It is fascinating how plants identify the microorganisms they encounter, choosing to collaborate with some while launching vigorous defenses to repel others. The key to combating invasive pathogens lies in swiftly recognizing them as threats. Once the pathogen population becomes too large, activating defense mechanisms is often futile. Therefore, plants must determine whether a microorganism is a pathogen early on, when information is scarce. Under laboratory conditions, it has been shown that plants recognize pathogens within minutes to hours. During evolution, did plants prioritize symbiosis to secure nutrients, or did they first develop defense mechanisms to protect themselves from pathogens? While this life-or-death question remains largely unanswered, the text below summarizes the insights uncovered thus far.