Quorum Signaling Molecules: Interactions Between Plants and Associated Pathogens

The morphogenesis and defense evolution of plants are intricately linked to soil microbial community dynamics, where beneficial and pathogenic bacteria regulate ecosystem stability through chemical signaling. A microbial communication mechanism known as quorum sensing (QS), which affects population density, virulence, and biofilm formation, substantially impacts plant development and immune responses. However, plants have developed strategies to detect and manipulate QS signals, enabling bidirectional interactions that influence both plant physiology and the balance of the microbiome. In this review, QS signals from bacteria, fungi, and nematodes are systematically examined, emphasizing their recognition by plant receptors, downstream signaling pathways, and the activation of defense responses. Most significantly, attention is given to the role of fungal and nematode QS molecules in modulating plant microbe interactions. By elucidating these communication networks, we highlight their potential applications in sustainable agriculture, offering novel insights into crop health management and ecosystem resilience.