Farnesol as a Multifunctional Regulator of Fungal Biology: Mechanisms and Significance

Farnesol is a small isoprenoid metabolite that has emerged as a key regulator of fungal biology beyond its original identification as a quorum-sensing molecule in Candida albicans. This review examines farnesol across pathogenic and non-pathogenic fungi, emphasizing its roles in morphogenesis, biofilm development, stress adaptation, membrane-associated physiology, and ecological interaction. In pathogenic fungi, farnesol modulates virulence-related traits, antifungal susceptibility, and host interaction, while in non-pathogenic systems, it influences growth, differentiation, and metabolic balance. Evidence from Saccharomyces cerevisiae, Trichoderma, Candidozyma auris (formerly known as Candida auris), and other fungi highlights the context-dependent nature of its effects. We also discuss farnesol biosynthesis, secretion, and the apparent absence of canonical salvage pathways in fungi. Together, these findings support a broader view of farnesol as a multifunctional fungal metabolite that links signaling with metabolism. Understanding its diverse biological roles may clarify fungal evolution and inform future strategies targeting fungal persistence, adaptation, and antifungal tolerance.