食品科学 ›› 2020, Vol. 41 ›› Issue (19): 221-229.doi: 10.7506/spkx1002-6630-20190824-258

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ε-聚赖氨酸对柑橘酸腐菌的抑菌活性及作用机制

肖媛,潘兆平,尹春晓,苏瑾,胡筱,朱向荣,单杨,付复华   

  1. (1.湖南大学研究生院隆平分院,湖南?长沙 410125;2.湖南省农业科学院农产品加工研究所,湖南?长沙 410125;3.果蔬贮藏加工与质量安全湖南省重点实验室,湖南?长沙 410125)
  • 出版日期:2020-10-15 发布日期:2020-10-23
  • 基金资助:
    “十三五”国家重点研发计划重点专项(2017YFD0401303);长株潭国家自主创新示范区专项(2018XK2006); 湖南省农业科学院科技创新项目(2018ZD04-1);湖南省水果产业技术体系项目(湘农发(2019)105号)

Antifungal Activity and Mechanism of ε-Polylysine against Geotrichum citri-aurantii

Xiao Yuan, PAN Zhaoping, Yin Chunxiao,, Su Jin,, hu xiao,, Zhu Xiangrong, Shan Yang, Fu Fuhua   

  1. (1. Longping Branch Graduate School, Hunan University, Changsha 410125, China; 2. Hunan Agricultural Product Processing Institute, Hunan Academy of Agricultural Sciences, Changsha 410125, China; 3. Hunan Province Key Laboratory of Fruits and Vegetables Storage, Processing, Quality and Safety, Changsha 410125, China)
  • Online:2020-10-15 Published:2020-10-23

摘要: ε-聚赖氨酸(ε-polylysine,ε-PL)是一种高安全性、可生物降解的天然食品防腐剂,对环境和人体健康无毒性。为探究ε-PL对柑橘酸腐菌(Geotrichum citri-aurantii)的抑菌活性,并分析其抑菌作用机制,本实验测定ε-PL处理对柑橘酸腐菌的菌丝体生长抑制率及孢子萌发抑制率,ε-PL作用下的胞外相对电导率、A260 nm的变化,并采用激光共聚焦显微镜与扫描电子显微镜观察ε-PL处理对细胞膜完整性及菌丝体形态的影响。结果表明:ε-PL对柑橘酸腐菌的最小抑菌浓度(minimum inhibitory concentration,MIC)为400 mg/L,对菌丝生长和孢子萌发抑制的半最大效应浓度分别为128.79 mg/L和214.77 mg/L;质量浓度为1 600、3 200、6 400 mg/L的ε-PL处理可显著降低柑橘果实酸腐病的损伤接种发病率和病斑直径(P<0.05);经1×MIC和2×MIC的ε-PL处理后的柑橘酸腐菌胞外相对电导率、A260 nm和红色荧光强度显著上升(P<0.05),表明其细胞膜通透性增加,核酸等胞内物质外渗流出,细胞膜完整性遭到破坏;经ε-PL处理后柑橘酸腐菌菌丝体发生了褶皱变形、断裂。因此,ε-PL通过破坏柑橘酸腐菌的细胞膜结构,造成内容物外渗,使菌丝体形态结构畸变与孢子萌发受阻,进而抑制了菌体细胞的生长繁殖。

关键词: 柑橘酸腐菌;ε-聚赖氨酸;抑菌活性;细胞膜;抑菌机制

Abstract: Epsilon-polylysine (ε-PL) is a safe and biodegradable natural food preservative without any adverse effects on the environment or human health. The antifungal activity and mechanism of ε-PL on Geotrichum citri-aurantii were investigated in this study. The mycelium growth inhibition rate, spore germination inhibition rate, extracellular relative electric conductivity and absorbance at 260 nm (A260 nm) value of Geotrichum citri-aurantii were determined after being treated with ε-PL. Additionally, laser scanning confocal microscopy (LSCM) and scanning electron microscopy (SEM) were used to study the effects of ε-PL treatment on the cell membrane integrity and mycelium morphology of Geotrichum citri-aurantii, respectively. The results showed that the minimum inhibitory concentration (MIC) was 400 mg/L, and the half maximal effective concentration (EC50) for inhibiting mycelium growth and spore germination were 128.79 and 214.77 mg/L, respectively. When used at concentrations of 1 600, 3 200 and 6 400 mg/L, ε-PL significantly lowered the incidence of sour rot and lesion diameter in citrus fruit with stab inoculation compared to the control fruit (P < 0.05). After being treated with ε-PL at 1 × MIC and 2 × MIC, extracellular relative electric conductivity, A260 nm and fluorescence intensity were significantly increased relative to the control group (P < 0.05), which indicated increased cell membrane permeability, thereby leading to the leakage of intracellular components such as nucleic acids and causing damage to the integrity of the membrane. Furthermore, ε-PL treatment induced severe distortion and disruption of the mycelia of Geotrichum citri-aurantii. Therefore, ε-PL can destroy the structure of the cell membrane, causing the leaking of intracellular contents and distortion of the mycelia, retarding spore germination, and thus inhibiting the growth and development of Geotrichum citri-aurantii.

Key words: Geotrichum citri-aurantii; ε-polylysine; antifungal activity; cell membrane; antifungal mechanism

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