Food-borne Bacillus species are often associated with postharvest fruit and vegetables, and are a common cause of food poisoning. In this work, melatonin was found to inhibit the growth of food-borne Bacillus species, including B. cereus, B. licheniformis and B. subtilis, on cherry tomatoes. This result was attributed to two complementary effects. On one side, melatonin showed antibacterial activity to B. subtilis, inhibiting cell division and oxidative phosphorylation, and reducing swimming motility and biofilm formation. On the other side, melatonin enhanced the antioxidant capacity of cherry tomatoes, and induced the biosynthesis of phenolics and ethylene, and the overexpression of pathogenesis-related genes PT16 and PR1b1. The defence response was only observed in the presence of both B. subtilis and melatonin, but not in the single treatments. Although melatonin was known to induce disease resistance in fruit in the presence of necrotrophic pathogens, this is the first report of melatonin inducing fruit defence after treatment with a non-necrotrophic bacterium. Collectively, the application of melatonin for the control of food-borne Bacillus pathogens was explored for the first time, revealing a new potential application of melatonin in postharvest products.

食源性芽孢杆菌通常与收获后的水果和蔬菜有关，并且是食物中毒的常见原因。在这项工作中，发现褪黑激素可以抑制樱桃番茄上食源性芽孢杆菌属的生长，包括蜡状芽孢杆菌、地衣芽孢杆菌和枯草芽孢杆菌。这一结果归因于两种互补效应。一方面，褪黑激素对枯草芽孢杆菌表现出抗菌活性，抑制细胞分裂和氧化磷酸化，并减少游泳运动和生物膜形成。另一方面，褪黑激素增强了樱桃番茄的抗氧化能力，诱导了酚类物质和乙烯的生物合成，以及致病相关基因PT16和PR1b1的过度表达。防御反应仅在枯草芽孢杆菌和褪黑激素同时存在时观察到，但在单一处理中未观察到。尽管已知褪黑激素在存在坏死性营养病原体的情况下诱导水果抗病性，但这是首次报道褪黑激素在用非坏死性营养细菌处理后诱导水果防御。总体而言，褪黑激素在控制食源性芽孢杆菌中的应用 首次探索了病原体，揭示了褪黑激素在采后产品中的新潜在应用。