, fengycin, and surfactin production in all three strains. Field application of Bacillus spp., involving soil application (20 g/plot), seed treatment (2 g/kg seed), and two foliar sprays (20 g/3 L water), effectively reduced C. arachidicola disease severity. The disease severity index (DSI) reduction ranged from 20–26.25%, with 37.5–52.88% reduction over the control. The consortium of all three strains recorded the lowest DSI (15.04%) and highest reduction over control (64.19%), highlighting its potential for biological disease management.

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