Evaluation of antifungal activity of Lysinibacillus fusiformis as a biocontrol agent against Rhizoctonia solani in soybean

Abstract

Introduction Rhizoctonia root rot has a wide host range and no resistant soybean cultivars exist, making it a serious problem. Methods The antifungal activity of 65 isolates of rhizobacteria against R. solani was evaluated. Results and Discussion The pathogen in the in vitro experiment was inhibited by nine rhizobacterial endophytes. The most effective rhizobacterial isolate was genus-level verified using 16S rDNA partial sequence analysis. The impact of the biocontrol isolate was investigated on R. solani infection in both greenhouse and field conditions. The rhizobacterial isolate considerably decreased the percentage of pre- and post-emergence damping-off and enhanced the plant survival compared to the untreated control grown in soil infected with R. solani. Lysinibacillus fusiformis treatment resulted in significantly stimulated antioxidant enzymes and total phenols. Transcript levels of the studied defense-related genes were considerably elevated after L. fusiformis treatment, according to quantitative RT-PCR data. Treatment of L. fusiformis in challenged plants achieved the highest levels of PR-1, PR-2, PR-10, and PR-12. The field experiments revealed that the biocontrol treatment method significantly reduced Rhizoctonia root rot incidence, stimulated plant growth, and increased yield. This research has uncovered a promising biocontrol bacterial isolate that might be used as a novel bioagent for controlling R. solani. After further toxicological and ecotoxicological evaluation, formulation development, and multi-location field trials, L. fusiformis may represent a promising candidate for development as a biocontrol agent.