[en] Surfactin (SRF) is a lipopeptide produced by plant beneficial bacilli able to stimulate plant immunity, making it an interesting candidate as biocontrol agent. Our previous results have shown an atypical sensing mechanism mediated by its interaction with the lipid fraction of the plant plasma membrane (PPM) rather than a perception through protein pattern recognition receptors, the common description of elicitor perception in plants.
Our recent results have suggested that this insertion of SRF into PPM lipids disturbs membrane physical properties and consequently activates PPM-located mechanosensitive ionic channels, proteins sensitive to membrane mechanics. Nevertheless, the description of immune stimulation through this process is still elusive.
To characterise this new mechanism, we compared immune responses triggered by SRF with the one triggered by the well described elicitor flagellin. Comparison of calcium responses, intracellular ROS production and change of membrane fluidity, a parameter affecting membrane mechanics, revealed that SRF immune stimulation presents specific features compared to a conventional elicitor.
Altogether, our results shed light on new aspects of plant immune stimulation by beneficial bacterial molecules.
