Volatile organic compounds from Meyerozyma guilliermondii JY19 trigger apoptosis-like cell death in Botrytis cinerea and control postharvest gray mold of ginseng berries

Gray mold caused by Botrytis cinerea severely compromises the postharvest value of ginseng berries. We assessed the endophytic yeast Meyerozyma guilliermondii JY19 as a green control and delineated a VOC-mediated mode of action. JY19 inhibited B. cinerea in vitro in diffusible-metabolite, cell-free supernatant, and sealed double-plate VOC assays. Scanning electron microscopy revealed hyphal surface collapse and fissures. VOC exposure induced reactive oxygen species and programmed cell death in conidia based on DCFH-DA staining, Annexin V–FITC/PI imaging, and flow cytometry. HS-SPME–GC–MS profiling identified a characteristic VOC repertoire; 3,5-diethyl-2-methylpyrazine, 4-methyl-2-pentanol, and trans-ocimenol showed dose-dependent inhibition with IC₅₀ values of 9.5, 23.1, and 26.7 μL L⁻¹ , respectively, whereas 1-hydroxy-2-propanone was inactive. RNA-seq showed concerted repression of nutrient-transport systems and xenobiotic detoxification (including multiple cytochrome P450s), together with attenuation of sphingolipid and glycosphingolipid pathways and MAPK signaling; oxidative phosphorylation was upregulated, consistent with metabolic compensation under VOC. In vivo , JY19 VOCs delayed disease onset and reduced lesion area by 79.3 %, 77.3 %, and 39.3 % on days 1, 2, and 3, respectively, thereby limiting decay under high humidity. These multi-level data support a mode-of-action model in which JY19 VOCs compromise membrane integrity and nutrient acquisition, trigger ROS-driven programmed cell death, and constrain fungal growth and virulence. To our knowledge, this is the first integrated in vitro , cytological, transcriptomic, and in vivo evaluation of VOC-based gray mold control on ginseng berries, positioning JY19 and its dominant VOCs as residue-lean biofumigation leads for postharvest management. • Yeast VOCs from M. guilliermondii JY19 control gray mold on ginseng berries. • Key antifungal volatiles include 3,5-diethyl-2-methylpyrazine and trans-ocimenol. • VOCs trigger ROS-mediated cell death and hyphal damage in B. cinerea . • Transcriptomics reveals suppressed transport and MAPK signaling genes. • VOCs offer a residue-free biofumigation strategy for postharvest preservation.