Shifting the paradigm in Vanilla odorata micropropagation: Trichoderma spp. as a strategic agent for biocontrol and biostimulation

ABSTRACT Vanilla (Vanilla spp., Orchidaceae) is one of the most economically valuable tropical crops, yet commercial production relies almost exclusively on V. planifolia, creating genetic vulnerability to vascular diseases, particularly Fusarium oxysporum f. sp. vanillae (Fov). Vanilla odorata represents a strategic genetic resource, but propagation faces critical bottlenecks: Low multiplication efficiency, fungal susceptibility, and > 60% acclimatization mortality. This review synthesizes evidence (2010-2025) on Trichoderma spp. as dual-function agents in micropropagation: Biocontrol and plant growth promotion (PGP). Analysis of 14 studies shows selected strains (T. harzianum, T. virens, T. asperellum) inhibit Fov by > 80% via mycoparasitism/antibiosis, increasing ex vitro survival 1.6-fold and biomass 3.6-fold vs. controls. Mechanisms include nutrient solubilization, auxin production, and induced systemic resistance (ISR) activation. Crucially, unlike conventional chemical disinfection (ethanol, hypochlorite, antibiotics), which often fails against endophytic contaminants and risks explant damage; biotization enhances viability while reducing reliance on synthetic inputs. Though strain-specific and requiring standardization, its potential economic benefit lies not in direct cost-cutting, but in mitigating seedling loss and acclimatization mortality, a costly phase. Integration with temporary immersion systems or Ag nanoparticles offers a sustainable, scalable protocol. This marks a paradigm shift from absolute asepsis toward managed beneficial microbiota, addressing key technical-practical challenges in tropical crop biotechnology. Implementing biotized protocols is essential for valorizing V. odorata germplasm and ensuring long-term sustainability of natural vanilla production.