Abstract
BACKGROUND: Quorum sensing (QS) is a cell-to-cell communication system that enables microbial communities to dynamically regulate their metabolism and physiological activities according to the surrounding cell density. The rumen's diverse microbial ecosystem represents a classic example of host-microbiome symbiosis. Despite significant progress in understanding the composition and function of ruminal microbial communities, the underlying communication mechanisms in the rumen ecosystem remain largely enigmatic. Gaining insight into these regulatory mechanisms is crucial for developing knowledge-based strategies to improve animal productivity, health, and sustainability in ruminant livestock production. AIM OF REVIEW: This review aims to provide an overview of microbial QS communication systems mediated by diverse signaling molecules, including bacterial intraspecies and interspecies QS, fungal QS, and archaeal QS. We conducted a structured review by searching multiple scientific databases, synthesizing data from relevant studies, and critically evaluating the roles of QS systems in microbial communities. This approach ensures a comprehensive analysis of the current understanding of QS mechanisms and their implications for ruminant livestock. Specifically, we elucidate the identification and potential mechanisms of the QS system facilitated by three prevalent signaling molecules (N-acyl homoserine lactones, autoinducing peptides, and autoinducer 2) in ruminants. Recent advances in understanding the effects of QS on microbial fermentation, immune function, biofilm formation, and virulence factor production are summarized in detail, providing a scientific basis for applying QS in ruminant livestock production. KEY SCIENTIFIC CONCEPTS OF REVIEW: The rumen harbors various QS signaling molecules that modulate microbial community dynamics, impacting composition, structure, and function. The versatility of QS allows it to regulate ruminal fermentation and inhibit pathogen growth, thereby improving productivity and reducing disease risk in ruminants. This review synthesizes recent advances in QS mechanisms, crucial for disease prevention, combating antibiotic resistance, and promoting sustainable livestock production. Future research should investigate QS pathways and networks in the rumen microbiome through in vivo experiments and multi-omics analyses to gain a deeper understanding of microbial community regulation.