Evaluación integrada de cepas de Bacillus spp. para la supresión de Ralstonia solanacearum raza 2 y la promoción del crecimiento vegetal

Abstract

Ralstonia solanacearum race 2 is a soil-borne vascular pathogen that constrains the production of susceptible crops and requires effective biological management strategies. This study evaluated the potential of Bacillus sp. strains to suppress the pathogen and promote the growth of banana vitroplants. Antagonistic activity was determined through dual culture assays in vitro. For the plant assay, banana vitroplants acclimatized for four weeks were individually established in pots containing 750 g of sterilized soil inoculated with R. solanacearum race 2. After 24 h, 0.5 mL of Bacillus sp. suspensions adjusted to approximately 1 × 10⁸ CFU mL⁻¹ were applied. In vitro inhibition, residual pathogen population in soil, root length, dry biomass, and disease incidence were evaluated. Data were analyzed using ANOVA or Kruskal–Wallis tests, according to assumption compliance, and integrated through principal component analysis. Strain C2 showed the highest in vitro inhibition (57.4 ± 11.1%), reduced the residual population of R. solanacearum to 23.1 CFU g⁻¹ of soil, compared with 186.3 CFU g⁻¹ in the control, and decreased disease incidence to 13.9%, compared with 56.8% in the control. In addition, C2 promoted the greatest root development (30.4 cm) and dry biomass accumulation (55.2 g). The multivariate analysis explained 84.4% of the total variation and clearly separated C2 from the control. In conclusion, C2 showed the most consistent profile for suppressing R. solanacearum race 2 and promoting plant growth, making it a promising candidate for further biocontrol evaluations under greenhouse and field conditions