prevents infection by inhibiting pathogen growth and eliciting plant immune responses.

The pathogen causes enormous damage to important agricultural plants. This group of filamentous pathogens is phylogenetically distant from fungi, making them difficult to control by most chemical fungicides. OH11 (OH11) is a biocontrol bacterium that secretes HSAF (Heat-Stable Antifungal Factor) as a broad-spectrum antifungal weapon. Here, we showed that OH11 could also control a variety of plant diseases caused by three major oomycetes (, and ). We provided abundant evidence to prove that OH11 protected host plants from pathogen infection by inhibiting mycelial growth, digesting cysts, suppressing cyst germination, and eliciting plant immune responses. Interestingly, the former two processes required the presence of HSAF, while the latter two did not. This suggested that could prevent infection multiple previously unknown mechanisms. Therefore, this study showed that could serve as a promising alternative resource for promoting plant resistance to multiple pathogens.