Plant -acylethanolamines play a crucial role in defense and its variation in response to elevated CO and temperature in tomato.

The ubiquitous lipid-derived molecules acylethanolamines (NAEs) have multiple immune functions in mammals, but their roles and mechanisms in plant defense response during changing environment remain largely unclear. Here, we found that exogenous NAE18:0 and NAE18:2 promoted defense against the necrotrophic pathogen but suppressed defense to the hemi-biotrophic pathogen pv. () DC3000 in tomato. The knocking-down and overexpression function analysis of the pathogen-responsive NAE synthetic gene () and hydrolytic gene () revealed that the NAE pathway is crucial for plant defense response. Using exogenous applications and SA-abolished NahG plants, we unveiled the antagonistic relationship between NAE and SA in plant defense response. Elevated CO and temperature significantly changed the NAE pathway in response to pathogens, while inhibition of the NAE pathway led to the alternation of environment-mediated defense variations against DC3000 in tomato, indicating that NAE pathway is associated with plant defense variations in response to elevated CO and temperature. The results herein reveal a new function of NAE in plant defense, and its involvement in environment-mediated defense variation in tomato. These findings shed light on the NAE-based plant defense, which may have relevance to crop disease management in future changing climate.