Lipid droplets at the interface of plant defense and pathogen exploitation

Abstract

Lipid droplets (LDs) are increasingly recognized as dynamic organelles involved in lipid metabolism, organelle communication, and stress responses. During plant-pathogen interactions, LDs undergo extensive remodeling, including changes in abundance, lipid composition, intracellular distribution, and associated proteins. Recent studies indicate that bacterial and fungal infections consistently promote LD accumulation and proteome reprogramming. This supports emerging roles for LDs in antimicrobial metabolism, defense signaling, membrane remodeling, and cellular homeostasis. However, these organelles may also provide metabolic resources that pathogens exploit to promote infection. Beyond bacterial and fungal pathogens, recent evidence suggests that plant viruses could also manipulate LD biology to facilitate replication compartment biogenesis, membrane remodeling, and potentially virus movement. In this review, we summarize current knowledge on LD dynamics during plant-pathogen interactions, compare LD responses across different pathogen lifestyles, and discuss the dual roles of LDs in plant immunity. Finally, we propose a conceptual framework in which LD functions may support host defense, be actively manipulated by pathogens, thereby providing a broader perspective on the diverse roles of LDs in determining disease outcomes.