Plant prebiotica: de rol van de fyllosfeer tijdens fructaan priming als verdediging tegen grauwe schimmel (Botrytis cinerea) in sla (Lactuca sativa)

Some natural compounds are known to enhance the immune system of plants by a process called priming, which is comparable to the immune-stimulating properties of vaccines in humans. Fructose polymers termed fructans have recently been shown to act as priming agents protecting lettuce (Lactuca sativa) against grey mold (Botrytis cinerea) when sprayed onto the leaf surface, however their method of action remains unknown. Fructans may be recognized by plant receptors that trigger cellular signaling and ultimately the activation of defense responses. However, plant receptors able to recognize fructans are not yet identified. In humans, fructans act as prebiotics, meaning that they stimulate the growth of healthpromoting microorganisms in the gastrointestinal tract. We propose that fructans could act in a similar way in plants, shifting the balance of pathogenic and beneficial plant-associated microorganisms towards a more beneficial state, ultimately contributing to disease control. This second hypothesis will be the focus of this project and will be investigated through culture-dependent and -independent approaches after isolation of microorganisms living in the lettuce leaf environment (the so-called phyllosphere). Extending the prebiotic concept to horticulture and agriculture represents a novel strategy in sustainable plant protection.