Ethyl p-coumarate exerts antifungal activity in vitro and in vivo against fruit Alternaria alternata via membrane-targeted mechanism
Ethyl p-coumarate exerts antifungal activity in vitro and in vivo against fruit Alternaria alternata via membrane-targeted mechanism
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DOI：
10.1016/j.ijfoodmicro.2018.04.024
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发表时间：
2018-08-02
影响因子：
5.4
通讯作者：
Cao, Jiankang
中科院分区：
文献类型：
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作者：
Li, Wusun;Yuan, Shuzhi;Cao, Jiankang
真菌链格孢 (Alternaria alternata) 会导致黑斑腐病污染食品，并因产生霉菌毒素而导致食品安全问题。特别是，链格孢菌可以感染许多新鲜水果和蔬菜，并在储存和加工过程中导致严重的采后腐烂。在采后病害管理中使用植物源产品可能是传统化学杀菌剂的可接受的替代品。本研究的目的是评估对香豆酸乙酯 (EpCA) 在体外和体内对链格孢菌的抗真菌活性，并确定其潜在机制。结果表明，EpCA对A. alternata菌丝体的体外生长表现出明显的抗真菌活性，半抑制浓度为176.8 μg/mL。 EpCA 以剂量依赖性方式抑制病原体的孢子萌发。此外，体内试验证实，100和800μg/mL EpCA均显着减少了由A. alternata引起的枣果黑斑腐病的发展。 EpCA处理增加了质膜的通透性，因为在培养过程中链格孢的细胞间电解质、可溶性蛋白质和糖发生大量渗漏。 EpCA 处理还导致碘化丙啶（一种结合细胞核 DNA 的荧光染料）流入受影响孢子的数量增加，表明质膜完整性被破坏。超微结构观察进一步证明EpCA对链格孢质膜和形态造成损伤，导致病原菌孢子和菌丝体变形、凹陷、皱缩。此外，通过共焦激光扫描显微镜进行的荧光测定证实，EpCA处理诱导了链格孢孢子内源性活性氧（ROS）的形成，并且在较高浓度的EpCA下ROS的积累更强且更稳定。因此，细胞膜和器官可能会发生严重的氧化损伤，EpCA 处理的病原体严重发生脂质过氧化就证明了这一点。综上所述，这些结果表明 EpCA 通过膜靶向机制发挥抗真菌活性，它将成为控制水果采后病害的有希望的候选者。
The fungus Alternaria alternata can cause food contamination by black spot rot and food safety issues due to the production of mycotoxins. In particular, A. alternata can infect many fresh fruits and vegetables and lead to considerable postharvest decay during storage and processing. The use of plant-derived products in postharvest disease management may be an acceptable alternative to traditional chemical fungicides. The aim of this study was to assess the antifungal activity of ethyl p-coumarate (EpCA) against Alternaria alternata in vitro and in vivo, and to determine the underlying mechanism. Results indicated that EpCA exhibited pronounced antifungal activity against in vitro mycelial growth of A. alternata, with half-inhibition concentration of 176.8 mu g/mL. Spore germination of the pathogen was inhibited by EpCA in a dose-dependent manner. Moreover, in vivo test confirmed that both 100 and 800 mu g/mL EpCA significantly reduced disease development of black spot rot in jujube fruit caused by A. alternata. The EpCA treatments increased plasma membrane permeability as great leakage of intercellular electrolytes, soluble proteins and sugars of A. alternata occurred during incubation. The EpCA treatments also caused increase of the influx of propidium iodide, a fluorescence dye binding nucleus DNA, into the affected spores, indicating the disrupted plasma membrane integrity. Observations of ultrastructure further evidenced the damage to plasma membrane and morphology of A. alternata caused by EpCA, which resulted in distortion, sunken and shrivelled of spores and mycelia of the pathogen. In addition, fluorometric assay by confocal laser scanning microscopy confirmed that the EpCA treatments induced endogenous reactive oxygen species (ROS) formation in the spores of A. alternata, with stronger and more stable accumulation of ROS at higher concentration of EpCA. Therefore, heavy oxidative damage to cellular membranes and organdies might happen as demonstrated by the severe occurrence of lipid peroxidation of the pathogen treated with EpCA. Taken together, these results indicated that EpCA exerts antifungal activity via membrane-targeted mechanism and it would be a promising candidate to control postharvest diseases of fruits.