Singh Vivek Kumar, Upadhyay Ram Sanmukh
Laboratory of Mycopathology and Microbial Technology, Centre of Advanced Study in Botany, Banaras Hindu University, Varanasi, 221005, India.
Bot Stud. 2014 Dec;55(1):66. doi: 10.1186/s40529-014-0066-2. Epub 2014 Aug 27.
Fusaric acid (FA) has been shown to stimulate the rapid development of disease symptoms, such as necrosis and foliar desiccation. In this study, we have evaluated the phytotoxicity of FA on tomato plants (Solanum lycopersicum L.). FA induced necrotic lesions in detached leaves, which are reminiscent of hypersensitive response (HR) lesions induced by plant-pathogen interactions and other abiotic stress factors.
FA-treated tomato leaves exhibited visible necrotic lesion as a result of cell death which was evident by Evans blue staining, enhanced reactive oxygen species (ROS) levels and DNA degradation. Changes in the generation of O and HO as well as the activities of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) were examined in FA-treated tomato leaves. It was observed that FA exposure stimulated oxidative burst in the leaves, resulting in a lasting activation of O and HO production. After first day of FA application, the HO scavenging enzymes CAT and APX showed a strong activity decrease followed by gradual recovery to the control level after 2 and 3 days.
A concomitant increase in ROS production, the down regulation of antioxidative enzymes activities and upregulation of lipid peroxidation were crucial for the onset of cell death. These results suggested that FA-induced damage might result from ROS pathways. Thus, our experiments provide a useful model plant system for research on FA-induced plant cell death.
已表明镰孢菌酸(FA)能刺激疾病症状快速发展,如坏死和叶片干枯。在本研究中,我们评估了FA对番茄植株(番茄)的植物毒性。FA在离体叶片中诱导坏死斑,这让人联想到植物 - 病原体相互作用及其他非生物胁迫因素诱导的过敏反应(HR)损伤。
经FA处理的番茄叶片因细胞死亡出现可见的坏死斑,伊文思蓝染色、活性氧(ROS)水平升高和DNA降解均证实了这一点。检测了经FA处理的番茄叶片中O和HO的生成变化以及超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX)的活性。观察到FA处理刺激叶片中的氧化爆发,导致O和HO生成持续激活。在施用FA的第一天后,HO清除酶CAT和APX活性大幅下降,随后在2天和3天后逐渐恢复到对照水平。
ROS生成增加、抗氧化酶活性下调以及脂质过氧化上调共同作用对细胞死亡的发生至关重要。这些结果表明FA诱导的损伤可能源于ROS途径。因此,我们的实验为研究FA诱导的植物细胞死亡提供了一个有用的模式植物系统。