Work

Bacillus velezensis 7-A as a Biocontrol Agent Against Fusarium verticillioides, the Causal Agent of Rice Sheath Rot Disease

Year: 2025

Type: article

Abstract: Rice sheath rot has progressively developed into a growing threat to global rice production, particularly in intensively managed systems conducive to disease development. Therefore, accurate identification of causal pathogen and the development of sustainable management strategies represent urgent scientific requirements. In this study, we isolated the causal organism of rice sheath rot from infected rice tissues and identified it as Fusarium verticillioides with a combined phylogenetic approach targeting multiple genetic loci. In this study, eight endophytic bacterial strains were recovered from healthy rice root systems. The results showed that strain 7-A exhibited the showed the strongest antifungal activity against antifungal activity against F. verticillioides. This strain demonstrated broad-spectrum antifungal activity, with inhibition rates ranging from 54.8% to 71.8%. Phylogenetic analysis based on 16S rDNA and gyrB gene sequences identified it as Bacillus velezensis. Further characterization revealed that strain 7-A is capable of secreting protease and synthesizing siderophores. The filtered liquid from sterile fermentationmarkedly inhibited the growth of mycelium in F. verticillioides and induced marked morphological abnormalities. Liquid LC-MS analysis identified multiple antifungal active substances, including camphor, ginkgolides B, salicin, cinnamic acid, hydroxygenkwanin, stearamide, β-carotene, and others. Greenhouse experiments demonstrated that the fermentation broth of strain 7-A effectively suppressed the occurrence of rice sheath rot, achieving a relative control efficacy of 61.3%, which is comparable to that of a 10% carbendazim water dispersible granule (WDG). These findings provide preliminary insights for its potential application in integrated and sustainable disease management programs.

Source: Microorganisms

DOI: 10.3390/microorganisms13112511