3rd Edition Of Plant Science and Molecular Biology World Conference 2026

Abstract

Rhizoctonia solani represents a pervasive soil-borne phytopathogen responsible for substantial yield attenuation in economically strategic crops globally. This study elucidates the development of a chitosan-alginate microencapsulation system designed to augment the environmental resilience and antagonistic potential of Bacillus subtilis against R. solani. Utilizing the ionotropic gelation technique, microcapsules were synthesized to evaluate the synergistic effects of chitosan molecular weight and capsule geomorphology on bacterial growth kinetics and biocontrol efficacy. Empirical data demonstrated that the bio-polymeric scaffolding successfully sustained high bacterial viability, facilitating the formation of dense micro-colonies within a 72-hour incubation period. Notably, microcapsules with a diameter of 100 μm exhibited significantly enhanced proliferation rates, an observation attributed to optimized interfacial nutrient mass transfer and efficient gas exchange dynamics. Scanning Electron Microscopy (SEM) characterization corroborated a highly porous architectural framework, which functions as both a protective niche for bacterial retention and a controlled-release matrix for antifungal secondary metabolites. In-vitro bioassays indicated that the encapsulated B. subtilis effectively suppressed the radial mycelial expansion of R. solani following a 7-day co-cultivation period. Conversely, control treatments employing vacant microcapsules exhibited rapid colonization by the pathogen, confirming that inhibitory effects are strictly secondary to the metabolic activity of the encapsulated endophytes. Furthermore, the persistence of antifungal efficacy across varying chitosan molecular weights suggests that the biocontrol mechanism is primarily mediated by sustained metabolic secretions. These findings substantiate the chitosan-alginate platform as a highly biocompatible and efficacious delivery vehicle. This technology provides a robust, ecologically sustainable alternative to synthetic fungicides, offering a scalable strategy for the integrated management of Rhizoctonia-induced diseases in contemporary precision agriculture.