6-pentyl-2H-pyran-2-one: from a fungal volatile metabolite to an ecological signaling hub for sustainable crop protection

6-Pentyl-2H-pyran-2-one (6-PP) is a characteristic volatile secondary metabolite produced by Trichoderma species and was initially studied for its coconut-like odor and antifungal activity. Recent studies have revealed that 6-PP has broader roles in fungal ecology, influencing pathogen interactions, plant responses, and associated microbial communities. Here, we summarize recent advances in 6-PP biology, focusing on four aspects: the evolution of its biosynthetic model, the regulation of its production, its ecological functions, and its potential applications in crop protection. The discovery of the Pks1-mediated pathway has revised previous views based mainly on fatty acid metabolism and provided genetic evidence for 6-PP biosynthesis. We further discuss how environmental signals, intracellular signaling pathways, transcriptional regulators, chromatin modification, and metabolic states collectively influence 6-PP production. At the ecological level, 6-PP acts as a signaling molecule that affects pathogen fitness, plant growth and defense responses, and plant-associated microbiome assembly. Finally, we highlight strategies for translating 6-PP biology into agricultural applications through strain engineering, controlled-release formulations, and microbial consortium-based biocontrol. Key challenges include elucidating downstream biosynthetic steps, identifying plant perception mechanisms, clarifying the ecological effects of 6-PP on microbial communities, and validating its efficacy under field conditions. Addressing these knowledge gaps will advance our understanding of 6-PP as a potential ecological signaling molecule and support the development of sustainable crop protection strategies.