Figure 7.

Schematic representation of the mechanisms of action of B. subtilis UMAF6639 against the cucurbit powdery mildew fungus P. fusca. UMAF6639 acts in the phyllosphere through direct antagonism mediated by the production of iturin (itu) and fengycin (fen) antifungal lipopeptides. In the rhizosphere, UMAF6639 acts by activation of JA- and SA-dependent defence responses, in which surfactin (srf) is an elicitor. These defence responses include the production of reactive oxygen species (ROS) and cell wall deposits (cell wall reinforcement), which are activated after pathogen attack (priming).