Multi-omics dissection of Trametes versicolor CS05-mediated defense enhancement in Crocus sativus under Fusarium oxysporum corm rot stress

Saffron ( Crocus sativus ) is a high-value crop prized in culinary and pharmaceutical applications for its nutritional and therapeutic properties. However, corm rot caused by Fusarium oxysporum severely compromises yield and quality. Here, we isolated F. oxysporum strain CSP01 from diseased corms and confirmed it as the primary causal agent. Five endophytic fungi—CS05 ( Trametes versicolor ), CS06 ( Bjerkandera adusta ), CS07 ( Phlebia acerina ), CS33 ( Penicillium sp. ), and CS65 ( Trichoderma sp. )—were screened for biocontrol efficacy against CSP01. CS05 showed the strongest suppression, achieving a 75.97% control rate and outperforming the positive controls Mortierella alpina and Trichoderma harzianum. To elucidate CS05-mediated protection, we integrated transcriptomic, proteomic, and metabolomic analyses. Transcriptome profiling revealed robust induction of host defense genes following CS05 treatment, particularly in phenylpropanoid biosynthesis ( PAL2, 4CL1, CCR4 ), jasmonic acid (JA) signaling ( COI1 ), and hydrogen peroxide (H2O2) metabolism ( CAT1 ). Metabolomic analysis identified 461 differentially accumulated metabolites in CS05-treated corms; notably, L -tyrosine, coniferin, and p-coumaraldehyde were enriched within phenylpropanoid pathways and associated with enhanced resistance. qRT-PCR and enzyme activity assays validated the involvement of PAL2, 4CL1 , and CCR4 in phenylpropanoid biosynthesis. Phytohormone measurements showed significantly elevated JA in CS05-treated corms (12.774 pmol/L) relative to pathogen-only corms (7.773 pmol/L). Oxidative stress assessments indicated that H2O2 in infected corms peaked at day 30 (41.189 mmol·g-1 protein); at day 24, infected corms contained 20.904 mmol·g-1 protein versus 16.760 mmol·g-1 protein in CS05-treated corms, demonstrating mitigation of excessive reactive oxygen species. Collectively, these results show that T. versicolor CS05 enhances saffron resistance to corm rot by coordinating phenylpropanoid pathway activation, amplifying JA signaling, and improving H2O2 detoxification. This study provides the first evidence that T. versicolor CS05 is an effective, eco-friendly biocontrol agent for saffron corm rot and offers mechanistic insight into endophyte-driven plant defense, supporting its potential for sustainable disease management.