Bacterial plant diseases challenge agricultural production. Chemical-based management strategies, which are commonly used to control bacterial plant diseases, have limited effectiveness and often promote emergence of resistant bacterial strains. Consequently, there is increasing interest in development of alternative, sustainable disease management strategies to deal with this type of diseases, including biological control. Here we evaluated the potential of Paenibacillus dendritiformis C454 as a biocontrol agent against key bacterial phytopathogens. In vitro assays revealed broad-spectrum antagonism against both gram negative and gram positive phytopathogens, mediated by diffusible metabolites. In contrast, no detectable antagonistic activity was detected for this strain against fungi or oomycete. Foliar pretreatment with P. dendritiformis C454 reduced disease severity and pathogen titers in melon and watermelon plants inoculated with Paracidovorax citrulli, as well as in tomato and Arabidopsis inoculated with Pseudomonas syringae pv. tomato. In nursery-tray experiments with melon and tomato, P. dendritiformis C454 suppressed secondary disease spread, performing comparably to the copper-based commercial bactericide Kocide. To address potential ecological risks, we examined the effects of P. dendritiformis C454 spores on adult honey bees (Apis mellifera) and found no impact on their survival or learning performance. Overall, our findings highlight the strong potential of P. dendritiformis C454 as an environment-friendly tool for managing bacterial diseases, particularly in nursery and greenhouse production systems.
Livneh et al. (Mon,) studied this question.