Volatile organic compounds from Lysinibacillus fusiformis: Dual-action of grey mold inhibition and postharvest quality preservation in cherry tomatoes.

Postharvest quality deterioration and fungal disease severely reduce the commercial value of cherry tomatoes, while traditional chemical preservation approaches raise food safety and environmental risks. Microbial volatile organic compounds (VOCs) are regarded as eco-friendly and efficient postharvest preservation alternatives. This study systematically investigated the effects and underlying molecular mechanisms of VOCs produced by Lysinibacillus fusiformis in maintaining postharvest quality and inducing disease resistance in cherry tomatoes. L. fusiformis VOCs fumigation significantly suppressed fruit decay, reduced weight loss, and maintained firmness and pigment degradation. Exposure to VOCs alleviated postharvest membrane oxidative damage, as evidenced by reduced relative electrolyte leakage and malondialdehyde (MDA) accumulation. In terms of nutritional quality, VOCs exposure promoted the accumulation of vitamin C, total phenolics, and lycopene, while preventing the degradation of soluble sugars (sucrose, fructose, glucose) and organic acids (malic acid, citric acid, succinic acid). This was accompanied by marked activation of antioxidant defense system, evidenced by sustained activities of SOD, POD, CAT, and APX. Transcriptomic analysis further revealed that VOCs improved fruit storability and disease resistance by upregulating genes enriched in plant-pathogen interaction, phenylpropanoid biosynthesis, and plant hormone signal transduction pathways. In addition, VOCs exerted strong antifungal activity against Botrytis cinerea both in vitro and in vivo. GC-MS identified 49 distinct volatiles, with five key compounds (isobutyl alcohol, cyclopentanone, 2-phenylethanol, methyl 2-methylbutyrate, methyl isovalerate) exhibited strong antifungal effects. Overall, these findings highlight L. fusiformis VOCs as a viable, sustainable postharvest biofumigant for controlling grey mold and extending tomato shelf life.