Olmedo Gabriela M, Cerioni Luciana, González María M, Cabrerizo Franco M, Volentini Sabrina I, Rapisarda Viviana A
INSIBIO (CONICET, UNT), Instituto de Química Biológica "Dr. Bernabé Bloj", Facultad de Bioquímica, Química y Farmacia, UNT Tucumán, Argentina.
IIB-INTECH - UNSAM-CONICET Buenos Aires, Argentina.
Front Microbiol. 2017 Mar 7;8:347. doi: 10.3389/fmicb.2017.00347. eCollection 2017.
Phytopathogenic fungi responsible for post-harvest diseases on fruit and vegetables cause important economic losses. We have previously reported that harmol (1-methyl-9H-pyrido[3,4-b]indol-7-ol) is active against the causal agents of green and gray molds and , respectively. Here, antifungal activity of harmol was characterized in terms of pH dependency and conidial targets; also photodynamic effects of UVA irradiation on the antimicrobial action were evaluated. Harmol was able to inhibit the growth of both post-harvest fungal disease agents only in acidic conditions (pH 5), when it was found in its protonated form. Conidia treated with harmol exhibited membrane integrity loss, cell wall disruption, and cytoplasm disorganization. All these deleterious effects were more evident for in comparison to . When conidial suspensions were irradiated with UVA in the presence of harmol, antimicrobial activity against both pathogens was enhanced, compared to non-irradiated conditions. exhibited a high intracellular production of reactive oxygen species (ROS) when was incubated with harmol in irradiated and non-irradiated treatments. showed a significant increase in ROS accumulation only when treated with photoexcited harmol. The present work contributes to unravel the antifungal activity of harmol and its photoexcited counterpart against phytopathogenic conidia, focusing on ROS accumulation which could account for damage on different cellular targets.
导致水果和蔬菜采后病害的植物病原真菌会造成重大经济损失。我们之前报道过哈尔莫（1-甲基-9H-吡啶并[3,4-b]吲哚-7-醇）分别对绿霉病和灰霉病的病原体具有活性。在此，对哈尔莫的抗真菌活性进行了pH依赖性和分生孢子靶点方面的表征；还评估了紫外线A（UVA）照射对抗菌作用的光动力效应。仅在酸性条件（pH 5）下，当哈尔莫以质子化形式存在时，它才能抑制两种采后真菌病原体的生长。用哈尔莫处理的分生孢子表现出膜完整性丧失、细胞壁破坏和细胞质紊乱。与[未提及的对照物]相比，所有这些有害影响对[提及的病原体]更为明显。当在存在哈尔莫的情况下用UVA照射分生孢子悬浮液时，与未照射条件相比，对两种病原体的抗菌活性增强。在照射和未照射处理中，当[提及的病原体]与哈尔莫一起孵育时，其细胞内活性氧（ROS）的产生量较高。只有在用光激发的哈尔莫处理时，[另一种提及的病原体]才显示出ROS积累显著增加。本研究有助于阐明哈尔莫及其光激发对应物对植物病原分生孢子的抗真菌活性，重点关注可能导致不同细胞靶点受损的ROS积累。
